The F-doped O3-type NaNi1/3Fe1/3Mn1/3O2-xFx （x = 0, 0.005, 0.01,002 and noted as NFM-F0, NFM-F0.005, NFM-F0.01, NFM-F0.02, respectively, united as NFM-Fs） cathode materials were investigated systematically. The rate...The F-doped O3-type NaNi1/3Fe1/3Mn1/3O2-xFx （x = 0, 0.005, 0.01,002 and noted as NFM-F0, NFM-F0.005, NFM-F0.01, NFM-F0.02, respectively, united as NFM-Fs） cathode materials were investigated systematically. The rate performance and capacity retention of the O3-type cathode materials are significantly improved as a function of specific F-doping levels. Optimum performance is achieved in the NFM-F0.01 material having a capacity of -110mAhg-1 at a current density of 150mAg-1 after 70 cycles. The results indicate that the binding energy of oxygen changes as a result of F-doping, and in addition, F-doping results in changes to the stoichiometry of Mn3＋/Mn4＋, which stabilizes the O3-type layered structure, thus allowing cycling performance to be improved. However, NFM-F0.02, having a higher F-doping level, retains a high capacity retention, although a slight loss is observed. The results suggest there is an optimum F-doping level for the NFM-F system to deliver enhanced cycling performance.展开更多
基金supported by the National High-Tech R&D Program of China (2015AA034601, 2016YFB010030X, and 2016YFB0700600)the State Key Laboratory of Materials Processing and Die & Mould Technologythe Analytical and Testing Center of Huazhong University of Science Technology
文摘The F-doped O3-type NaNi1/3Fe1/3Mn1/3O2-xFx （x = 0, 0.005, 0.01,002 and noted as NFM-F0, NFM-F0.005, NFM-F0.01, NFM-F0.02, respectively, united as NFM-Fs） cathode materials were investigated systematically. The rate performance and capacity retention of the O3-type cathode materials are significantly improved as a function of specific F-doping levels. Optimum performance is achieved in the NFM-F0.01 material having a capacity of -110mAhg-1 at a current density of 150mAg-1 after 70 cycles. The results indicate that the binding energy of oxygen changes as a result of F-doping, and in addition, F-doping results in changes to the stoichiometry of Mn3＋/Mn4＋, which stabilizes the O3-type layered structure, thus allowing cycling performance to be improved. However, NFM-F0.02, having a higher F-doping level, retains a high capacity retention, although a slight loss is observed. The results suggest there is an optimum F-doping level for the NFM-F system to deliver enhanced cycling performance.
