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
We reported a facile and robust one-pot wet chemistry strategy to achieve the growth of uniform three dimensional（3D） MoSe_2 ultrathin nanostructures on graphene nanosheets to form high quality MoSe_2/rGO hybrid nan...We reported a facile and robust one-pot wet chemistry strategy to achieve the growth of uniform three dimensional（3D） MoSe_2 ultrathin nanostructures on graphene nanosheets to form high quality MoSe_2/rGO hybrid nanostructures.Owing to the graphene as a support,it can significantly prevent the aggregation of MoSe_2 and the distribution of MoSe_2 on graphene was highly uniform.Importantly,due to the unique structures,the as-harvested MoSe_2/rGO hybrid exhibited excellent electrochemical performance as anode materials for sodium-ion battery（SIB）.When evaluated in a half cell system,the MoSe_2/rGO hybrid nanostructures could deliver a capacity of 200.2 mA h g^（-1） at8 A g^（-1） and maintain a capacity of 230.1 mA h g^（-1） over 100 cycles at 5 A g^（-1）.When coupled with Na_3V_2（PO_4）_3 cathode in a full cell system,the material could deliver a discharge capacity of 363.1 mA h g^（-1） at the current density of 0.5 A g^（-1）.Moreover,a discharge capacity of 56.4 mA h g^（-1） could be achieved even at a high current density of 10 A g^（-1）,which clearly suggested the high power capability of MoSe_2/rGO hybrid nanostructures for sodium ion energy storage.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.
基金supported by the start-up funding from Xi'an Jiaotong University,the Fundamental Research Funds for the Central Universities(2015qngzl2)the China National Funds for Excellent Young Scientists(21522106)the National Natural Science Foundation of China(21371140)
文摘We reported a facile and robust one-pot wet chemistry strategy to achieve the growth of uniform three dimensional（3D） MoSe_2 ultrathin nanostructures on graphene nanosheets to form high quality MoSe_2/rGO hybrid nanostructures.Owing to the graphene as a support,it can significantly prevent the aggregation of MoSe_2 and the distribution of MoSe_2 on graphene was highly uniform.Importantly,due to the unique structures,the as-harvested MoSe_2/rGO hybrid exhibited excellent electrochemical performance as anode materials for sodium-ion battery（SIB）.When evaluated in a half cell system,the MoSe_2/rGO hybrid nanostructures could deliver a capacity of 200.2 mA h g^（-1） at8 A g^（-1） and maintain a capacity of 230.1 mA h g^（-1） over 100 cycles at 5 A g^（-1）.When coupled with Na_3V_2（PO_4）_3 cathode in a full cell system,the material could deliver a discharge capacity of 363.1 mA h g^（-1） at the current density of 0.5 A g^（-1）.Moreover,a discharge capacity of 56.4 mA h g^（-1） could be achieved even at a high current density of 10 A g^（-1）,which clearly suggested the high power capability of MoSe_2/rGO hybrid nanostructures for sodium ion energy storage.
