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2023, Vol. 84, No. 9　Online: 15 September 2023

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Revelation of bimolecular tautomerization induced by the concerted and radical interactions in lignin pyrolysis Wen-luan Xie, Bin Hu, Wen-ming Zhang, He-long Li, Guo-yong Song, Ji Liu, Qiang Lu 2023, 84(9): 1-10.  DOI: 10.1016/j.jechem.2023.05.007 Abstract ( 20 )   PDF (7213KB) ( 26 )   Bimolecular interactions play crucial roles in lignin pyrolysis. The tautomerization of key intermediates has a significant impact on the formation of stable products, whereas bimolecular tautomerization has been rarely clarified. In the present work, the bimolecular tautomerization mechanism induced by both concerted and radical interactions was proposed and carefully confirmed. A characteristic b-O-4 lignin dimer, 2-phenoxy-1-phenylethanol (a-OH-PPE), was used as the model compound to reveal two representative keto-phenol and enol-keto tautomerism mechanisms, based on theoretical calculations combined with pyrolysis experiments. The results indicate that the unimolecular tautomerism as the rate-determining step limits product generation, due to fairly high energy barriers. While the free hydroxy compounds and radicals derived from initial pyrolysis can further initiate bimolecular tautomerism reactions through the one-step concerted hydroxyl-assisted hydrogen transfer (hydroxyl-AHT) and two-step radical hydrogen abstraction interactions, respectively. By alleviating and even avoiding the large ring tension of tautomerism, the unstable tautomers (2,4-cyclohexadienone and 1-hydroxystyrene) can be rapidly tautomerized into stable phenol and acetophenone with the help of intermolecular interaction. Benefitting from the significant advantage of retro-ene fragmentation in breaking the b-O-4 bond to form tautomers, a large amount of stable phenolic and ketone products can be generated following bimolecular tautomerization in the pyrolysis of b-O-4 linked lignin.

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Restraining migration and dissolution of transition-metal-ions via functionalized separator for Li-rich Mn-based cathode with high-energy-density Zhi Li, Bao Zhang, Gangyong Li, Shuang Cao, Changmeng Guo, Heng Li, Ruijuan Wang, Jiarui Chen, Lei Wu, Jiajia Huang, Yansong Bai, Xianyou Wang 2023, 84(9): 11-21.  DOI: 10.1016/j.jechem.2023.05.004 Abstract ( 18 )   PDF (17300KB) ( 31 )   Lithium-rich manganese-based materials (LRMs) are promising cathode for high-energy-density lithiumion batteries due to their high capacity, low toxicity, and low cost. However, LRMs suffer from serious voltage decay and capacity fade due to continual migration and dissolution of transition metal ions (TMs) during cycling process. Herein, a novel strategy is proposed to inhibit the TMs migration of LRMs through a modified separator by means of functionalized carbon coating layer, which depends on the chemical constraint of the abundant functional groups in the modified super P. In addition, it has been found that the dissolution of TMs can be restrained based on the Le Chatelier’s principle. Moreover, the modified separator owns good wettability toward the electrolyte. As a result, the LRMs cathode with the modified separator delivers a high discharge capacity of 329.93 mA h g1 at 0.1 C, and achieves good cyclic performance, the enhanced reaction kinetics and low voltage decay. Therefore, this work provides a new idea to promote the comprehensive electrochemical performances of Li-ion batteries with LRMs cathode through a strategy of separator modification.

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Enhancing Li cycling coulombic efficiency while mitigating ‘‘shuttle effect” of Li-S battery through sustained release of LiNO3 Qi Jin, Kaixin Zhao, Lili Wu, Lu Li, Long Kong, Xitian Zhang 2023, 84(9): 22-29.  DOI: 10.1016/j.jechem.2023.05.020 Abstract ( 10 )   PDF (7746KB) ( 22 )   In practical lithium-sulfur batteries (LSBs), the shuttle effect and Li cycling coulombic efficiency (CE) are strongly affected by the physicochemical properties of solid electrolyte interphase (SEI). LiNO3 is widely used as an additive in electrolytes to build a high-quality SEI, but its self-sacrificial nature limits the ability to mitigate the shuttle effect and stabilize Li anode during long-term cycling. To counteract LiNO3 consumption during long-term cycling without using a high initial concentration, inspired by sustainedrelease drugs, we encapsulated LiNO3 in lithiated Nafion polymer and added an electrolyte co-solvent (1,1,2,2-tetrafluoroethylene 2,2,2-trifluoromethyl ether) with poor LiNO3 solubility to construct highquality and durable F- and N-rich SEI. Theoretical calculations, experiments, multiphysics simulations, and in-situ observations confirmed that the F- and N-rich SEI can modulate lithium deposition behavior and allow persistent repair of SEI during prolonged cycling. Hence, the F- and N-rich SEI improves the Li anode cycling CE to 99.63% and alleviates the shuttle effect during long-term cycling. The lithium anode with sustainable F- and N-rich SEI shows a stable Li plating/stripping over 2000 h at 1 mA cm-2. As expected, Li||S full cells with this SEI achieved a long lifespan of 250 cycles, far exceeding cells with a routine SEI. The Li||S pouch cell based on F- and N-rich SEI also can achieve a high energy density of about 300 Wh kg-1 at initial cycles. This strategy provides a novel design for high-quality and durable SEIs in LSBs and may also be extendable to other alkali metal batteries.

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Battery prognostics and health management for electric vehicles under industry 4.0 Jingyuan Zhao, Andrew F. Burke 2023, 84(9): 30-33.  DOI: 10.1016/j.jechem.2023.04.042 Abstract ( 27 )   PDF (1396KB) ( 23 )

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Regulating the synergy coefficient of composite materials for alleviating self-discharge of supercapacitors Siqi Jing, Xiaohui Yan, Yige Xiong, Taibai Li, Junkai Xiong, Tao Hu, Zhongjie Wang, Liang Lou, Xiang Ge 2023, 84(9): 34-40.  DOI: 10.1016/j.jechem.2023.05.019 Abstract ( 5 )   PDF (5129KB) ( 8 )   Supercapacitor is an efficient energy storage device, yet its wider application is still limited by selfdischarge. Currently, various composite materials have been reported to have improved inhibition on self-discharge, while the evaluation of the synergistic effect in composite materials is challenging. Herein, pairs of intercalation type pseudocapacitive niobium oxides are pre-lithiated and coupled to construct conjugatedly configured supercapacitors, within which the cathode and anode experience identical reaction environment with single type of charge carrier, thus providing ideal platform to quantify the synergistic effect of composite materials on the self-discharge process. By using titanium dioxide as the stabilizer, we have compared how the modes of forming composite would influence the selfdischarge performance of the active composite materials with similar ratio of the constituent materials. Specifically, core@shell Nb2O5@TiO2 composite using TiO2 as the shell shows significantly higher synergy coefficient (l = 0.61, defined as the value that evaluates the synergistic effect between composite materials, and can be quantified using the overall performance of the composite, performance of individual component as well as the ratio of the component.) than other control group samples, which corresponds to the highest retained energy of 63% at 100 h. This work is expected to provide a general method for quantifying the synergistic effect and guide the design of composite materials with specific mode of forming the composite.

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Integrating thermal energy storage and microwave absorption in phase change material-encapsulated core-sheath MoS2@CNTs Panpan Liu, Yang Li, Zhaodi Tang, Junjun Lv, Piao Cheng, Xuemei Diao, Yu Jiang, Xiao Chen, Ge Wang 2023, 84(9): 41-49.  DOI: 10.1016/j.jechem.2023.04.048 Abstract ( 9 )   PDF (10676KB) ( 5 )   Developing advanced nanocomposite integrating solar-driven thermal energy storage and thermal management functional microwave absorption can facilitate the cutting-edge application of phase change materials (PCMs). To conquer this goal, herein, two-dimensional MoS2 nanosheets are grown in situ on the surface of one-dimensional CNTs to prepare core-sheath MoS2@CNTs for the encapsulation of paraffin wax (PW). Benefiting from the synergistic enhancement photothermal effect of MoS2 and CNTs, MoS2@CNTs is capable of efficiently trapping photons and quickly transporting phonons, thus yielding a high solar-thermal energy conversion and storage efficiency of 94.97%. Meanwhile, PW/MoS2@CNTs composite PCMs exhibit a high phase change enthalpy of 101.60 J/g and excellent long-term thermal storage durability after undergoing multiple heating-cooling cycles. More attractively, PW/MoS2@CNTs composite PCMs realize thermal management functional microwave absorption in heat-related electronic application scenarios, which is superior to the single microwave absorption of traditional materials. The minimum reflection loss (RL) for PW/MoS2@CNTs is -28 dB at 12.91 GHz with a 2.0 mm thickness. This functional integration design provides some insightful references on developing advanced microwave absorbing composite PCMs, holding great potential towards high-efficiency solar energy utilization and thermally managed microwave absorption fields.

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Manifolding active sites and in situ/operando electrochemical-Raman spectroscopic studies of single-metal nanoparticle-decorated CuO nanorods in furfural biomass valorization to H2 and 2-furoic acid Jiwon Kim, Talshyn Begildayeva, Jayaraman Theerthagiri, Cheol Joo Moon, Ahreum Min, Seung Jun Lee, Gyeong-Ah Kim, Myong Yong Choi 2023, 84(9): 50-61.  DOI: 10.1016/j.jechem.2023.05.042 Abstract ( 20 )   PDF (16183KB) ( 0 )   Here, CuO nanorods fabricated via pulsed laser ablation in liquids were decorated with Ir, Pd, and Ru NPs (loading ~ 7 wt%) through pulsed laser irradiation in the liquids process. The resulting NPs-decorated CuO nanorods were characterized spectroscopically and employed as multifunctional electrocatalysts in OER, HER, and the furfural oxidation reactions (FOR). Ir-CuO nanorods afford the lowest overpotential of ~ 345 mV (HER) and 414 mV (OER) at 10 mA cm-2, provide the highest 2-furoic acid yield (~10.85 mM) with 64.9% selectivity, and the best Faradaic efficiency ~72.7% in 2 h of FOR at 1.58 V (vs. RHE). In situ electrochemical-Raman analysis of the Ir-CuO detects the formation of the crucial intermediates, such as Cu(III)-oxide, Cu(OH)2, and Irx(OH)y, on the electrode-electrolyte surface, which act as a promoter for HER and OER. The Ir-CuO || Ir-CuO in a coupled HER and FOR-electrolyzer operates at~200 mV lower voltage, compared with the conventional electrolyzer and embodies the dual advantage of energy-saving H2 and 2-furoic acid production.

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Kinetic and thermodynamic synergy of organic small molecular additives enables constructed stable zinc anode Yang Gao, Mingshan Wang, Hao Wang, Xinpeng Li, Yuanwei Chu, Zhicheng Tang, Yuanlong Feng, Jiaqi Wang, Yong Pan, Zhiyuan Ma, Zhenliang Yang, Dan Zhou, Xing Li 2023, 84(9): 62-72.  DOI: 10.1016/j.jechem.2023.05.021 Abstract ( 33 )   PDF (12591KB) ( 17 )   An organic small molecule additive zinc formate is introduced to construct stable Zn metal interphase by electrochemical kinetic control and thermodynamic adjustment. It partially forms a water-formate concomitant dipole layer at the internal Helmholtz electrical double layers (HEDLs) under the preferential adsorption function of formate on Zn surface, reducing the occurrence of side reactions at phase interface. Meanwhile, free formate in HEDLs regulates the Zn2+ solvation sheath structure to accelerate the desolvation, transference, and deposition kinetics of Zn2+. Besides, the hydrolysis reaction of zinc formate increases the hydrogen evolution overpotential, inhibiting the thermodynamic tendency of hydrogen evolution. Consequently, it presents stable cycle for more than 2400 h at 5 mA cm-2, as well as an average Coulombic efficiency of 99.8% at 1 A g-1 after 800 cycles in the Zn||VO2 full cell. The interphase engineering strategy zinc anode by organic small molecular brings new possibility towards high-performance aqueous zinc-ion batteries.

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Alkaline hydrogen production promoted by small-molecule modification on flowerlike Co2(OH)2CO3 Yue Liu, Huan Zhang, Chen Yang, Ziyang Xu, Yiyang Shi, Xukun Zhu, Xinde Duan, Ling Qin, Yachao Jin, Li Song, Mingdao Zhang, Hegen Zheng 2023, 84(9): 73-80.  DOI: 10.1016/j.jechem.2023.05.013 Abstract ( 10 )   PDF (9850KB) ( 7 )   Developing a low-cost and high-efficiency nonprecious metal-based catalyst for hydrogen evolution reaction (HER) is of great significance for the utilization of hydrogen energy. In this work, we report a molecular-modification strategy to fabricate a self-supported hydrogen evolution electrode, specially by grafting the macrocyclic molecules (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) on the surface of a cobaltous dihydroxycarbonate (COC) seed layer. The HHTP-COC electrode is endowed with a rodlike structure, which provides favorable access for charge transportation and mass exchange. The macrocyclic molecule structure in HHTP can be grafted on COC and improve the electrical conductivity, while the interaction between HHTP and COC induces the rearrangement of charge configuration on the surface. Due to the combination effects of several aspects, the HHTP-COC electrode achieves astonishing HER activity, with a low overpotential of 61.0 mV (g10, at the current density of 10 mA cm-2) and excellent stability in alkaline condition. This kind of interface engineering based on the organic molecules can be applied to the design and manufacture of electrocatalysts in the field of energy conversion and storage.

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Rational screening of metal coating on Zn anode for ultrahighcumulative-capacity aqueous zinc metal batteries Dan Lv, Huili Peng, Cheng Wang, Hongxia Liu, Dongdong Wang, Jian Yang, Yitai Qian 2023, 84(9): 81-88.  DOI: 10.1016/j.jechem.2023.05.028 Abstract ( 2 )   PDF (11448KB) ( 1 )   Aqueous zinc metal batteries feature intrinsic safety, but suffer from severe dendrite growth and waterderived side reactions. Many metal coatings have been explored for stabilizing Zn metal anode via a trialand-error approach. Here, we propose an exercisable way to screen the potential metal coating on Zn anodes in view of de-polarization effect and dendrite-suppressing ability theoretically. As an output of this screening, cadmium (Cd) metal is checked experimentally. Therefore, symmetric Zn||Zn cells using Cd coated Zn (Zn@Cd) exhibit an ultra-long cycle life of 3500 h (nearly 5 months) at a high current density of 10 mA cm-2, achieving a record-high cumulative capacity (35 A h cm-2) compared to the previous reports. The full cells of Zn@Cd||MnO2 display a markedly improved cycling performance under harsh conditions including a limited Zn supply (N/P ratio = 1.7) and a high areal capacity (3.5 mA h cm-2). The significance of this work lies in not only the first report of Cd coating for stabilizing Zn metal anode, but also a feasible way to screen the promising metal materials for other metal anodes.

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Selective photocatalytic aerobic oxidative cleavage of lignin C-O bonds over sodium lignosulfonate modified Fe3O4/TiO2 Kejia Wu, Jinrong Liang, Sijie Liu, Yimin Huang, Minglong Cao, Qiang Zeng, Xuehui Li 2023, 84(9): 89-100.  DOI: 10.1016/j.jechem.2023.04.033 Abstract ( 1 )   PDF (7451KB) ( 4 )   Lignocellulose shows significantly potential in sustainable conversion to high-quality fuel and valueadded chemicals with the demands for realizing the rapid cycle of carbon resources and helping to reach carbon neutrality in nature. Selective tailoring of a-O-4, b-O-4, etc. linkages in lignin has always been viewed as ‘‘death blow” for its depolymerization. Herein, novel sodium lignosulfonate (SL) modified Fe3O4/TiO2 (SL-Fe3O4/TiO2) spherical particles have been developed and used as catalysts for selectively photocatalytic oxidative cleavage of organosolv lignin. As expected, 80% selective conversion of lignin in C2-C4 esters has been achieved, while C-O bonds in lignin model compounds can be effectively cleaved. Other than normal hydroxyl radical-mediated photocatalytic depolymerization of lignin over TiO2-based materials, in this contribution, mechanism studies indicate that photogenerated holes and superoxide anion radicals are main active species, which trigger the cleavage of a/b-O-4 bond, and the isotopelabeling study confirms the crucial factor of Cb-H dehydrogenation in cleavage of b-O-4 bonds.

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Facet effect on the reconstructed Cu-catalyzed electrochemical hydrogenation of 5-hydroxymethylfurfural (HMF) towards 2,5-bis (hydroxymethy)furan (BHMF) Mengxia Li, Tianxi Zheng, Dongfei Lu, Shiwei Dai, Xin Chen, Xinchen Pan, Dibo Dong, Rengui Weng, Gang Xu, Fanan Wang 2023, 84(9): 101-111.  DOI: 10.1016/j.jechem.2023.05.003 Abstract ( 2 )   PDF (7597KB) ( 2 )   The electrochemical hydrogenation of HMF to BHMF is an elegant alternative to the conventional thermocatalytic route for the production of high-value-added chemicals from biomass resources. In virtue of the wide potential window with promising Faradic efficiency (FE) towards BHMF, Cu-based electrode has been in the center of investigation. However, its structure-activity relationship remains ambiguous and its intrinsic catalytic activity is still unsatisfactory. In this work, we develop a two-step oxidation-reduction strategy to reconstruct the surface atom arrangement of the Cu foam (CF). By combination of multiple quasi-situ/in-situ techniques and density functional theory (DFT) calculation, the critical factor that governs the reaction is demonstrated to be facet effect of the metallic Cu crystal: Cu(110) facet accounts for the most favorable surface with enhanced chemisorption with reactants and selective production of BHMF, while Cu(100) facet might trigger the accumulation of the by-product 5,50-bis(hydroxy methy)hydrofurion (BHH). With the optimized composition of the facets on the reconstructed Cu(OH)2-ER/CF, the performance could be noticeably enhanced with a BHMF FE of 92.3% and HMF conversion of 98.5% at a potential of -0.15 V versus reversible hydrogen electrode (vs. RHE) in 0.1 M KOH solution. This work sheds light on the incomplete mechanistic puzzle for Cu-catalyzed electrochemical hydrogenation of HMF to BHMF, and provides a theoretical foundation for further precise design of highly efficient catalytic electrodes.

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Enhanced reconstruction of Fe5Ni4S8 by implanting pyrrolidone to unlock efficient oxygen evolution Zhengyan Du, Zeshuo Meng, Chao Jiang, Chenxu Zhang, Yanan Cui, Yaxin Li, Chong Wang, Xiaoying Hu, Shansheng Yu, Hongwei Tian 2023, 84(9): 112-121.  DOI: 10.1016/j.jechem.2023.05.026 Abstract ( 5 )   PDF (8706KB) ( 2 )   During oxygen evolution reaction (OER), complex changes have been reported on surfaces of bimetallic Fe-Ni-based catalysts, and regulating the dynamic evolution could improve their electrocatalytic performances. Herein, a pyrrolidone-promoted reconstruction of pentlandite was investigated to uncover the correlation between the reconstructed surface and the OER performance. The theoretical calculations indicated the preferential implantation of pyrrolidone at Fe atoms, useful for regulating the electronic structures of pentlandite. The valence state of Ni increased, suggesting the promotion of the in-situ reconstruction of pentlandite via strengthening hydroxyl adsorption to generate highly active NiOOH. The electron-rich pentlandite was also found conducive to charge transfer under applied voltages. The Operando Raman and various quasi-in-situ characterizations confirmed the realization of more delocalized electronic structures of pentlandite by introducing pyrrolidone. This, in turn, promoted the accumulation of hydroxyl groups on the pentlandite surface, thereby boosting the formation of highly active NiOOH at lower OER potentials. Consequently, the adsorption energies of intermediates were optimized, conducive to enhanced OER reaction kinetics. As a proof of concept, the pentlandite decorated by pyrrolidone exhibited an overpotential as low as 265 mV at 10 mA cm-2 coupled with stable catalysis for 1000 hours at a high current density of 100 mA cm-2. In sum, new insights into unlocking the high catalytic activity of bimetallic Fe-Ni-based catalysts were provided, promising for future synthesis of advanced catalysts.

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Rational design of Ni-MoO3-x catalyst towards efficient hydrodeoxygenation of lignin-derived bio-oil into naphthenes Chao Wang, Luxian Guo, Kui Wu, Xinxin Li, Yanping Huang, Zhigang Shen, Hongyun Yang, Yunquan Yang, Weiyan Wang, Changzhi Li 2023, 84(9): 122-130.  DOI: 10.1016/j.jechem.2023.05.029 Abstract ( 5 )   PDF (7386KB) ( 4 )   Design of a robust catalyst with high activity but the low cost for the hydrodeoxygenation (HDO) of biooils is of great importance to bring the biorefinery concept into reality. In this study, density functional theory (DFT) calculation was adopted to analyze the optimal location of Ni on MoO3-x containing oxygen vacancy, and the corresponding result demonstrated that metallic Ni cluster located at the neighborhood of oxygen vacancies would significantly evoke HDO activity. Enlightened by DFT results, NiMoO4 was first hydrothermally synthesized and then employed to fabricate Ni-MoO3-x catalyst via a low-temperature reduction, where Ni escaped from NiMoO4 and was reduced to its metallic state. Such an evolution of Ni species also induced the formation of oxygen vacancies around metallic Ni cluster. In the HDO of p-cresol, Ni-MoO3-x exhibited high activity with a complete conversion and a methylcyclohexane selectivity of 99.4% at 150 。C. Moreover, the catalyst showed good versatility in catalyzing HDO of diverse lignin-derived oxygenates and lignin oil. 2D HSQC NMR, gas chromatograph and elemental analysis of the lignin oil demonstrated the high deoxygenation efficiency and saturation of the benzene ring over Ni-MoO3-x. In the upgrading of crude lignin oil, the deoxygenation degree was up to 99%, and the overall carbon yield of the naphthenes was as high as 69.4%. Importantly, the structures and carbon numbers of the naphthene products are similar to jet fuel-range cycloalkanes, which are expected to have a high density that can be blended into jet fuel to raise the range (or payload) of airplanes. This work demonstrates the feasibility for improving the targeted catalytic reactivity by rational tailoring the catalyst structure under the guidance of theoretical analysis, and provides an energy-efficient route for the upgrading of lignin crude oil into valuable naphthenes.

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Design of novel transition-metal-doped C4N4 as highly effective electrocatalysts for nitrogen fixation with a new intrinsic descriptor Cheng He, Jianglong Ma, Yibo Wu, Wenxue Zhang 2023, 84(9): 131-139.  DOI: 10.1016/j.jechem.2023.05.022 Abstract ( 5 )   PDF (7449KB) ( 4 )   Electrocatalytic nitrogen reduction reaction (NRR) is an efficient and green way to produce ammonia, which offers an alternative option to the conventional Haber-Bosch process. Unfortunately, the large-scale industrial application of NRR processes is still hindered by poor Faraday efficiency and high overpotential, which need to be overcome urgently. Herein, combined with density functional theory and particle swarm optimization algorithm for the nitrogen carbide monolayer structural search (CmN8-m, m = 1-7), the surprising discovery is that single transition metal-atom-doped C4N4 monolayers (TM@C4N4) could effectively accelerate nitrogen reduction reaction. TM@C4N4 (TM = 29 transition metals) as single-atom catalysts are evaluated via traditional multi-step screening method, and their structures, NRR activity, selectivity and solvation effect are investigated to evaluate their NRR performance. Through the screening steps, W@C4N4 possesses the highest activity for NRR with a very low limiting potential of -0.29 V. Moreover, an intrinsic descriptor u is proposed with machine learning, which shortens the screening process and provides a new idea for finding efficient SACs. This work not only offers promising catalysts W@C4N4 for NRR process but also offers a new intrinsic and universal descriptor u.

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Boosting electrocatalytic activity with the formation of abundant heterointerfaces and N, S dual-doped carbon nanotube for rechargeable Zn-air battery Rin Na, Kyeongseok Min, Hyejin Kim, Yujin Son, Sang Eun Shim, Sung-Hyeon Baeck 2023, 84(9): 140-152.  DOI: 10.1016/j.jechem.2023.05.040 Abstract ( 8 )   PDF (9171KB) ( 2 )   Herein, a facile synthetic strategy is proposed to fabricate high-performance electrocatalysts for rechargeable Zn-air batteries (ZABs). Heterostructured NiCo/NiCo2S4 nanoparticles encapsulated in N-, S- co-doped CNT (NiCo/NiCo2S4@NSCNT) are synthesized via co-precipitation, thermal carbonization, and partial sulfidation processes. The strongly coupled NiCo/NiCo2S4 heterostructure can improve the redox property and charge transfer ability. Also, the CNTs with abundant foreign dopants provide high electrical conductivity and abundant defect sites for both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The prepared NiCo/NiCo2S4@NSCNT electrocatalyst exhibits a low overpotential of 349 mV at a current density of 10 mA cm-2 and a half-wave potential of 0.865 V for the OER and ORR, respectively. Moreover, the ZAB assembled using as-prepared NiCo/NiCo2S4@NSCNT can provide superior specific capacity (756.16 mA h gZn-1), peak power density (155.82 mW cm-2), and long-term cyclability compared to those of the precious metal-based electrocatalyst (Pt/C + RuO2).

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Occurrence of anionic redox with absence of full oxidation to Ru5+ in high-energy P2-type layered oxide cathode Jinho Ahn, Hyunyoung Park, Wonseok Ko, Yongseok Lee, Jungmin Kang, Seokjin Lee, Sangyeop Lee, Eunji Sim, Kyuwook Ihm, Jihyun Hong, Jung-Keun Yoo, Kyojin Ku, Jongsoon Kim 2023, 84(9): 153-161.  DOI: 10.1016/j.jechem.2023.05.016 Abstract ( 2 )   PDF (8899KB) ( 6 )   The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries (NIBs). It is known that an oxidation state of Mn4+ or Ru5+ is essential for the anionic reaction of O2-/O- to occur during Na+ de/intercalation. However, here, we report that the anionic redox can occur in Ru-based layered-oxide-cathodes before full oxidation of Ru4+/Ru5+. Combining studies using first-principles calculation and experimental techniques reveals that further Na+ deintercalation from P2-Na0.33[Mg0.33Ru0.67]O2 is based on anionic oxidation after 0.33 mol Na+ deintercalation from P2-Na0.67[Mg0.33Ru0.67]O2 with cationic oxidation of Ru4+/Ru4.5+. Especially, it is revealed that the only oxygen neighboring 2Mg/1Ru can participate in the anionic redox during Na+ de/intercalation, which implies that the Na-O-Mg arrangement in the P2-Na0.33[Mg0.33Ru0.67]O2 structure can dramatically lower the thermodynamic stability of the anionic redox than that of cationic redox. Through the O anionic and Ru cationic reaction, P2-Na0.67[Mg0.33Ru0.67]O2 exhibits not only a large specific capacity of ~172 mA h g-1 but also excellent power-capability via facile Na+ diffusion and reversible structural change during charge/discharge. These findings suggest a novel strategy that can increase the activity of anionic redox by modulating the local environment around oxygen to develop high-energy-density cathode materials for NIBs.

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Thermal runaway propagation behavior of the Cell-to-Pack battery system Huaibin Wang, Qinzheng Wang, Zhenyang Zhao, Changyong Jin, Chengshan Xu, Wensheng Huang, Zhuchen Yuan, Shuyu Wang, Yang Li, Yanhong Zhao, Junli Sun, Xuning Feng 2023, 84(9): 162-172.  DOI: 10.1016/j.jechem.2023.05.015 Abstract ( 14 )   PDF (11523KB) ( 19 )   Structurally compact battery packs significantly improve the driving range of electric vehicles. Technologies like Cell-to-Pack increase energy density by 15%-20%. However, the safety implications of multiple tightly-packed battery cells still require in-depth research. This paper studies thermal runaway propagation behavior in a Cell-to-Pack system and assesses propagation speed relative to other systems. The investigation includes temperature response, extent of battery damage, pack structure deformation, chemical analysis of debris, and other considerations. Results suggest three typical patterns for the thermal runaway propagation process: ordered, disordered, and synchronous. The synchronous propagation pattern displayed the most severe damage, indicating energy release is the largest under the synchronous pattern. This study identifies battery deformation patterns, chemical characteristics of debris, and other observed factors that can both be applied to identify the cause of thermal runaway during accident investigations and help promote safer designs of large battery packs used in large-scale electric energy storage systems.

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Surface reconstruction of Se-doped NiS2 enables high-efficiency oxygen evolution reaction Mengxin Chen, Yuanyuan Zhang, Ran Wang, Bin Zhang, Bo Song, Yanchao Guan, Siwei Li, Ping Xu 2023, 84(9): 173-180.  DOI: 10.1016/j.jechem.2023.05.009 Abstract ( 21 )   PDF (6461KB) ( 14 )   Surface reconstruction of electrocatalysts has been widely witnessed during the electrochemical processes. Here, NiS2, NiSe2, and Se doped NiS2 (Se-NiS2) are fabricated for oxygen evolution reaction (OER) through a mild sulfuration and/or selenylation process of Ni(OH)2 supported on carbon cloth (CC). Through careful in-situ Raman spectroscopy and ex-situ X-ray photoelectron spectroscopy, surface reconstruction of NiS2, NiSe2, and Se-NiS2 during the OER process has been revealed. A potential-dependent study shows that Se-NiS2 undergoes surface evolution at lower potentials and requires the lowest potential for conversion to NiOOH as a highly OER-active species, accompanied by the leaching of SO42- and SeO42- that can again be adsorbed on the catalyst surface to enhance the catalytic activity. Density functional theory (DFT) calculations confirm that Se-NiS2 is more susceptible to surface oxidation through the OER process. Therefore, Se-NiS2 exhibits outstanding OER activity and stability in alkaline conditions, requiring an overpotential of 343 mV at a current density of 50 mA cm-2. A novel insight is provided by our work in understanding the surface reconstruction and electrocatalytic mechanism of Ni-based chalcogenides.

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LiCoO2 sintering aid towards cathode-interface-enhanced garnet electrolytes Xiaoye Liu, Xiangkun Kong, Wenyi Xiang, Yining Jiang, Bingqinq Xiong, Weiwei Ping, Changrong Xia, Daoming Huan, Chengwei Wang 2023, 84(9): 181-188.  DOI: 10.1016/j.jechem.2023.04.046 Abstract ( 2 )   PDF (10184KB) ( 1 )   Garnet-type Li7La3Zr2O12 (LLZO) has high ionic conductivity and good compatibility with lithium metal. High-temperature processing has been proven an effective method to decrease the interface resistance of cathode|LLZO. However, its application is still hindered by the interlayer co-diffusion with the cathode and high sintering temperature (>1200 °C). In this work, a new garnet-type composite solid-state electrolyte (SSE) Li6.54La2.96Ba0.04Zr1.5Nb0.5O12-LiCoO2 (LLBZNO-LCO) is firstly proposed to improve the chemical stability and electrochemical properties of garnet with high-temperature processing. Small doses of LCO (3%) can significantly decrease the LCO|SSE interface resistance from 121.2 to 10.1 Ω cm2, while the sintering temperature of garnet-type LLBZNO decreases from 1230 to 1000 °C. The all-solid-state battery based on the sintered LLBZNO-LCO SSE exhibits excellent cycling stability. Our approach achieves an enhanced LCO|SSE interface and an improved sintering activity of garnet SSE, which provides a new strategy for optimizing the comprehensive performance of garnet SSE.

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A critical review on composite solid electrolytes for lithium batteries: Design strategies and interface engineering Tianqi Yang, Cheng Wang, Wenkui Zhang, Yang Xia, Hui Huang, Yongping Gan, Xinping He, Xinhui Xia, Xinyong Tao, Jun Zhang 2023, 84(9): 189-209.  DOI: 10.1016/j.jechem.2023.05.011 Abstract ( 6 )   PDF (23177KB) ( 4 )   The rapid development of new energy vehicles and 5G communication technologies has led to higher demands for the safety, energy density, and cycle performance of lithium-ion batteries as power sources. However, the currently used liquid carbonate compounds in commercial lithium-ion battery electrolytes pose potential safety hazards such as leakage, swelling, corrosion, and flammability. Solid electrolytes can be used to mitigate these risks and create a safer lithium battery. Furthermore, high-energy density can be achieved by using solid electrolytes along with high-voltage cathode and metal lithium anode. Two types of solid electrolytes are generally used: inorganic solid electrolytes and polymer solid electrolytes. Inorganic solid electrolytes have high ionic conductivity, electrochemical stability window, and mechanical strength, but suffer from large solid/solid contact resistance between the electrode and electrolyte. Polymer solid electrolytes have good flexibility, processability, and contact interface properties, but low room temperature ionic conductivity, necessitating operation at elevated temperatures. Composite solid electrolytes (CSEs) are a promising alternative because they offer light weight and flexibility, like polymers, as well as the strength and stability of inorganic electrolytes. This paper presents a comprehensive review of recent advances in CSEs to help researchers optimize CSE composition and interactions for practical applications. It covers the development history of solid-state electrolytes, CSE properties with respect to nanofillers, morphology, and polymer types, and also discusses the lithium-ion transport mechanism of the composite electrolyte, and the methods of engineering interfaces with the positive and negative electrodes. Overall, the paper aims to provide an outlook on the potential applications of CSEs in solid-state lithium batteries, and to inspire further research aimed at the development of more systematic optimization strategies for CSEs.

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Reactive ball-milling synthesis of Co-Fe bimetallic catalyst for efficient hydrogenation of carbon dioxide to value-added hydrocarbons Haipeng Chen, Chenwei Wang, Mengyang Zheng, Chenlei Liu, Wenqiang Li, Qingfeng Yang, Shixue Zhou, Xun Feng 2023, 84(9): 210-218.  DOI: 10.1016/j.jechem.2023.05.025 Abstract ( 18 )   PDF (13688KB) ( 6 )   Catalytic hydrogenation of CO2 using renewable hydrogen not only reduces greenhouse gas emissions, but also provides industrial chemicals. Herein, a Co-Fe bimetallic catalyst was developed by a facile reactive ball-milling method for highly active and selective hydrogenation of CO2 to value-added hydrocarbons. When reacted at 320 °C, 1.0 MPa and 9600 mL h-1 gcat-1, the selectivity to light olefin (C2=-C4=) and C5 + species achieves 57.3% and 22.3%, respectively, at a CO2 conversion of 31.4%, which is superior to previous Fe-based catalysts. The CO2 activation can be promoted by the CoFe phase formed by reactive ball milling of the Fe-Co3O4 mixture, and the in-situ Co2C and Fe5C2 formed during hydrogenation are beneficial for the C-C coupling reaction. The initial C-C coupling is related to the combination of CO species with the surface carbon of Fe/Co carbides, and the sustained C-C coupling is maintained by self-recovery of defective carbides. This new strategy contributes to the development of efficient catalysts for the hydrogenation of CO2 to value-added hydrocarbons.

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Tuning exsolution of nanoparticles in defect engineered layered perovskite oxides for efficient CO2 electrolysis Zhengrong Liu, Jun Zhou, Yueyue Sun, Xiangling Yue, Jiaming Yang, Lei Fu, Qinyuan Deng, Hongfei Zhao, Chaofan Yin, Kai Wu 2023, 84(9): 219-227.  DOI: 10.1016/j.jechem.2023.05.033 Abstract ( 3 )   PDF (14793KB) ( 1 )   Solid oxide electrolysis cell (SOEC) could be a potential technology to afford chemical storage of renewable electricity by converting water and carbon dioxide. In this work, we present the Ni-doped layered perovskite oxides, (La4Srn-4)0.9Ti0.9nNi0.1nO3n+2 with n = 5, 8, and 12 (LSTNn) for application as catalysts of CO2 electrolysis with the exsolution of Ni nanoparticles through a simple in-situ growth method. It is found that the density, size, and distribution of exsolved Ni nanoparticles are determined by the number of n in LSTNn due to the different stack structures of TiO6 octahedra along the c axis. The Ni doping in LSTNn significantly improved the electrochemical activity by increasing oxygen vacancies, and the Ni metallic nanoparticles afford much more active sites. The results show that LSTNn cathodes can successfully be manipulated the activity by controlling both the n number and Ni exsolution. Among these LSTNn (n = 5, 8, and 12), LSTN8 renders a higher activity for electrolysis of CO2 with a current density of 1.50A cm-2@2.0 V at 800 °C It is clear from these results that the number of n in (La4Srn-4)0.9Ti0.9nNi0.1nO3n+2 with Ni-doping is a key factor in controlling the electrochemical performance and catalytic activity in SOEC.

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Overview of multi-stage charging strategies for Li-ion batteries Muhammad Usman Tahir, Ariya Sangwongwanich, Daniel-Ioan Stroe, Frede Blaabjerg 2023, 84(9): 228-241.  DOI: 10.1016/j.jechem.2023.05.023 Abstract ( 7 )   PDF (5146KB) ( 7 )   To reduce the carbon footprint in the transportation sector and improve overall vehicle efficiency, a large number of electric vehicles are being manufactured. This is due to the fact that environmental concerns and the depletion of fossil fuels have become significant global problems. Lithium-ion batteries (LIBs) have been distinguished themselves from alternative energy storage technologies for electric vehicles (EVs) due to superior qualities like high energy and power density, extended cycle life, and low maintenance cost to a competitive price. However, there are still certain challenges to be solved, like EV fast charging, longer lifetime, and reduced weight. For fast charging, the multi-stage constant current (MSCC) charging technique is an emerging solution to improve charging efficiency, reduce temperature rise during charging, increase charging/discharging capacities, shorten charging time, and extend the cycle life. However, there are large variations in the implementation of the number of stages, stage transition criterion, and C-rate selection for each stage. This paper provides a review of these problems by compiling information from the literature. An overview of the impact of different design parameters (number of stages, stage transition, and C-rate) that the MSCC charging techniques have had on the LIB performance and cycle life is described in detail and analyzed. The impact of design parameters on lifetime, charging efficiency, charging and discharging capacity, charging speed, and rising temperature during charging is presented, and this review provides guidelines for designing advanced fast charging strategies and determining future research gaps.

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LDH-based nanomaterials for photocatalytic applications: A comprehensive review on the role of bi/trivalent cations, anions, morphology, defect engineering, memory effect, and heterojunction formation Azmat Ali Khan, Muhammad Tahir, Nazish Khan 2023, 84(9): 242-276.  DOI: 10.1016/j.jechem.2023.04.049 Abstract ( 12 )   PDF (25385KB) ( 11 )   Using sunlight to drive chemical reactions via photocatalysis is paramount for a sustainable future. Among several photocatalysts, employing layered double hydrides (LDH) for photocatalytic application is most straightforward and desirable owing to their distinctive two-dimensional (2D) lamellar structure and optical attributes. This article reviews the advancements in bimetallic/trimetallic LDHs and various strategies to achieve high efficiency toward an outstanding performing photocatalyst. Firstly, the tuning of LDH components that control the electronic and structural properties is explained. The tuning obtained through the adoption, combination, and incorporation of different cations and anions is also explained. The progress of modification methods, such as the adoption of different morphologies, delamination, and defect engineering towards enhanced photocatalytic activities, is discussed in the mainstream. The band engineering, structural characteristics, and redox tuning are further deliberated to maximize solar energy harvesting for different photocatalytic applications. Finally, the progress obtained in forming hierarchical heterostructures through hybridization with other semiconductors or conducting materials is systematically disclosed to get maximum photocatalytic performance. Moreover, the structural changes during the in-situ synthesis of LDH and the stability of LDH-based photocatalysts are deliberated. The review also summarizes the improvements in LDH properties obtained through modification tactics and discusses the prospects for future energy and environmental applications.

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Surface modification of Cu2O with stabilized Cu+ for highly efficient and stable CO2 electroreduction to C2+ chemicals Ziyu Zhou, Shuyu Liang, Jiewen Xiao, Tianyu Zhang, Min Li, Wenfu Xie, Qiang Wang 2023, 84(9): 277-285.  DOI: 10.1016/j.jechem.2023.04.040 Abstract ( 18 )   PDF (7266KB) ( 11 )   Copper (Cu)-based materials are known as the most attractive catalysts for electrochemical carbon dioxide reduction reaction (CO2RR), especially the Cu+ species (e.g., Cu2O), which show excellent capability for catalyzing CO2 to C2+ chemicals because of their unique electronic structure. However, the active Cu+ species are prone to be reduced to metallic Cu under an electroreduction environment, thus resulting in fast deactivation and poor selectivity. Here, we developed an advanced surface modification strategy to maintain the active Cu+ species via assembling a protective layer of metal-organic framework (copper benzenetricarboxylate, CuBTC) on the surface of Cu2O octahedron (Cu2O@CuBTC). It's encouraging to see that the Cu2O@CuBTC heterostructure outperforms the bare Cu2O octahedron in catalyzing CO2 to C2+ chemicals and dramatically enhances the ratio of C2H4/CH4 products. A systematic study reveals that the introduced CuBTC shell plays a critical role in maintaining the active Cu+ species in Cu2O@CuBTC heterostructure under reductive conditions. This work offers a practical strategy for improving the catalytic performance of CO2RR over copper oxides and also establishes a route to maintain the state of valence-sensitive catalysts.

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Tracking gassing behavior in pouch cell by operando on-line electrochemical mass spectrometry Haitang Zhang, Jianken Chen, Baodan Zhang, Xiaohong Wu, Zhengang Li, Leiyu Chen, Junhao Wang, Xiaoyu Yu, Haiyan Luo, Jiyuan Xue, Yu-Hao Hong, Yu Qiao, Shi-Gang Sun 2023, 84(9): 286-291.  DOI: 10.1016/j.jechem.2023.04.044 Abstract ( 43 )   PDF (8378KB) ( 38 )

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The mitigation of pitch-derived carbon with different structures on the volume expansion of silicon in Si/C composite anode Xin Xue, Xiao Liu, Bin Lou, Yuanxi Yang, Nan Shi, FuShan Wen, Xiujie Yang, Dong Liu 2023, 84(9): 292-302.  DOI: 10.1016/j.jechem.2023.04.004 Abstract ( 8 )   PDF (17639KB) ( 6 )   The microstructures of carbon precursors significantly affect the electrochemical performance of Si/C composite anodes. However, the interaction between Si and carbon materials with different structures is still unclear. Pitch-based materials undergoing different thermal treatments are superior sources for synthesizing carbons with different structures. Herein, different types of mesophase pitch (domain, flow-domain and mosaic structure) obtained from controllable thermal condensation are utilized to prepare Si/C composite materials and the corresponding models are established through finite element simulation to explore the correlation between the lithium storage properties of Si/C composites and the structures of carbon materials. The results indicate that the flow-domain texture pitch P2 has a better ability to buffer the volume expansion of silicon particles for its highly ordered arrangement of carbon crystallites inside could disperse the swelling stress uniformly alongside the particle surface. The sample Si@P2 exhibits the highest capacity of 1328 mA h/g after 200 cycles at a current density of 0.1 A/g as well as the best rate performance and stability. While sample Si@P3 in which the mosaic texture pitch P3 composed of random orientation of crystallites undergoes the fastest capacity decay. These findings suggest that highly ordered carbon materials are more suitable for the synthesis of Si/C composite anodes and provide insights for understanding the interaction between carbon and silicon during the charging/discharging process.

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Sub-2 nm mixed metal oxide for electrochemical reduction of carbon dioxide to carbon monoxide Devina Thasia Wijaya, Andi Haryanto, Hyun Woo Lim, Kyoungsuk Jin, Chan Woo Lee 2023, 84(9): 303-310.  DOI: 10.1016/j.jechem.2023.03.060 Abstract ( 9 )   PDF (7426KB) ( 5 )   Mixed metal oxide (MMO) represents a critical class of materials that can allow for obtaining a dynamic interface between its components: reduced metal and its metal oxide counterpart during an electrocatalytic reaction. Here, a synthetic method utilizing a MOF-derived micro/mesoporous carbon as a template to prepare sub-2 nm MMO catalysts for CO2 electroreduction is reported. Starting from the zeolite imidazolate framework (ZIF-8), the pyrolyzed derivatives were used to synthesize sub-2 nm Pd-Ni MMO with different compositions. The Ni-rich (Pd20-Ni80/ZC) catalyst exhibits unexpectedly superior performance for CO production with an improved Faradaic efficiency (FE) of 95.3% at the current density of 200 mA cm-2 at -0.56 V vs. reversible hydrogen electrode (RHE) compared to other Pd-Ni compositions. X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of Ni2+ and Pd2+ in all compositions, demonstrating the presence of MMO. Density functional theory (DFT) calculation reveals that the lower CO binding energy on the surface of the Pd20-Ni80 cluster eases CO desorption, thus increasing its production. This work provides a general synthetic strategy for MMO electrocatalysts and can pave a new way for screening multimetallic catalysts with a dynamic electrochemical interface.

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Low-cost biodegradable lead sequestration film for perovskite solar cells Yiming Xiong, Haoyu Cai, Wang Yue, Wenjian Shen, Xuehao Zhu, Juan Zhao, Fuzhi Huang, Yi-Bing Cheng, Jie Zhong 2023, 84(9): 311-320.  DOI: 10.1016/j.jechem.2023.04.045 Abstract ( 4 )   PDF (20232KB) ( 3 )   Despite the high efficiency that has been achieved for the perovskite solar cells (PSCs), the hazardous lead leakage from the perovskite absorber layer is one of the crucial barriers still hindering its penetration into the commercial market for a large-scale installation. Herein, we report a novel low-cost and biodegradable lead sequestration layer with high compatibility for up-scalable encapsulation of PSCs. Through a precisely designed cross-linking reaction of chemical agents, the as-made biodegradable chitosan composite film shows enhanced mechanical strength, chemical stability, and lead adsorption capacity. The designed encapsulation strategy reduces over 99.99% lead leakage to <2 ppb under varied simulations of weather conditions (hail, rain, or flood), which meet the safe level of drinking water set by the US Environmental Protection Agency (EPA). Moreover, the PSC efficiency is improved from 21.91% to 22.82% due to the improved light absorption from the printed biodegradable lead absorption film. Finally, we present a prototype process of accumulation and recycling of lead compounds in PSCs derbies via the biodegradation process. Based on the low-cost biodegradable lead sequestration film, this environmental-friendly encapsulation strategy could address the lead leakage issue for further commercialization of PSCs.

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Nitrogen cold plasma treatment stabilizes Cu0/Cu+ electrocatalysts to enhance CO2 to C2 conversion Qiang Zhang, Jianlin Wang, Fang Guo, Ge He, Xiaohui Yang, Wei Li, Junqiang Xu, Zongyou Yin 2023, 84(9): 321-328.  DOI: 10.1016/j.jechem.2023.05.008 Abstract ( 2 )   PDF (5895KB) ( 2 )   Cu-based materials are ideal catalysts for CO2 electrocatalytic reduction reaction (CO2RR) into multi-carbon products. However, such reactions require stringent conditions on local environments of catalyst surfaces, which currently are the global pressing challenges. Here, a stabilized activation of Cu0/Cu+-on-Ag interface by N2 cold plasma treatment was developed for improving Faradaic efficiency (FE) of CO2RR into C2 products. The resultant Ag@Cu-CuNx exhibits a C2 FE of 72% with a partial current density of -14.9 mA cm-2 at -1.0 V vs. RHE (reversible hydrogen electrode). Combining density functional theory (DFT) and experimental investigations, we unveiled that Cu0/Cu+ species can be controllably tuned by the incorporation of nitrogen to form CuNx on Ag surface, i.e., Ag@Cu-CuNx. This strategy enhances *CO intermediates generation and accelerates C-C coupling both thermodynamically and kinetically. The intermediates O*C*CO, *COOH, and *CO were detected by in-situ attenuated total internal reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). The uncovered CO2RR-into-C2 products were carried out along CO2→ *COOH → *CO → O*C*CO → *C2H3O → *C2H4O → C2H5OH (or *C2H3O → *O + C2H4) paths over Ag@Cu-CuNx electrocatalyst. This work provides a new approach to design Cu-based electrocatalysts with high-efficiency, mild condition, and stable CO2RR to C2 products.

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Bridging the microstructural evolutions from slurry to porous electrode of a lithium-ion battery Hamid Hamed, Zoleikha Mirzaie Alamooti, Ashutosh Agrawal, Jan D’Haen, An Hardy, Mohammadhosein Safari 2023, 84(9): 329-334.  DOI: 10.1016/j.jechem.2023.05.024 Abstract ( 22 )   PDF (5504KB) ( 12 )

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Boosting battery state of health estimation based on self-supervised learning Yunhong Che, Yusheng Zheng, Xin Sui, Remus Teodorescu 2023, 84(9): 335-346.  DOI: 10.1016/j.jechem.2023.05.034 Abstract ( 16 )   PDF (10161KB) ( 8 )   State of health (SoH) estimation plays a key role in smart battery health prognostic and management. However, poor generalization, lack of labeled data, and unused measurements during aging are still major challenges to accurate SoH estimation. Toward this end, this paper proposes a self-supervised learning framework to boost the performance of battery SoH estimation. Different from traditional data-driven methods which rely on a considerable training dataset obtained from numerous battery cells, the proposed method achieves accurate and robust estimations using limited labeled data. A filter-based data preprocessing technique, which enables the extraction of partial capacity-voltage curves under dynamic charging profiles, is applied at first. Unsupervised learning is then used to learn the aging characteristics from the unlabeled data through an auto-encoder-decoder. The learned network parameters are transferred to the downstream SoH estimation task and are fine-tuned with very few sparsely labeled data, which boosts the performance of the estimation framework. The proposed method has been validated under different battery chemistries, formats, operating conditions, and ambient. The estimation accuracy can be guaranteed by using only three labeled data from the initial 20% life cycles, with overall errors less than 1.14% and error distribution of all testing scenarios maintaining less than 4%, and robustness increases with aging. Comparisons with other pure supervised machine learning methods demonstrate the superiority of the proposed method. This simple and data-efficient estimation framework is promising in real-world applications under a variety of scenarios.

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Alternative lead-free mixed-valence double perovskites for high-efficiency photovoltaic applications Wenbo Li, Yuheng Li, Zilong Zhang, Peng Gao 2023, 84(9): 347-353.  DOI: 10.1016/j.jechem.2023.05.037 Abstract ( 6 )   PDF (5028KB) ( 1 )   Lead-based organic-inorganic hybrid perovskites have exhibited great potential in photovoltaics, achieving power conversion efficiencies (PCEs) exceeding 25%. However, the toxicity of lead and the instability of these materials under moist conditions pose significant barriers to large-scale production. To overcome these limitations, researchers have proposed mixed-valence double perovskites, where Cs2AuIAuIIII6 is a particularly effective absorber due to its suitable band gap and high absorptance efficiency. To further extend the scope of these lead-free materials, we varied the trivalent gold ion and halogen anion in Cs2AuIAuIIII6, resulting in 18 new structures with unique properties. Further, using first-principles calculations and elimination criteria, we identified four materials with ideal band gaps, small effective carrier mass, and strong anisotropic optical properties. According to theoretical modeling, Cs2AuSbCl6, Cs2AuInCl6, and Cs2AuBiCl6 are potential candidates for solar cell absorbers, with a spectroscopic limited maximum efficiency (SLME) of approximately 30% in a 0.25 μm-thick film. These three compounds have not been previously reported, and therefore, our work provides new insights into potential materials for solar energy conversion. We aim for this theoretical exploration of novel perovskites to guide future experiments and accelerate the development of high-performance photovoltaic devices.

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Boosting efficiency and stability of 2D alternating cation perovskite solar cells via rational surface-modification: Marked passivation efficacy of anion Hualin Zheng, Xuefeng Peng, Tingxi Chen, Ting Zhang, Shihao Yuan, Lei Wang, Feng Qian, Jiang Huang, Xiaodong Liu, Zhi David Chen, Yanning Zhang, Shibin Li 2023, 84(9): 354-362.  DOI: 10.1016/j.jechem.2023.05.046 Abstract ( 10 )   PDF (4757KB) ( 2 )   Two-dimensional (2D) alternating cation (ACI) perovskite surface defects, especially dominant iodine vacancies (VI) and undercoordinated Pb2+, limit the performance of perovskite solar cells (PVSCs). To address the issue, 1-butyl-3-methylimidazolium trifluoro-methane-sulfonate (BMIMOTF) and its iodide counterpart (BMIMI) are utilized to modify the perovskite surface respectively. We find that BMIMI can change the perovskite surface, whereas BMIMOTF shows a nondestructive and more effective defect passivation, giving significantly reduced defect density and suppressed charge-carrier nonradiative recombination. This mainly attributes to the marked passivation efficacy of OTF- anion on VI and undercoordinated Pb2+, rather than BMIMI+ cation. Benefiting from the rational surface-modification of BMMIMOTF, the films exhibit an optimized energy level alignment, enhanced hydrophobicity and suppressed ion migration. Consequently, the BMIMOTF-modified devices achieve an impressive efficiency of 21.38% with a record open-circuit voltage of 1.195 V, which is among the best efficiencies reported for 2D PVSCs, and display greatly enhanced humidity and thermal stability.

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Hollow ZSM-5 encapsulated with single Ga-atoms for the catalytic fast pyrolysis of biomass waste Liu Wu, Junjie Xin, Yonggang Wang, Kexin Zhang, Jiaren Zhang, Junliang Sun, Ruqiang Zou, Jie Liang 2023, 84(9): 363-373.  DOI: 10.1016/j.jechem.2023.06.006 Abstract ( 17 )   PDF (9126KB) ( 10 )   The development of efficient metal-zeolite bifunctional catalysts for catalytic fast pyrolysis (CFP) of biomass waste is highly desirable for bioenergy and renewable biofuel production. However, conventional metal-loaded zeolites often suffer from metal sintering during pyrolysis and are thus inactivated. In this study, single-site Ga-functionalized hollow ZSM-5 (GaOx@HS-Z5) was synthesized via an impregnation-dissolution-recrystallization strategy without H2 reduction. The Ga atom was coordinated to four oxygen atoms in HS-Z5 frameworks. Benefitting from the highly dispersed single-Ga atoms and hollow zeolite framework, 3GaOx@HS-Z5 performed the best in producing hydrocarbon-rich bio-oil compared to impregnated 3GaOx/HS-Z5 and H2-reduced 3Ga@HS-Z5 in the maize straw CFP. In particular, 3GaOx@HS-Z5 delivered the highest bio-oil yield (23.6 wt%) and hydrocarbon selectivity (49.4 area%). 3GaOx@HS-Z5 also retained its structural integrity and catalytic activity after five pyrolysis-regeneration cycles, demonstrating its advantage in practical biomass CFP. The elimination of H2 reduction during the synthesis of catalyst provides an additional advantage for simplifying the CFP process and reducing operating costs. The retained Ga micro-environment and anti-sintering properties were unique for 3GaOx@HS-Z5, as severe metal sintering occurred during pyrolysis for other metals (e.g., NiOx, ZnOx, FeOx, and CoOx) that encapsulated HS-Z5.

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Flame-retardant oligomeric electrolyte additive for self-extinguishing and highly-stable lithium-ion batteries: Beyond small molecules Yi-Zhou Quan, Qing-Song Liu, Mei-Chen Liu, Guo-Rui Zhu, Gang Wu, Xiu-Li Wang, Yu-Zhong Wang 2023, 84(9): 374-384.  DOI: 10.1016/j.jechem.2023.05.041 Abstract ( 9 )   PDF (16580KB) ( 5 )   Preparing both safe and high-performance lithium-ion batteries (LIBs) based on commonly used commercial electrolytes is highly desirable, yet challenging. To overcome the poor compatibility of conventional small-molecular flame-retardants as electrolyte additives for safe LIBs with graphite anodes, in this study, we propose and design a novel low-cost flame-retardant oligomer that achieves an accurate and complete reconciliation of fire safety and electrochemical performance in LIBs. Owing to the integration of phosphonate units and polyethylene glycol (PEG) chains, this oligomer, which is a phosphonate-containing PEG-based oligomer (PPO), not only endows commercial electrolytes with excellent flame retardancy but also helps stabilize the electrodes and Li-ion migration. Specifically, adding 15 wt% of PPO can reduce 70% of the self-extinguishing time and 54% of total heat release for commercial electrolytes. Moreover, LiFePO4/lithium and graphite/lithium cells as well as LiFePO4/graphite pouch full cells exhibit good long-term cycling stability.

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Electrochemical urea synthesis by co-reduction of CO2 and nitrate with FeII-FeIIIOOH@BiVO4 heterostructures Hua-Qing Yin, Zuo-Shu Sun, Qiu-Ping Zhao, Lu-Lu Yang, Tong-Bu Lu, Zhi-Ming Zhang 2023, 84(9): 385-393.  DOI: 10.1016/j.jechem.2023.05.032 Abstract ( 7 )   PDF (6387KB) ( 13 )   Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns. Electrocatalytic C-N coupling by converting nitrate and CO2 into urea under ambient conditions represents a promising alternative process. But it was still limited by the strong competition between nitrate electrochemical reduction (NO3ER) and CO2 electrochemical reduction (CO2ER). Here, FeII-FeIIIOOH@BiVO4-n heterostructures are constructed through hydrothermal synthesis and exhibited superior performance toward urea electrosynthesis with NO3- and CO2 as feedstocks. The optimized urea yield and Faradaic efficiency over FeII-FeIIIOOH@BiVO4-2 can reach 13.8 mmol h-1 g-1 and 11.5% at -0.8 V vs. reversible hydrogen electrode, which is much higher than that of bare FeOOH (3.2 mmol h-1 g-1 and 1.3%), pristine BiVO4 (2.0 mmol h-1 g-1 and 5.4%), and the other FeII-FeIIIOOH@BiVO4-n (n = 1, 3, 5) heterostructures. Systematic experiments have verified that BiVO4 and FeOOH are subreaction active sites towards simultaneous CO2ER and NO3ER, respectively, achieving co-activation of CO2 and NO3- on FeII-FeIIIOOH@BiVO4-2. Moreover, the urea synthesis via the *CO and NO* intermediates and C-N coupling was confirmed by the in situ Fourier transform infrared spectroscopy. This work not only alleviates the CO2 emission and nitrate pollution but also presents an efficient catalyst for synergistic catalysis towards sustainable urea synthesis.

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Enhancing ammonia production rates from electrochemical nitrogen reduction by engineering three-phase boundary with phosphorus-activated Cu catalysts Jeehye Kim, Cho Hee Lee, Yong Hyun Moon, Min Hee Lee, Eun Hyup Kim, Sun Hee Choi, Youn Jeong Jang, Jae Sung Lee 2023, 84(9): 394-401.  DOI: 10.1016/j.jechem.2023.05.047 Abstract ( 18 )   PDF (4225KB) ( 19 )   Electrochemical N2 reduction reaction (eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N2 molecules and the limited supply of N2 to the catalyst due to its low solubility in aqueous electrolytes. Herein, we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N2 molecules. The eNRR system is further modified using a gas diffusion electrode (GDE) coated with polytetrafluoroethylene (PTFE) to form an effective three-phase boundary of liquid water - gas N2 - solid catalyst to facilitate easy access of N2 to the catalytic sites. As a result, the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH3 production rate of 7.69 μg h-1 cm-2 at -0.2 VRHE, which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic cell. This work represents a successful demonstration of dual modification strategies; catalyst modification and N2 supplying system engineering, and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.

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An upgraded polymeric composite with interparticle chemical bonding microstructure toward lithium-ion battery separators with enhanced safety and electrochemical performances Qian Zhao, Ling Ma, Ye Xu, Xiulong Wu, Shuai Jiang, Qiaotian Zheng, Guang Hong, Bin He, Chen Li, Wanglai Cen, Wenjun Zhou, Yan Meng, Dan Xiao 2023, 84(9): 402-413.  DOI: 10.1016/j.jechem.2023.05.050 Abstract ( 6 )   PDF (12623KB) ( 0 )   A composite separator of SiC/PVDF-HFP was synthesized for lithium-ion batteries with high thermal and mechanical stabilities. Benefiting from the nanoscale, high hardness, and melting point of SiC, SiC/PVDF-HFP with highly uniform microstructure was obtained. This polarization caused by barrier penetration was significantly restrained. Due to the Si-F bond between SiC and PVDF-HFP, the structural stability has been obviously enhanced, which could suppress the growth of lithium (Li) dendrite. Furthermore, some 3D reticulated Si nanowires are found on the surface of Li anode, which also greatly inhibit Li dendrites and result in irregular flakes of Li metal. Especially, the shrinkage of 6% SiC/PVDF-HFP at 150 °C is only 5%, which is notably lower than those of PVDF-HFP and Celgard2500. The commercial LiFePO4 cell assembled with 6% SiC/PVDF-HFP possesses a specific capacity of 157.8 mA h g-1 and coulomb efficiency of 98% at 80 °C. In addition, the tensile strength and modulus of 6% SiC/PVDF-HFP could reach 14.6 and 562 MPa, respectively. And a small deformation (1000 nm) and strong deformation recovery are obtained under a high additional load (2.3 mN). Compared with PVDF-HFP and Celgard2500, the symmetric Li cell assembled with 6% SiC/PVDF-HFP has not polarized after 900 cycles due to its excellent mechanical stabilities. This strategy provides a feasible solution for the composite separator of high-safety batteries with a high temperature and impact resistance.

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Rechargeable Na-MnO2 battery with modified cell chemistry Sirugaloor Thangavel Senthilkumar, Rebeca Marcilla, Youngsik Kim, Jesus Palma, Mani Ulaganathan, Jeong-Sun Park 2023, 84(9): 414-423.  DOI: 10.1016/j.jechem.2023.05.044 Abstract ( 13 )   PDF (10222KB) ( 5 )   High voltage, high energy density, nominal cycle life, and low cost are the most critical requirements of rechargeable batteries for their widespread energy storage applications in electric vehicles and renewable energy technologies. Na-MnO2 battery could be a low-cost contender, but it suffers extensively from its low cell voltage and poor rechargeability. In this study, we modified the conventional cell structure of Na-MnO2 battery and established altered cell chemistry through a hybrid electrochemical process consisting of Na striping/plating at the anode and Zn2+ insertion/de-insertion along with MnO2 dissolution/deposition at the cathode. After the modification, Na-MnO2 battery exhibits a discharge capacity of 267.10 mA h/g and a cell voltage of 3.30 V (vs. Na/Na+), resulting in a high specific energy density of 881.43 Wh/kg. After 300 cycles, the battery retains 98% of its first-cycle discharge capacity with 100% coulombic efficiency. Besides, Na metal-free battery assembled using sodium biphenyl as a safer anode also delivers an excellent energy density of 810.0 Wh/kg. This work could provide a feasible method to develop an advanced Na-MnO2 battery for real-time energy storage applications.

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Challenges and opportunities in plasma-activated reactions of CO2 with light alkanes Lea R. Winter, Jingguang G. Chen 2023, 84(9): 424-427.  DOI: 10.1016/j.jechem.2023.05.038 Abstract ( 9 )   PDF (1682KB) ( 8 )

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Close-loop recyclable and flexible halide perovskite@wool keratin sensor with piezoelectric property Yingying Zhou, Dangge Gao, Bin Lyu, Chi Zheng, Litao Tang, Shihao Guo, Jianzhong Ma 2023, 84(9): 428-435.  DOI: 10.1016/j.jechem.2023.05.005 Abstract ( 4 )   PDF (10779KB) ( 1 )   Halide perovskites with excellent piezoelectric properties, but their poor stability hinders their large-scale application. Herein, a sandwich-structured halide perovskite flexible sensor with good stability was developed according to a three-step procedure as follows: (i) in-situ growth of wool keratin-CsPbBr3 (WK-CsPbBr3) using wool keratin in interfacial passivation and coating, (ii) electrospinning of a wool keratin-CsPbBr3/polyacrylonitrile (WCP) nanofiber film, and (iii) coating of the WCP nanofiber with polydimethylsiloxane (PDMS) to obtain a sensor (WCPP). The sensor could generate a piezoelectric voltage of 7.8 V at a pressure of 6 kPa in the stages of pressing and releasing, and the output characteristics did not decline even after 10,000 cycles. Compared to the 4-month stability of the perovskite sensor, WCPP sensor exhibited the output performance even after 16 months, which indicated that wool keratin as a multidentate improved the stability of the halide perovskite. Additionally, the sensor displayed a self-cleaning property and could also light up 14 commercial LEDs. The close-loop recycling of the lead halide perovskite was achieved by dissolving the WCP nanofiber film in DMF and then re-electrospinning. Therefore, the method proposed is a step forward for achieving the commercialization of WK-CsPbBr3 and providing new avenues for further utilization of wool waste.

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Dependence of lithium metal battery performances on inherent separator porous structure regulation Lei Ding, Dandan Li, Lingyang Liu, Pengfang Zhang, Fanghui Du, Chao Wang, Daoxin Zhang, Shuo Zhang, Sihang Zhang, Feng Yang 2023, 84(9): 436-447.  DOI: 10.1016/j.jechem.2023.06.002 Abstract ( 5 )   PDF (23216KB) ( 4 )   Boosting of rechargeable lithium metal batteries (LMBs) holds challenges because of lithium dendrites germination and high-reactive surface feature. Separators may experience structure-determined chemical deterioration and worsen Li plating-stripping behaviors when smoothly shifting from lithium-ion batteries (LIBs) to LMBs. This study precisely regulations the crystal structure of β-polypropylene and separator porous construction to investigate the intrinsic porous structure and mechanical properties determined electrochemical performances and cycling durability of LMBs. Crystal structure characterizations, porous structure analyses, and electrochemical cycling tests uncover appropriate annealing thermal stimulation concentrates β-lamellae thickness and enhances lamellae thermal stability by rearranging molecular chain in inferior β-lamellae, maximally homogenizing biaxial tensile deformation and resultant porous constructions. These even pores with high connectivity lower ion migration barriers, alleviate heterogeneous Li+ flux dispersion, stabilize reversible Li plating-stripping behaviors, and hinder coursing and branching of Li dendrites, endowing steady cell cycling durability, especially at higher currents due to the highlighted uncontrollable cumulation of dead Li, which offers new insights for the current pursuit of high-power density battery and fast charging technology. The suggested separator structure-chemical nature functions in ensuring cyclic cell stability and builds reliable relationships between separator structure design and practical LMBs applications.

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Multicomponent mixed metallic hierarchical ZnNi@Ni@PEDOT arrayed structures as advanced electrode for high-performance hybrid electrochemical cells Anki Reddy Mule, Bhimanaboina Ramulu, Shaik Junied Arbaz, Jae Su Yu 2023, 84(9): 448-458.  DOI: 10.1016/j.jechem.2023.05.017 Abstract ( 6 )   PDF (12720KB) ( 3 )   Engineering multicomponent nanomaterials as an electrode with rationalized ordered structures is a promising strategy for fulfilling the high-energy storage needs of supercapacitors (SCs). Even now, the fundamental barrier to utilizing hydroxides/hydroxyl carbonates is their poor electrochemical performance, resulting from the significantly poor electrical conductivity and sluggish charge storage kinetics. Hence, a multilayered structural approach is primarily and successfully used to construct electrodes as one of the efficient approaches. This method has made it possible to develop well-ordered nanostructured electrodes with good performance by taking advantage of tunable approach parameters. Herein, we report the design of multilayered heterostructure porous zinc-nickel nanosheets@nickel flakes hydroxyl carbonates and/or hydroxides integrated with conductive PEDOT fibrous network (i.e., ZnNi@Ni@PEDOT) via facile synthesis methods. The combined hybrid electrode acquires the features of high electrical conductivity from one part and various valance states from another one to develop a well-organized nanosheet/flake/fibrous-like heterostructure with decent mechanical strength, creating robust synergistic results. Thus, the designed binder-free ZnNi@Ni@PEDOT electrode delivers a high areal capacity value of 1050.1 µA h cm-2 at 3 mA cm-2 with good cycling durability, significantly outperforming other individual electrodes. Moreover, its feasibility is also tested by constructing a hybrid electrochemical cell (HEC). The assembled HEC exhibits a high areal capacity value of 783.8 µA h cm-2 at 5 mA cm-2, and even at a high current density of 100 mA cm-2 (484.6 µA h cm-2), the device still retains a rate capability of 61.82%. Also, the HEC shows maximum energy and power densities of 0.595 mW h cm-2 and 77.23 mW cm-2, respectively, along with good cycling stability. The obtained energy storage capabilities effectively power various electronic components. These results provide a viable and practical way to construct a positive electrode with innovative heterostructures for high-performance energy storage devices and profoundly influence the development of electrochemical SCs.

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Uncovering the solid-phase conversion mechanism via a new range of organosulfur polymer composite cathodes for lithium-sulfur batteries Xiang Li, Dezhong Liu, Ziyi Cao, Yaqi Liao, Zexiao Cheng, Jie Chen, Kai Yuan, Xing Lin, Zhen Li, Yunhui Huang, Lixia Yuan 2023, 84(9): 459-466.  DOI: 10.1016/j.jechem.2023.05.052 Abstract ( 1 )   PDF (6975KB) ( 1 )   The sulfur cathodes operating via solid phase conversion of sulfur have natural advantages in suppressing polysulfide dissolution and lowering the electrolyte dosage, and thus realizing significant improvements in both cycle life and energy density. To realize an ideal solid-phase conversion of sulfur, a deep understanding of the regulation path of reaction mechanism and a corresponding intentional material and/or cathode design are highly essential. Herein, via covalently fixing of sulfur onto the triallyl isocyanurate, a series of S-triallyl isocyanurate organosulfur polymer composites (STIs) are developed. Relationship between the structure and the electrochemical conversion behavior of STIs is systematically investigated. It is found that the structure of STIs varies with the synthetic temperature, and correspondingly the electrochemical redox of sulfur can be controlled from conventional “solid-liquid-solid” conversion to the “solid-solid” one. Among the STI series, the STI-5 composite realizes an ideal solid-phase conversion and demonstrates great potential for building a Li-S battery with high-energy density and long-cycle-life: it realizes stable cycling over 1000 cycles in carbonate electrolyte, with a degradation rate of 0.053% per cycle; the corresponding pouch cell shows almost no capacity decay for 125 cycles under the conditions of high sulfur loading (4.5 mg cm-2) and lean electrolyte (8 μL mgs-1). In addition, the tailoring strategy of STI can also apply to other precursors with allyl functional groups to develop new organosulfur polymers for “solid-solid” sulfur cathodes. The vulcanized triallyl phosphate (STP) and triallylamine (STA) both show great lithium storage potential. This strategy successfully develops a new family of organosulfur polymers as cathodes for Li-S batteries via solid-phase conversion of sulfur, and brings insights to the mechanism study in Li-S batteries.

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Multiscale strain alleviation of Ni-rich cathode guided by in situ environmental transmission electron microscopy during the solid-state synthesis Fengyu Zhang, Yunna Guo, Chenxi Li, Tiening Tan, Xuedong Zhang, Jun Zhao, Ping Qiu, Hongbing Zhang, Zhaoyu Rong, Dingding Zhu, Lei Deng, Zhangran Ye, Zhixuan Yu, Peng Jia, Xiang Liu, Jianyu Huang, Liqiang Zhang 2023, 84(9): 467-475.  DOI: 10.1016/j.jechem.2023.05.027 Abstract ( 0 )   PDF (11406KB) ( 0 )   Ni-rich layered oxides are one of the most promising cathode materials for Li-ion batteries due to their high energy density. However, the chemomechanical breakdown and capacity degradation associated with the anisotropic lattice evolution during lithiation/delithiation hinders its practical application. Herein, by utilizing the in situ environmental transmission electron microscopy (ETEM), we provide a real time nanoscale characterization of high temperature solid-state synthesis of LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode, and unprecedentedly reveal the strain/stress formation and morphological evolution mechanism of primary/secondary particles, as well as their influence on electrochemical performance. We show that stress inhomogeneity during solid-state synthesis will lead to both primary/secondary particle pulverization and new grain boundary initiation, which are detrimental to cathode cycling stability and rate performance. Aiming to alleviate this multiscale strain during solid-state synthesis, we introduced a calcination scheme that effectively relieves the stress during the synthesis, thus mitigating the primary/secondary particle crack and the detrimental grain boundaries formation, which in turn improves the cathode structural integrity and Li-ion transport kinetics for long-life and high-rate electrochemical performance. This work remarkably advances the fundamental understanding on mechanochemical properties of transition metal oxide cathode with solid-state synthesis and provides a unified guide for optimization the Ni-rich oxide cathode.

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Multidimensional defects tailoring local electron and Mg2+ diffusion channels for boosting magnesium storage performance of WO3/MoO2 Shiqi Ding, Yuxin Tian, Jiankang Chen, He Lv, Amin Wang, Jingjie Dai, Xin Dai, Lei Wang, Guicun Li, Alan Meng, Zhenjiang Li 2023, 84(9): 476-485.  DOI: 10.1016/j.jechem.2023.05.010 Abstract ( 5 )   PDF (11654KB) ( 4 )   Defect engineering presents great promise in addressing lower specific capacity, sluggish diffusion kinetics and poor cycling life issues in energy storage devices. Herein, multidimensional (0D/2D/3D) structural defects are constructed in WO3/MoO2 simultaneously via competing for and sharing with O atoms during simple hydrothermal process. 0D and 2D defects tailor local electron, activating more sites and generating built-in electric fields to yield ion reservoir, meanwhile, 3D defect owning lower anisotropic property tailors Mg2+ diffusion channels to fully exploit Mg2+ adsorbed sites induced by 0D and 2D defects, enhance the kinetics and maintain structural stability. Benefitted from synergistic effect of 0D/2D/3D structural defects, the designed WO3/MoO2 shows the higher specific capacity (112.8 mA h g-1 at 50 mA g-1 with average attenuation rate per cycle of 0.068%), superior rate capability and excellent cycling stability (specific capacity retention of 80% after 1500 cycles at 1000 mA g-1). This strategy provides design ideas of introducing multidimensional structural defects for tailoring local electron and microstructure to improve energy storage property.

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Microbial synthesis of N, P co-doped carbon supported PtCu catalysts for oxygen reduction reaction Shaohui Zhang, Suying Liu, Jingwen Huang, Haikun Zhou, Xuanzhi Liu, Pengfei Tan, Haoyun Chen, Yili Liang, Jun Pan 2023, 84(9): 486-495.  DOI: 10.1016/j.jechem.2023.05.036 Abstract ( 8 )   PDF (5975KB) ( 3 )   Developing highly efficient and stable platinum-based electrocatalyst for oxygen reduction reaction (ORR) is critical to expediting commercialization of fuel cells. Herein, several PtCu alloy nanocatalysts supported on N, P co-doped carbon (PtCu/NPC) were prepared by microbial-sorption and carbonization-reduction. Among them, PtCu/NPC-700 °C exhibits excellent catalytic performance for ORR with a mass activity of 0.895 A mgPt-1 (@0.9 V) which is 8.29 folds of commercial Pt/C. Additionally, the ECSA and MA of PtCu/NPC-700 °C only decrease by 14.2% and 18.7% respectively, while Pt/C decreases by 35.2% and 52.8% after 10,000 cycles of ADT test. Moreover, the PtCu/NPC-700 °C catalyst emanates a maximum power density of 715 mW cm-2 and only 11.1% loss of maximum power density after 10,000 ADTs in single-cell test, indicating PtCu/NPC-700 °C also manifests higher activity and durability in actual single-cell operation than Pt/C. This research provides an easy and novel strategy for developing highly active and durable Pt-based alloy catalyst.

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Efficient thermal management and all-season energy harvesting using adaptive radiative cooling and a thermoelectric power generator Chanil Park, Woohwa Lee, Choyeon Park, Sungmin Park, Jaeho Lee, Yong Seok Kim, Youngjae Yoo 2023, 84(9): 496-501.  DOI: 10.1016/j.jechem.2023.05.051 Abstract ( 11 )   PDF (4008KB) ( 12 )   Passive daytime radiative cooling (PDRC) is useful for thermal management because it allows an object to emit terrestrial heat into space without the use of additional energy. To produce sub-ambient temperatures under direct sunlight, PDRC materials are designed to reduce their absorption of solar energy and to enhance their long-wavelength infrared (LWIR) emissivity. In recent years, many photonic structures and polymer composites have been studied to improve the cooling system of buildings. However, in cold weather (i.e., during winter in cold climates), buildings need to be kept warm rather than cooled due to heat loss. To overcome this limitation, temperature-responsive radiative cooling is a promising alternative. In the present study, adaptive radiative cooling (ARC) film fabricated from a polydimethylsiloxane/hollow SiO2 microsphere/thermochromic pigment composite was investigated. We found that the ARC film absorbed solar radiation under cold conditions while exhibiting radiative cooling at ambient temperatures above 40 °C. Thus, in outdoor experiments, the ARC film achieved sub-ambient temperatures and had a theoretical cooling power of 63.2 W/m2 in hot weather. We also demonstrated that radiative cooling with an energy harvesting system could be used to improve the energy management of buildings, with the thermoelectric module continuously generating output power using the ARC film. Therefore, we believe that our proposed ARC film can be employed for efficient thermal management of buildings and all-season energy harvesting in the near future.