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2019, Vol. 28, No. 1　Online: 2019-01-15


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CO₂ likes molten salts: Capture and in-situ electro-splitting of CO₂ in molten salts integrates carbon reduction with preparation of advanced carbon/oxygen and desulfurization/denitration

In this manuscript, Prof. Xiao and coworkers introduced the basic concepts, possible reactions and morphological variations of the derived carbon. The inert anode materials, cost estimation and scale-up evaluation of the process were also discussed. This strategy is apt to power plants and steel/iron-making sectors, by providing a closed-loop solution in energy, resource and environmental sustainability. With input of electricity from renewable energy and flue gas, advanced carbon and value-added O₂ are generated. The former is the key-enabling material for diverse applications ranging from energy storage/conversion to environmental remediation. The latter, O₂, can be fed back to combustion chambers for high-efficiency oxy-fuel combustion or back to blast furnaces in steel/ironmaking sectors for purifying steel/iron.

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Preface

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One-pot hydrothermal fabrication of α-Fe2O3@C nanocomposites for electrochemical energy storage Maiyong Zhu, Jiarui Kan, Jianmei Pan, Wenjie Tong, Qi Chen, Jiacheng Wang, Songjun Li 2019, 33(1): 1-8.  DOI: 10.1016/j.jechem.2017.09.021 摘要 ( 838 )   A facile hydrothermal method was developed for the preparation of Fe2O3@C nanocomposites using FeCl3·6H2O as iron source and glucose as carbon source under alkaline condition. The morphology and structure of the as-prepared product were identified by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The as-prepare α-Fe2O3@C nanocomposites were employed for supercapacitor electrode material. The synergistic combination of carbon electrical double-layer capacitance and α-Fe2O3 pseudo-capacitance established such nanocomposites as versatile platform for high performance supercapacitors. The synthesis method developed here is expected to obtain other metal oxide/carbon composite.

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Fischer-Tropsch synthesis using Co and Co-Ru bifunctional nanocatalyst supported on carbon nanotube prepared via chemical reduction method Jafar Shariati, Ali Haghtalab, Amir Mosayebi 2019, 33(1): 9-22.  DOI: 10.1016/j.jechem.2017.10.001 摘要 ( 519 )   We used a chemical reduction method to synthesize the catalysts of cobalt (Co) and cobalt-ruthenium (Co-Ru) bifunctional supported on carbon nanotubes (CNTs) for Fischer-Tropsch synthesis (FTS) in a fixedbed reactor. These Co-Ru/CNTs catalysts were synthesized with various weight proportions of Ru/Co (0.1 to 0.4 wt%) with keeping a fixed amount of cobalt (10 wt%). Moreover, for comparison purpose, CNTs supported Co-and Co (Ru)-based catalysts at same loading as the above catalysts were prepared through impregnation method. We characterize the present catalysts through the various techniques such as Energy-dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET), Hydrogen-Temperature-Programmed Reduction (H2-TPR), Hydrogen-Temperature-Programmed Desorption (H2-TPD) and O2 titration. Thus using the chemical reduction method, a narrow particle size distribution was obtained so that the small cobalt particles were confined inside the CNTs. The Co-based catalyst prepared by impregnation was compared with the Co-Ru catalysts at the same loading. The results demonstrated that the use of chemical reduction method led to decrease the average Co oxide cluster size to 8.7 nm so that the reduction enhanced about 24% and stabilized an earlier time at the stream. Among the prepared catalysts, the results indicated that the Co-Ru/CNTs catalysts demonstrated high catalytic activity with the highest long-chain hydrocarbons (C5+), selectivity up to 74.76%, which was higher than those we obtained by the Co-Ru/γ-Al2O3 (61.20%), Co/CNTs (43.68%) and Co/γ-Al2O3 (37.69%). At the same time, comparing with those catalyst synthesized by impregnation, the use of chemical reduction led to enhancement of the C5+ selectivity from 59.30% to 68.83% and increment in FTS rate about 11% for the Co-Ru/CNTs catalyst.

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Effect of preparation method on the bimetallic NiCu/SAPO-11 catalysts for the hydroisomerization of n-octane Zhichao Yang, Yunqi Liu, Yanpeng Li, Lingyou Zeng, Zhi Liu, Xueying Liu, Chenguang Liu 2019, 33(1): 23-30.  DOI: 10.1016/j.jechem.2017.10.003 摘要 ( 741 )   The bimetallic NiCu/SAPO-11 catalysts were prepared by co-impregnation, sequential impregnation, coprecipitation, and mechanical mixing methods. Powder X-ray diffraction, nitrogen adsorption-desorption, temperature-programmed desorption of ammonia, transmission electron microscopy, temperatureprogrammed reduction of hydrogen, and X-ray photoelectron spectroscopy were used to characterize the physicochemical properties of the catalysts. The catalytic performance of the catalysts was assessed by the hydroisomerization of n-octane. Results indicated that the conversion of n-octane and selectivity to n-octane isomers were related to the preparation methods of the catalysts. The catalysts with Ni-Cu alloy effectively restrained the hydrogenolysis reaction that decreases the selectivity of isomerization. The catalyst prepared by the mechanical mixing of NiO and CuO hardly formed Ni-Cu alloy, showing obvious hydrogenolysis and low selectivity to n-octane isomers. The unbalance between the metal and acid sites resulted in the low conversion of n-octane and selectivity to n-octane isomers. Among all the catalysts, the catalyst prepared by the co-impregnation method exhibited high catalytic activity and selectivity to n-octane isomers.

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Sulfur-resistant methanation over MoO3/CeO2-ZrO2 catalyst: Influence of Ce-addition methods Zhaopeng Liu, Yan Xu, Zhenhua Li, Baowei Wang, Weihan Wang, Xinbin Ma, Renjie Liu 2019, 33(1): 31-38.  DOI: 10.1016/j.jechem.2017.10.008 摘要 ( 599 )   PDF(14KB) ( 5 )   In this paper, Ce0.2Zr0.8O2 composite supports were prepared by different Ce-addition methods including impregnation of cerium (CeZr-imp), impregnation of citric acid and cerium (CeZr-CA) simultaneously and deposition precipitation method (CeZr-DP), respectively. The as-prepared supports were applied to prepare 10 wt% MoO3/Ce0.2Zr0.8O2 catalysts for sulfur-resistant methanation. The N2 adsorption/desorption, X-ray diffraction (XRD), Raman spectroscopy (RS), X-ray photoelectron (XPS), temperature-programmed reduction by hydrogen (H2-TPR) were undertaken to get textural properties, morphological information and structures of the catalysts. The results showed that MoO3 was highly dispersed on the surface of these three supports and Ce was mostly of coexisted in Ce4+/Ce3+ redox pairs. Compared with Mo/CeZrimp, the CO conversion increased by 10% and 15% for Mo/CeZr-CA and Mo/CeZr-DP, respectively. This was mainly attributed to the larger specific surface area, Ce3+ concentration and content of active MoS2 on the surface of catalysts.

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Effect of poly(ethylene glycol) molecular weight on CO2/N2 separation performance of poly(amide-12-b-ethylene oxide)/poly(ethylene glycol) blend membranes Shichao Feng, Jizhong Ren, Dan Zhao, Hui Li, Kaisheng Hua, Xinxue Li, Maicun Deng 2019, 33(1): 39-45.  DOI: 10.1016/j.jechem.2017.10.014 摘要 ( 609 )   PDF(15KB) ( 0 )   Membranes from block copolymer poly (amide-12-b-ethylene oxide) (Pebax1074) and its blends with different molecular weight poly (ethylene glycol) (PEG) (200, 400, 600, 1500, 4600 and 8000) were prepared. The thermal properties and structures of Pebax1074/PEG blend membranes were characterized by DSC and SEM, and the gas permeation properties of CO2 and N2 were also investigated at different temperatures. For Pebax1074/PEG blend membranes with low molecular weight PEG (MW ≤ 600), higher gas permeabilities than Pebax1074 were achieved. The permeability increased with the increase of PEG molecular weight. The addition of low molecular weight PEG resulted in decrease in activation energy of permeation. For Pebax1074/PEG blend membranes with high molecular weight PEG (MW ≥ 1500), due to the melt of PEO phase crystals, the gas permeation properties of blend membranes were temperaturedependent, which could be divided into crystalline region, transition region and amorphous region according to two different transition temperatures. PEG molecular weight and operation temperature determined different gas permeation properties of Pebax1074/PEG blend membranes in three regions. The activation energies of permeation in crystalline region were larger than those in amorphous region.

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Catalytic effect of SrTiO3 on the hydrogen storage behaviour of MgH2 M. S. Yahya, M. Ismail 2019, 33(1): 46-53.  DOI: 10.1016/j.jechem.2017.10.020 摘要 ( 565 )   PDF(20KB) ( 1 )   The effects of SrTiO3 on the hydrogen storage properties of MgH2 have been studied for the first time. The onset dehydrogenation temperature of the MgH2-10 wt% SrTiO3 is found to be 275℃, which is 55℃ lower as compared to the as-milled MgH2. The composite is able to absorb 4.3 wt% of hydrogen in 60 min instead of 1.1 wt% for the as-milled MgH2. Meanwhile, the composite is able to release 5.3 wt% of hydrogen in 17 min compared to 1.9 wt% by the as-milled MgH2 at 320℃. The calculated Ea of the MgH2-10 wt% SrTiO3 is 109 kJ/mol, which is 26.3 kJ/mol lower than the calculated Ea of the as-milled MgH2. The SrTiO3 is not decomposed during the ball milling and the re/dehydrogenation processes. The catalytic effect shown by the SrTiO3 is owing to its ability to change the physical structure of the MgH2 particles during the ball milling process.

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An imine-linked covalent organic framework as the host material for sulfur loading in lithium-sulfur batteries Jianyi Wang, Liping Si, Qin Wei, Xujia Hong, Ligui Lin, Xin Li, Jingyi Chen, Peibiao Wen, Yuepeng Cai 2019, 33(1): 54-60.  DOI: 10.1016/j.jechem.2017.10.021 摘要 ( 718 )   PDF(17KB) ( 7 )   Lithium-sulfur (Li-S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework (COF) as a new porous crystalline material has been used as the host material in Li-S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading (60%) in Li-S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability (up to 500℃). In the electrochemical experiment, the performance of the composite cathode with acetylene black (AB) and super-P (S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g, the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li-S battery.

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Analysis of CO2 utilization into synthesis gas based on solar thermochemical CH4-reforming Bachirou Guene Lougou, Yong Shuai, Gédéon Chaffa, Huang Xing, Heping Tan, Huibin Du 2019, 33(1): 61-72.  DOI: 10.1016/j.jechem.2018.01.011 摘要 ( 762 )   PDF(12KB) ( 0 )   In this study, the solar thermochemical reactor performance for CO2 utilization into synthesis gas (H2 + CO) based on CH4 reforming process was investigated in the context of carbon capture and utilization (CCU) technologies. The P1 radiation heat transfer model is adopted to establish the heat and mass transfer model coupled with thermochemical reaction kinetics. The reactor thermal behavior with direct heat transfer between gaseous reactant and products evolution and the effects of different structural parameters were evaluated. It was found that the reactor has the potential to utilize by~60% of CO2 captured with 40% of CH4 co-fed into syngas (72.9% of H2 and 27.1% of CO) at 741.31 kW/m2 of incident radiation heat flux. However, the solar irradiance heat flux and temperature distribution were found to significantly affect the reactant species conversion efficiency and syngas production. The chemical reaction is mainly driven by the thermal energy and higher species conversion into syngas was observed when the temperature distribution at the inner cavity of the reactor was more uniform. Designed a solar thermochemical reactor able to volumetric store concentrated irradiance could highly improve CCU technologies for producing energy-rich chemicals. Besides, the mixture gas inlet velocity, operating pressure and CO2/CH4 feeding ratio were crucial to determining the efficiency of CO2 utilization to solar fuels. Catalytic CO2-reforming of CH4 to chemical energy is a promising strategy for an efficient utilization of CO2 as a renewable carbon source.

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Highly efficient electrocatalysts derived from carbon black supported non-precious metal macrocycle catalysts for oxygen reduction reaction Lijie Hou, Jianing Guo, Zhonghua Xiang 2019, 33(1): 73-78.  DOI: 10.1016/j.jechem.2018.01.010 摘要 ( 700 )   PDF(16KB) ( 0 )   For the sake of accelerating the commercial application of fuel cells, non-noble metal catalysts with high activity and high stability have been widely developed to replace platinum-based catalysts. Here, we report a simple but cost-effective synthetic strategy using iron tetra-amino phthalocyanine (FePC-NH2) and modified carbon black (HCB) to obtain a novel oxygen reduction electrocatalyst (named as FePC-NH2/HCB-800) with Fe2O3 wrapped in nitrogen-doped carbon (N-carbon) as active site. The HCB as template can effectively promotes the formation of Fe2O3 active site in the catalysts. Compared to commercial Pt/C catalyst, the FePC-NH2/HCB-800 catalyst exhibits high electrocatalytic activity for oxygen reduction reaction (ORR) with onset potential of 0.98 V and half-wave potential with 0.84 V vs. reversible hydrogen electrode (RHE). Meanwhile, the catalyst also shows excellent circulation stability. We believe that this work provides a platform for ORR and is conducive to the commercialization of fuel cells and metal-air batteries.

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Fabricating high-performance sodium ion capacitors with P2-Na0.67Co0.5Mn0.5O2 and MOF-derived carbon Haichen Gu, Lingjun Kong, Huijuan Cui, Xianlong Zhou, Zhaojun Xie, Zhen Zhou 2019, 33(1): 79-84.  DOI: 10.1016/j.jechem.2018.01.012 摘要 ( 747 )   PDF(17KB) ( 6 )   Sodium ion capacitors (SICs) have been considered as a kind of promising devices to achieve both high power and energy density. However, it is still a challenge to achieve high energy output at elevated power delivery due to the poor rate capability of battery-type electrode materials and the kinetic mismatch with capacitor-type electrode materials. In this work, to fabricate SICs, P2-Na0.67Co0.5Mn0.5O2 (P2-NCM) was chosen as the battery-type cathode material, and a typical metal-organic framework (MOF) material, zeolitic imidazolate framework-8 (ZIF-8) derived carbon (ZDC) was utilized as the capacitor-type anode material. Due to the kinetic match and high-rate performance of both electrodes, the ZDC//P2-NCM SICs exhibited an energy output of 18.8 Wh kg-1 at a high power delivery of 12.75 kW kg-1.

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The effect of rosin acid on hydrodeoxygenation of fatty acid Houman Ojagh, Derek Creaser, Muhammad Abdus Salam, Eva Lind Grennfelt, Louise Olsson 2019, 33(1): 85-94.  DOI: 10.1016/j.jechem.2018.01.023 摘要 ( 701 )   PDF(14KB) ( 1 )   In this study, inhibition of tall oil fatty acid hydrodeoxygenation (HDO) activity due to addition of rosin acid over sulfided NiMo/Al2O3 was investigated. Oleic acid and abietic acid were used as model compounds for fatty acid and rosin acid respectively in tall oil. After completion of each HDO experiment, the NiMo catalysts were recovered and used again under the same conditions. The results showed that the oleic acid HDO activity of sulfided catalysts was inhibited by addition of abietic acid due to competitive adsorption and increased coke deposition. The rate of carbon deposition on the catalysts increased when abietic acid was added to oleic acid feed. Moreover, the coke was in a more advanced form with higher stability for the catalysts exposed to both oleic acid and abietic acid. Furthermore, a clear correlation between the rate of coke formation and concentration of abietic acid was observed.

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EDTA-assisted hydrothermal synthesis of flower-like CoSe2 nanorods as an efficient electrocatalyst for the hydrogen evolution reaction Yanghui Deng, Cui Ye, Guo Chen, Baixiang Tao, Hongqun Luo, Nianbing Li 2019, 33(1): 95-100.  DOI: 10.1016/j.jechem.2018.01.022 摘要 ( 731 )   Hydrogen evolution reaction (HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future. CoSe2, one of the earth-abundant electrocatalysts, has been proved to be a promising catalyst for hydrogen generation. In our work, flower-like CoSe2 nanorods with high quality are successfully synthesized through a facile ethylenediaminetetraacetic acid ligand (EDTA)-assisted hydrothermal process. The flower-like CoSe2 nanorods show the brilliant electrochemical HER performance with 100 mA cm-2 at overpotential of 273 mV, a small Tafel slope of 35 mV dec-1 and strong durability in acid solution. The sparkly HER catalytic activity of CoSe2 can be ascribed to its particular structure with large surface area and abundant active sites. Therefore, this work offers an outstanding candidate for improving hydrogen production capabilities by water electrolysis.

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Efficient one-pot hydrogenolysis of biomass-derived xylitol into ethylene glycol and 1,2-propylene glycol over Cu-Ni-ZrO2 catalyst without solid bases Shenglin Li, Yifan Zan, Yuanyuan Sun, Zhichao Tan, Gai Miao, L. Z. Kong, Yuhan Sun 2019, 33(1): 101-106.  DOI: 10.1016/j.jechem.2018.01.021 摘要 ( 668 )   PDF(13KB) ( 2 )   The directly selective hydrogenolysis of xylitol to ethylene glycol (EG) and 1,2-propylene glycol (1,2-PDO) was performed on Cu-Ni-ZrO2 catalysts prepared by a co-precipitation method. Upon optimizing the reaction conditions (518 K, 4.0 MPa H2 and 3 h), 97.0% conversion of xylitol and 63.1% yield of glycols were obtained in water without extra inorganic base. The catalyst still remained stable activity after six cycles and above 80% total selectivity of glycols was obtained when using 20.0% xylitol concentration. XRD, TEM and ICP results indicated that Cu-Ni-ZrO2 catalysts possess favorable stability. Cu and Ni are beneficial to the cleavage of C-O and C-H bond, respectively. To reduce the hydrogen consumption, isopropanol was added as in-situ hydrogen source and 96.4% conversion of xylitol with 43.6% yield of glycols were realized.

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Solution processed nano-ZnMgO interfacial layer for highly efficient inverted perovskite solar cells Ze Wang, Yingdong Xia, Lingfeng Chao, Yufeng Pan, Meijin Li, Renzhi Li, Bin Du, Yonghua Chen, Wei Huang 2019, 33(1): 107-110.  DOI: 10.1016/j.jechem.2018.03.001 摘要 ( 652 )   PDF(17KB) ( 4 )   Interfacial layer has a significant impact on the achievement of highly efficient organic-inorganic hybrid perovskite solar cells (PSCs). Here, we introduced a nano-ZnMgO (magnesium doped ZnO, abbreviated as ZnMgO) as interfacial layer between[6, 6]-Phenyl C61 butyric acid methyl ester (PC61 BM) layer and Al electrode to replace LiF or ZnO interlayer and enhance device performance. The device efficiency has been improved from 11.43% to 15.61% and the hysteresis was decreased dramatically. Such huge enhancement of power convert efficiency (PCE) can be attributed to the low dark current density, enhancement of electron-selective contact, and low energy barrier at the PC61 BM/Al interface. We suggest that this simple nano-scale interlayer can provide an efficient charge transport and extraction for highly efficient PSCs.

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One-pot synthesis of Ag-rich AgPd alloy nanoactiniae and their enhanced electrocatalytic activity toward oxygen reduction Xiaoyu Qiu, Xiaohong Yan, Ke Cen, Huaifang Zhang, Geng Gao, Liangjun Wu, Dongmei Sun, Yawen Tang 2019, 33(1): 111-117.  DOI: 10.1016/j.jechem.2018.02.012 摘要 ( 646 )   PDF(15KB) ( 2 )   The electro-catalytic properties can be effectively optimized by designing bimetallic alloy nanoparticles with high-content less-active metal to enhance the competence of more-active noble metal. Herein, a one-pot hydrothermal approach is demonstrated for the controllable synthesis of Ag-rich Ag9Pd1 alloy nanoactiniae with obviously enhanced electro-catalytic activity (2.23 mA cm-2 at 0.85 V) and stability for oxygen reduction reaction. In alkaline solution, the ORR onset potential and half-wave potential of the Ag9Pd1 alloy nanoactiniae can reach a value of 1.02 V and 0.89 V, respectively, which origin from strong ligand and ensemble effects between Pd element and Ag element. The nanocrystals are uniformly alloyed, displaying a Ag9Pd1 combination, as displayed by an assembly of X-ray diffraction (XRD) spectrum, energy dispersive X-ray (EDX) analysis, and cyclic voltammetry (CV). This concept of tuning bimetallic alloy nanocrystals with low concentrations of more precious metal may be a promising approach to be applicable to a wide range of alloy nanocrystals.

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Low-temperature synthesis of nitrogen doped carbon nanotubes as promising catalyst support for methanol oxidation Liang Liang, Meiling Xiao, Jianbing Zhu, Junjie Ge, Changpeng Liu, Wei Xing 2019, 33(1): 118-122.  DOI: 10.1016/j.jechem.2018.04.003 摘要 ( 784 )   PDF(21KB) ( 0 )   The electrochemical methanol oxidation reaction (MOR) is of paramount importance for direct methanol fuel cell (DMFC) application, where efficient catalysts are required to facilitate the complicated multiple charge transfer process. The catalyst support not only determines the dispersion status of the catalysts particles, but also exerts great influence on the electronic structure of the catalysts, thereby altering its intrinsic activity. Herein, we demonstrated that nitrogen atoms, assisted by the pre-treatment of carbon matrix with oxidants, can be easily doped into carbon nanotubes at low temperature. The obtained nitrogen-doped carbon nanotubes can effectively improve the dispersion of the supported platinum nanoparticles and facilitate the MOR by modifying the electronic structure of platinum atoms, through catalyst-support interaction.

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Enhanced hydrogen evolution reaction over molybdenum carbide nanoparticles confined inside single-walled carbon nanotubes Tingting Cui, Jinhu Dong, Xiulian Pan, Tie Yu, Qiang Fu, Xinhe Bao 2019, 33(1): 123-127.  DOI: 10.1016/j.jechem.2018.03.006 摘要 ( 657 )   PDF(18KB) ( 1 )   Carbon nanotubes (CNTs) have shown as unique nanoreactors to tune the catalytic activity of confined nano-catalysts. Here we report that the catalytic performance of molybdenum carbide nanoparticles (MoCx NPs) for the hydrogen evolution reaction (HER) process can be enhanced by encapsulation within single-walled carbon nanotubes (SWNTs) with a diameter of 1-2 nm. The catalyst with MoCx NPs located on the interior surface of SWNTs (MoCx@SWNTs) exhibits a lower onset over-potential and a smaller Tafel slope than the one with MoCx NPs attached on the exterior surface (MoCx/SWNTs). This is likely attributed to the much smaller particle size and the more reduced states of the confined MoCx NPs, as well as the larger specific surface area of MoCx@SWNTs compared with MoCx/SWNTs. In addition, the electronic structure of the confined MoCx NPs might be modified by the confinement effects of SWNTs, and hence the adsorption free energy of H atoms on the confined MoCx NPs, which could also contribute to their higher performance. These results suggest that the SWNTs can be further explored for constructing novel catalysts with beneficial catalytic performance.

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Capture and electro-splitting of CO2 in molten salts Wei Weng, Lizi Tang, Wei Xiao 2019, 33(1): 128-143.  DOI: 10.1016/j.jechem.2018.06.012 摘要 ( 845 )   PDF(16KB) ( 19 )   Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO2, carbon capture and storage (CCS) has been an important area of research and many technologies are developed within this field. Molten salt CO2 capture and electrochemical transformation (MSCC-ET) process is a desirable method due to a high CO2 solubility, a wide potential window of molten salts and easily-controlled electrode reactions. Generally, electro-splitting CO2 in molten salts begins with CO2 absorption reactions to form CO32-, which is then followed by the carbon deposition at the cathode and O2 evolution at the anode. As a result, CO2 is electro-converted to O2 and carbon with different morphologies, compositions, microstructures and functional properties. This report introduces the MSCC-ET process, summarizes the reactions occurring in the molten salts and at the electrode surfaces, as well as the morphological variations of the cathodic products. The inert anode materials, cost estimation and scale-up evaluation of the process are then discussed. It is presumed that with a comprehensive understanding of the electrode reactions during electrolysis and the functional properties of carbon materials obtained during CO2 electro-splitting can provide a foundation for further developing this environmentally friendly process.

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3D skeleton nanostructured Ni3S2/Ni foam@RGO composite anode for high-performance dual-ion battery Shuai Wang, Jiguo Tu, Jiusan Xiao, Jun Zhu, Shuqiang Jiao 2019, 33(1): 144-150.  DOI: 10.1016/j.jechem.2018.07.010 摘要 ( 745 )   The growing global demands of safe, low-cost and high working voltage energy storage devices trigger strong interests in novel battery concepts beyond state-of-art lithium-ion battery. Herein, a dualion battery based on nanostructured Ni3S2/Ni foam@RGO (NSNR) composite anode is developed, utilizing graphite as cathode material and LiPF6-VC-based solvent as electrolyte. The battery operates at high working voltage of 4.2-4.5 V, with superior discharge capacity of~90 mA h g-1 at 100 mA g-1, outstanding rate performance, and long-term cycling stability over 500 cycles with discharge capacity retention of~85.6%. Moreover, the composite simultaneously acts as the anode material and the current collector, and the corrosion phenomenon can be greatly reduced compared to metallic Al anode. Thus, this work represents a significant step forward for practical safe, low-cost and high working voltage dual-ion batteries, showing attractive potential for future energy storage application.

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TiP2O7-coated LiNi0.8Co0.15Al0.05O2 cathode materials with improved thermal stability and superior cycle life Guan Wu, Yingke Zhou 2019, 33(1): 151-159.  DOI: 10.1016/j.jechem.2018.01.018 摘要 ( 549 )   The co-precipitation derived LiNi0.8Co0.15Al0.05O2 cathode material was modified by a coating layer of TiP2O7 through an ethanol-based process. The TiP2O7-coated LiNi0.8Co0.15Al0.05O2 is characterized by X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy to investigate the microstructure and morphology. The differential scanning calorimetry was employed to confirm the improved thermal stability. The electrochemical properties were evaluated by the constant-current charge/discharge tests. The TiP2O7 coating layer is effectively suppressing the structural degradation and ameliorating the surface status of LiNi0.8Co0.15Al0.05O2 particles, and the intrinsic rhombohedral layered structure of TiP2O7-coated LiNi0.8Co0.15Al0.05O2 was well maintained during the long-term cycling process, while the surface structure of pristine LiNi0.8Co0.15Al0.05O2 was degraded from rhombohedral R3m layered structure to cubic rock-salt structure. The charged state Ni4+ ions will easily transform into Ni2+ when the electrolytes oxidized at the interface of cathode/electrolytes and formed the cubic rock-salt NiO type structure, and the cubic rock-salt structure without electrochemical activity on the surface of LiNi0.8Co0.15Al0.05O2 particles will finally accelerate capacity fading. The thermal stability and cyclic performances of the LiNi0.8Co0.15Al0.05O2 electrode were remarkably improved by TiP2O7 coating, the total amount of heat release corresponding to the intensity of thermal runaway were 1075.5 and 964.6 J/g for pristine LiNi0.8Co0.15Al0.05O2 and TiP2O7-coated LiNi0.8Co0.15Al0.05O2 respectively, the pouch shaped full cells that employed TiP2O7-coated LiNi0.8Co0.15Al0.05O2 as cathode were able to perform more than 2200 cycles at 25℃ and more than 1000 cycles at 45℃ before the capacity retention fading to 80%.