碳包覆介孔四氧化三铁纳米阵列:高性能Ni/Fe水相电池阴极材料

阴极材料的开发对于可充电水相电池的发展具有重要意义.本文通过自牺牲模板法和碳包覆法相结合制备了碳包覆介孔Fe₃O₄纳米阵列阴极材料(Fe₃O₄@C MNAs).得益于包覆碳层、介孔结构和纳米阵列结构的优异特性, Fe₃O₄@C MNAs电极表现出良好的倍率性能和优秀的循环稳定性.在组装的Ni/Fe电池器件中, Fe₃O₄@C MNAs表现出较高的能量密度及功率密度(在能量密度为213.3 W h kg^-1时功率密度为0.658 kW kg^-1和在功率密度为20.7 kW kg^-1时能量密度为113.9 W h kg^-1)和出色的循环稳定性(约5000次循环后保持81.7%).

Mesoporous Fe3O4@C nanoarrays as high-performance anode for rechargeable Ni/Fe battery

Rechargeable aqueous batteries with high power density and energy density are highly desired for electrochemical energy storage.Despite the recent reports of various cathode materials with ultrahigh pseudocapacitance exceeding3000 F g^-1(or 800 mA h g^-1),the development of anode materials is relatively insufficient,which limits the whole performance of the devices far from practical applications.Herein,we report the preparation of mesoporous Fe₃O₄@C nanoarrays as high-performance anode for rechargeable Ni/Fe battery by a self-generated sacrificial template method.Zn O/Fe₃O₄composite was first synthesized by a co-deposition process,and Zn O was subsequently removed by alkali etching to construct the mesoporous structure.A thin carbon film was introduced onto the surface of the electrode by the carbonization of glucose to increase the structural stability of the electrode.The unique mesoporous nanoarray architecture endows the electrode with larger specific surface area,faster charge/mass transport and higher utilization of Fe₃O₄,which shows an ultrahigh specific capacity (292.4 mA h g^-1at a current density of 5 mA cm^-2) and superior stability in aqueous electrolyte (capacitance retention of 90.8%after 5000cycles).After assembled with hierarchical mesoporous Ni O nanoarray as a cathode,an optimized rechargeable Ni/Fe battery with double mesoporous nanoarray electrodes was fabricated,which provided high energy/power densities(213.3 W h kg^-1at 0.658 kW kg^-1and 20.7 kW kg^-1at113.9 W h kg^-1,based on the total mass of the active materials)in the potential window of 1.5 V with excellent cyclability(81.7%retention after 5000 charge/discharge cycles).