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过刊目录

    2019, Vol. 33, No. 6 Online: 2019-06-15
    全选选: 隐藏/显示图片
    Preface
    Facile oxalic acid-assisted construction of laminated porous Ndeficient graphitic carbon nitride: Highly efficient visible-lightdriven hydrogen evolution photocatalyst
    Fengli Yang, Jia Ren, Qianqian Liu, Lu Zhang, Yuanyuan Chai, Wei-Lin Dai
    2019, 28(6): 1-8.  DOI: 10.1016/j.jechem.2018.08.002
    摘要 ( 37 )  
    The laminated porous N-deficient g-C3N4 (CN-H) is successfully synthesized by a facile two-step hydrothermal calcination method using oxalic acid-assisted melamine as the precursor. Compared with pristine g-C3N4 (224 μmol g-1 h-1), the CN-H shows superior photocatalytic hydrogen production activity (up to 728 μmol g-1 h-1), which is three times higher than the unmodified counterpart. To draw out the multifaceted influences of oxalic acid modification on the visible-light-induced photocatalytic activity, various techniques are utilized to investigate the formation mechanism, structural characteristics and photoelectrical properties of CN-H. The results indicate that the addition of a trace amount of oxalic acid to the precursor melamine results in a g-C3N4 structure possessing the advantage of both nitrogen defects and laminated porosity. These properties can enlarge specific surface areas of g-C3N4, enhance an efficient separating of photogenerated electron-hole pairs and extend the range of spectral response, all contributing to the enhancement of the visible-light-induced photocatalytic activity.
    Understanding the roles of Ti on the structure and electrochemical performances of Li2Ru1-xTixO3 cathode materials for Li-ion batteries
    Hu Zhao, Yanchao Shi, Li Xue, Yingzhi Cheng, Zhongbo Hu, Xiangfeng Liu
    2019, 28(6): 9-16.  DOI: 10.1016/j.jechem.2018.08.008
    摘要 ( 42 )  
    The lattice doping has been widely used to improve the electrochemical performances of Li-rich cathode materials but the roles of the introduced foreign atoms are still not very clear. Herein, a series of Li2Ru1-xTixO3 solid solutions have been synthesized and the roles of Ti doping on the structural and electrochemical properties of Li2RuO3 have been comprehensively investigated. The Rietveld refinement exhibits that the interlayer spacing gradually shortens with increasing Ti content. This shrinkage is favorable to the layered structure stability but increases the lithium diffusion barrier. Galvanostatic measurements show that Li2Ru0.8Ti0.2O3 possesses the best cyclability with 196.9 and 196.1 mAh g-1 for charge and discharge capacity retaining after 90 cycles, respectively. Cyclic voltammetry scanning indicates that Ti dopant promotes the formation of more peroxo- or superoxo-like species but reduces the initial coulumbic efficiency. Results of electrochemical impedance spectroscopy display that Ti doping reduces the charge transfer impedance, which facilitates the lithium-ion diffusion across the electrolyteelectrode interface and improves the electronic conductivity. Li2Ru0.8Ti0.2O3 exhibits the best electrochemical performance owing to the balance among all the factors discussed above. This study also offers some new insights into optimizing the electrochemical performances of Li-rich cathode materials through the lattice doping.
    Study of borohydride ionic liquids as hydrogen storage materials
    Loris Lombardo, Heena Yang, Andreas Züttel
    2019, 28(6): 17-21.  DOI: 10.1016/j.jechem.2018.08.011
    摘要 ( 46 )  
    Stability of borohydrides is determined by the localization of the negative charge on the boron atom. Ionic liquids (ILs) allow to modify the stability of the borohydrides and promote new dehydrogenation pathways with a lower activation energy. The combination of borohydride and IL is very easy to realize and no expensive rare earth metals are required. The composite of the ILs with complex hydrides decreases the enthalpy and activation energy for the hydrogen desorption. The Coulomb interaction between borohydride and IL leads to a destabilization of the materials with a significantly lower enthalpy for hydrogen desorption. Here, we report a simple ion exchange reaction using various ILs, such as vinylbenzyltrimethylammonium chloride ([VBTMA] [Cl]), 1-butyl-3-methylimidazolium chloride ([bmim] [Cl]), and 1-ethyl-1-methylpyrrolidinium bromide ([EMPY] [Br]) with NaBH4 to decrease the hydrogen desorption temperature. Dehydrogenation of 1-butyl-3-methylimidazolium borohydride ([bmim] [BH4]) starts below 100℃. The quantity of desorbed hydrogen ranges between 2.4 wt% and 2.9 wt%, which is close to the theoretical content of hydrogen. The improvement in dehydrogenation is due to the strong amine cation that destabilizes borohydride by charge transfer.
    Electrochemical CO2 reduction over nitrogen-doped SnO2 crystal surfaces
    Yuefeng Zhang, Jianjun Liu, Zengxi Wei, Quanhui Liu, Caiyun Wang, Jianmin Ma
    2019, 28(6): 22-30.  DOI: 10.1016/j.jechem.2018.08.017
    摘要 ( 35 )  
    Crystal planes of a catalyst play crucial role in determining the electrocatalytic performance for CO2 reduction. The catalyst SnO2 can convert CO2 molecules into valuable formic acid (HCOOH). Incorporating heteroatom N into SnO2 further improves its catalytic activity. To understand the mechanism and realize a highly efficient CO2-to-HCOOH conversion, we used density functional theory (DFT) to calculate the free energy of CO2 reduction reactions (CO2RR) on different crystal planes of N-doped SnO2 (N-SnO2). The results indicate that N-SnO2 lowered the activation energy of intermediates leading to a better catalytic performance than pure SnO2. We also discovered that the N-SnO2 (211) plane possesses the most suitable free energy during the reduction process, exhibiting the best catalytic ability for the CO2-to-HCOOH conversion. The intermediate of CO2RR on N-SnO2 is HCOO* or COOH* instead of OCHO*. These results may provide useful insights into the mechanism of CO2RR, and promote the development of heteroatomdoped catalyst for efficient CO2RR.
    Palladium nanoclusters immobilized on defective nanodiamondgraphene core-shell supports for semihydrogenation of phenylacetylene
    Fei Huang, Zhimin Jia, Jiangyong Diao, Hua Yuan, Dangsheng Su, Hongyang Liu
    2019, 28(6): 31-36.  DOI: 10.1016/j.jechem.2018.08.006
    摘要 ( 40 )  
    We report a nanocarbon material with nanodiamond (ND) core and graphene shell (ND@G) as a support for Pd nanocatalysts. The designed catalyst performed good selectivity of styrene (85.2%) at full conversion of phenylacetylene and superior stability under mild conditions. Supported Pd catalysts are characterized by means of high resolution transmission electron microscopy (HRTEM), Raman, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and H2 temperature-programmed reduction (H2-TPR). The results clearly show that formation of the strong metal-support interaction (SMSI) between Pd nanoclusters and the defective graphene shell helpfully modifies the selectivity and stability of the Pd-based catalysts.
    Distinctive electrochemical performance of novel Fe-based Li-rich cathode material prepared by molten salt method for lithium-ion batteries
    Taolin Zhao, Rixin Ji, Hedi Yang, Yuxia Zhang, Xiuguo Sun, Yanting Li, Li Li, Renjie Chen
    2019, 28(6): 37-45.  DOI: 10.1016/j.jechem.2018.08.005
    摘要 ( 44 )  
    For constructing next-generation lithium-ion batteries with advanced performances, pursuit of highcapacity Li-rich cathodes has caused considerable attention. So far, the low discharge specific capacity and serious capacity fading are strangling the development of Fe-based Li-rich materials. To activate the extra-capacity of Fe-based Li-rich cathode materials, a facile molten salt method is exploited using an alkaline mixture of LiOH-LiNO3-Li2O2 in this work. The prepared Li1.09(Fe0.2Ni0.3Mn0.5)0.91O2 material yields high discharge specific capacity and good cycling stability. The discharge specific capacity shows an upward tendency at 0.1 C. After 60 cycles, a high reversible specific capacity of ~250 mAh g-1 is delivered. The redox of Fe3+/Fe4+ and Mn3+/Mn4+ are gradually activated during cycling. Notably, the redox reaction of Fe2+/Fe3+ can be observed reversibly below 2 V, which is quite different from the material prepared by a traditional co-precipitation method. The stable morphology of fine nanoparticles (100-300 nm) is considered benefiting for the distinctive electrochemical performances of Li1.09(Fe0.2Ni0.3Mn0.5)0.91O2. This study demonstrates that molten salt method is an inexpensive and effective approach to activate the extra capacity of Fe-based Li-rich cathode material for high-performance lithium-ion batteries.
    A review of recent researches on Bunsen reaction for hydrogen production via S-I water and H2S splitting cycles
    Ke Zhang, Weiren Bao, Liping Chang, Hui Wang
    2019, 28(6): 46-58.  DOI: 10.1016/j.jechem.2018.08.015
    摘要 ( 71 )  
    The Bunsen reaction is the center reaction for both the sulfur-iodine water splitting cycle for hydrogen production and the novel hydrogen sulfide splitting cycle for hydrogen and sulfuric acid production from the sulfur-containing gases. This paper reviews the research progress of the Bunsen reaction in recent 10-15 years. Researches were initially focused on the optimization of the operating conditions of the conventional Bunsen reaction requiring excessive water and iodine to improve the products separation efficiency and to avoid the side reactions and iodine vapor deposition. Alternative methods including electrochemical methods, precipitation methods, and non-aqueous solvent methods had their respective advantages, but still faced challenges. In development of the technology of H2S splitting cycle, dissolving iodine in toluene solvent could render the Bunsen reaction to occur with the flowable I2 stream at ambient temperature such that the side reactions and iodine vaporization can be avoided and the corrosion hazard lessened. It also prevented the Bunsen reaction from using excessive iodine and water. The products from the Bunsen reaction including HI, H2SO4, H2O, and toluene could be directly electrolyzed.
    Hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets as an efficient bifunctional catalyst for Zn-air battery
    Yuhui Tian, Li Xu, Jian Bao, Junchao Qian, Huaneng Su, Huaming Li, Haidong Gu, Cheng Yan, Henan Li
    2019, 28(6): 59-66.  DOI: 10.1016/j.jechem.2018.08.007
    摘要 ( 40 )  
    Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has been a great significant for metal-air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets (Co/N-Pg) is fabricated for Zn-air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn-air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap (0.81 V at 50 mA cm-2) and high peak power density (119 mW cm-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn-air battery.
    Controlled synthesis of cobalt nanocrystals on the carbon spheres for enhancing Fischer-Tropsch synthesis performance
    Ting Kuang, Shuai Lyu, Sixu Liu, Yuhua Zhang, Jinlin Li, Guanghui Wang, Li Wang
    2019, 28(6): 67-73.  DOI: 10.1016/j.jechem.2018.08.012
    摘要 ( 40 )  
    Non-porous carbon sphere was used as support to synthesize supported cobalt Fischer-Tropsch catalysts with high activity and durability. Strong metal-support interaction was avoided and intrinsic activity of pristine cobalt nano-particles was studied. Thermal decomposition synthesis method was applied to obtain cobalt catalysts with high dispersion and narrow particle size distribution. Furthermore the cobalt size can be controlled by the molar ratio of o-dichlorobenzene/benzylamine. Compared with supported cobalt catalysts prepared by incipient wetness impregnation method and ultrasonic impregnation method, the catalyst prepared by thermal decomposition method showed higher catalytic activity, higher long chain hydrocarbons selectivity and lower methane selectivity.
    Unique NiFe NiCoO2 hollow polyhedron as bifunctional electrocatalysts for water splitting
    Rong Shi, Jiaxin Wang, Zhi Wang, Tengfei Li, Yu-Fei Song
    2019, 28(6): 74-80.  DOI: 10.1016/j.jechem.2018.08.016
    摘要 ( 48 )  
    It is of significance to design of stable and cost-effective electrocatalyst for water splitting with high efficiency in an alkaline medium. The major obstacles for practical application of water splitting devices are lack of high-efficiency and low-cost electrocatalysts with low overpotential for both HER and OER. In this paper, we report a NiFe alloy decorated NiCoO2 hollow polyhedron (denoted as NiFe-NiCoO2) by using[NiFe(CN)6]- intercalated NiCo-LDH as precursor. As evidenced by the electrochemical active surface area, the resultant NiFe-NiCoO2 composite shows unique hollow nanostructure, which can not only provide abundant mass transport channels, but also increase the contact area of the NiFe-NiCoO2 material with the electrolyte. The overpotential (η) demand is 286 mV for OER and 102 mV for HER at the current density of 10 mA/cm2 in an alkaline medium of 1 M KOH for the NiFe/NiCoO2 composite. This work provides a new pathway for preparation of the highly efficient bifunctional electrocatalysts for water splitting.
    Fabrication of lithium silicates from zeolite for CO2 capture at high temperatures
    Yu Zhang, Yanshan Gao, Benoit Louis, Qiang Wang, Weiran Lin
    2019, 28(6): 81-89.  DOI: 10.1016/j.jechem.2018.08.014
    摘要 ( 44 )  
    Li4SiO4 has been regarded as one of the most promising high-temperature CO2 sorbents. However, for practical applications, its CO2 sorption kinetics, cycling stability and sorption properties at lower temperatures or lower CO2 concentrations have to be improved. In this contribution, four Li4SiO4 sorbents were synthesized from zeolite precursors MCM-41, MCM-48, TS-1, and ZSM-5. The CO2 uptake, cycling stability and the optimal CO2 sorption conditions were investigated. Among the samples, MCM-41-Li4SiO4 showed the best cycling stability at 650℃, with a stable reversible CO2 uptake of 29.1 wt% under 100 vol% CO2 during 20 cycles. But its sorption kinetics and CO2 uptakes at lower temperatures and lower CO2 concentrations need to be improved. We then demonstrated that the sorption kinetics can be improved by modifying the MCM-41 precursor with metals such as Al, Ti, Ca, and Na. The Na-MCM-41-Li4SiO4 sample exhibited the highest sorption rate, and reached the equilibrium sorption capacity close to the theoretical value of 36.7 wt% within 20 min. In addition, we proved that coating the MCM-41-Li4SiO4 with Na2CO3 and K2CO3 can significantly increase the CO2 uptakes at lower temperatures (e.g. 550℃) and lower CO2 concentrations (10-20 vol%). At 550℃ and under 20 vol% CO2, 15 wt% K2CO3-MCM-41-Li4SiO4 and 10 wt% Na2CO3-MCM-41-Li4SiO4 sorbents resulted in a CO2 uptake of 32.2 wt% and 34.7 wt%, respectively, which are much higher than that of MCM-41-Li4SiO4 (11.8 wt%). These two sorbents also showed good cycling stability. The promoiting mechasnim by alkali carbonate coating was discussed by a doubleshell model.
    Improving the stability of metal halide perovskite solar cells from material to structure
    Kui Qin, Binghai Dong, Shimin Wang
    2019, 28(6): 90-99.  DOI: 10.1016/j.jechem.2018.08.004
    摘要 ( 37 )  
    Metal halide perovskites (MHPs) are promising photovoltaic (PV) materials owing to their advantages such as high carrier mobility, excellent absorption coefficient, bandgap tenability, long diffusion length, and low material cost. These qualities have increased the efficiency of MHP solar cells to 23.3%. However, MHPs are hindered by a lack of stability. In addition, the applications of MHP solar cells are restricted by the instability of perovskite materials and devices. In this article, the most urgent stability problems faced by perovskite solar cells are identified, and recent progresses in MHPs are enumerated. The factors affecting the stability of perovskite materials and devices are also discussed. We analyzed the thermal and humid stability of perovskite materials in terms of transporting materials and their interface. In view of these recent advances, future works should focus on the large-scale application of MHP solar cells.
    Molybdenum and tungsten chalcogenides for lithium/sodium-ion batteries: Beyond MoS2
    Junda Huang, Zengxi Wei, Jiaqin Liao, Wei Ni, Caiyun Wang, Jianmin Ma
    2019, 28(6): 100-124.  DOI: 10.1016/j.jechem.2018.09.001
    摘要 ( 46 )  
    Molybdenum and tungsten chalcogenides have attracted tremendous attention in energy storage and conversion due to their outstanding physicochemical and electrochemical properties. There are intensive studies on molybdenum and tungsten chalcogenides for energy storage and conversion, however, there is no systematic review on the applications of WS2, MoSe2 and WSe2 as anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), except MoS2. Considering the importance of these contents, it is extremely necessary to overview the recent development of novel layered WS2, MoSe2 and WSe2 beyond MoS2 in energy storage. Here, we will systematically overview the recent progress of WS2, MoSe2 and WSe2 as anode materials in LIBs and SIBs. This review will also discuss the opportunities, and perspectives of these materials in the energy storage fields.
    Electrosynthesis of hierarchical NiLa-layered double hydroxide electrode for efficient oxygen evolution reaction
    Shan Jiang, Yunke Liu, Wenfu Xie, Mingfei Shao
    2019, 28(6): 125-129.  DOI: 10.1016/j.jechem.2018.08.010
    摘要 ( 47 )  
    Oxygen evolution reaction (OER) is a key process for electrochemical water splitting due to its intrinsic large overpotential. Recently, layered double hydroxides (LDHs), especially NiFe-LDH, have been regarded as highly performed electrocatalysts for OER in alkaline condition. Here we first present a new class of NiLa-LDH electrocatalyst synthesized by an electrochemical process for efficient water splitting. The as-prepared NiLa-LDH nanosheet arrays (NSAs) give remarkable electrochemical activity and durability under alkaline environments, with a low overpotential of 209 mV for OER to deliver a current density of 10 mA cm-2, surpassing most of previous reported LDHs eletrocatalysts. The presence of NiLa-LDH in this work extends the studies about LDHs-based electrocatalysts, which will benefit the development of electrochemical energy storage and conversion systems.
    Template-free synthesis of three-dimensional NiFe-LDH hollow microsphere with enhanced OER performance in alkaline media
    Haihong Zhong, Tongyuan Liu, Shuwei Zhang, Dianqing Li, Pinggui Tang, Nicolas Alonso-Vante, Yongjun Feng
    2019, 28(6): 130-137.  DOI: 10.1016/j.jechem.2018.09.005
    摘要 ( 40 )  
    Flower-like hierarchical three-dimensional NiFe layered double hydroxides hollow microspheres (3D NiFeLDH HMS), as one kind of novel non-noble metal electrocatalysts, have been fabricated in a templatefree route for water oxidation. Both of the concentration of ammonium fluoride and the reaction time are adjusted to obtain a series of NiFe-LDH microspheres, with different internal structures from massive to hollow generated during the hydrothermal treatment, which improve the electrocatalytic activity of the NiFe-LDH catalysts towards the evolution reaction of oxygen. The optimized NiFe-LDH-0.4M HMS show the excellent OER performance in alkaline electrolyte with η=290 mV@10 mA cm-2, and a Tafel slope of 51 mV dec-1, which outperforms the benchmark RuO2 catalyst. The possible reason is attributed to the more exposure of active sites, and fast ion transport resulting from the hierarchical hollow structure.
    Theoretical insights into interfacial and electronic structures of NiOx/SrTiO3 photocatalyst for overall water splitting
    Miaomiao Wang, Shenmin Li, Yang Lv, Xin Zhou
    2019, 28(6): 138-148.  DOI: 10.1016/j.jechem.2018.09.007
    摘要 ( 42 )  
    SrTiO3 is a promising candidate photocatalyst for overall water splitting. Loading suitable cocatalysts, such as NiOx, the mixture of Ni and NiO, remarkably improve the photocatalytic activity. However, spatial locations and functions of components in NiOx/SrTiO3 are under debate. Here, using first-principles density functional theory (DFT) calculations, we investigate the initial growth of Nin (n=1-4) and (NiO)n (n=1, 2 and 4) clusters on stoichiometric (100) surfaces of SrTiO3, and explore interfacial and electronic structures of composite photocatalysts. It is found that Nin clusters are easier to undergo aggregation on SrOtermination than on TiO2-termination. The adsorption of Nin cluster on (100) surfaces elevates the Fermi level towards the conduction band, which may benefit the occurrence of hydrogen evolution reaction. The structural similarity between (NiO)n cluster and surface has an essential effect on the most stable adsorption configuration. For (NiO)n/SrTiO3 systems, the occupied states of (NiO)n cluster well overlap with those of (100) surfaces in the valence band maximum, which is in favor of the separation of photogenerated electrons and holes to SrTiO3 support and (NiO)n cluster, respectively. The detailed DFT analysis provides important insights into the growth of NiOx on surfaces of SrTiO3 and presents an explanation on the different models of NiOx/SrTiO3 photocatalyst proposed by experimental groups. Our calculations build a basis for further investigations on the mechanism of photocatalytic water-splitting reaction in NiOx/SrTiO3 composite system.
    A one-pot method for controlled synthesis and selective etching of organic-inorganic hybrid perovskite crystals
    Yu Hou, Mengjiong Chen, Hongwei Qiao, Huagui Yang
    2019, 28(6): 149-154.  DOI: 10.1016/j.jechem.2018.08.013
    摘要 ( 39 )  
    Organometal halide perovskites have recently emerged with a huge potential for photovoltaic applications. Moreover, preparation of high-quality perovskite crystals with controlled morphology is of great significance for the fundamental studies such as optical and electrical properties, as well as the applications. Here, we report a one-pot solvothermal process to synthesize sheet-shaped CH3NH3PbBr3 single crystals with the lateral size of 100 μm and the thickness of 3-8 μm. Furthermore, a controlled etching behavior on the crystalline surface was demonstrated, which could be the irregular collapse of the crystalline surface caused by the local accumulation of methylammonium cations. Using this technique, CH3NH3PbBr3 single crystal sheets could be used in the various optoelectronic devices, such as nanolaser, optical sensors, photodetectors and field effect transistors.
    Strain engineering the D-band center for Janus MoSSe edge: Nitrogen fixation
    Xi Tang, Zengxi Wei, Quanhui Liu, Jianmin Ma
    2019, 28(6): 155-159.  DOI: 10.1016/j.jechem.2018.09.008
    摘要 ( 44 )  
    Nitrogen fixation is one of the most important and challenging process in production of ammonia at ambient temperature. We have first performed density function theory to propose the edge of Janus MoSSe (EJM) monolayer as a potential catalyst for nitrogen reduction reaction. Our results show that the superficial D-band centers play an important role in nitrogen fixation. The strain effects greatly alter the D-band center, and further change the interaction between the adsorbates and the surface of catalysts. Our findings provide a new thought into designing transition-metal chalcogenide catalysts for nitrogen fixation.
    Electrospun CoSe@N-doped carbon nanofibers with highly capacitive Li storage
    Jiandong Liu, Jiaojiao Liang, Caiyun Wang, Jianmin Ma
    2019, 28(6): 160-166.  DOI: 10.1016/j.jechem.2018.09.006
    摘要 ( 35 )  
    One-dimensional nano-structured materials have attracted attention due to its unique properties afforded such as the across-linked structures and large aspect ratios. In this work, one-dimensional CoSe@Ndoped carbon nanofibers (CoSe@NC NFs) are successfully by combining the techniques of electrospinning and annealing. Selenium powder are directly dispersed in the polyacrylonitrile/N,N-Dimethylformamide (DMF) solution containing cobalt salt to form the product. The performance of these materials was investigated in Li-ion batteries after the annealing at different temperatures. The CoSe@NC nanofibers annealed at 550℃ (CoSe@NC-550) and displayed excellent storage properties, affording a high capacity of 796 mAh·g-1 at a current density of 1 A·g-1 for 100 cycles. Moreover, it is confirmed that the pseudocapacitive contribution of CoSe@NC-550 is up to 72.8% at the scan rate of 1 mV/s through the cyclic voltammetry analysis.