A study of the structure-activity relationship of the electrochemical performance and Li/Ni mixing of lithium-rich materials by neutron diffraction

作者：Zhao, Enyue; Hu, Zhongbo; Xie, Lei; Chen, Xiping; Xiao, Xiaoling^*; Liu, Xiangfeng

来源：RSC Advances, 2015, 5(39): 31238-31244.

DOI：10.1039/c5ra02380g

• LI-ION BATTERIES
• POSITIVE-ELECTRODE MATERIALS
• HIGH-RATE CAPABILITY
• CATHODE MATERIAL
• SURFACE MODIFICATION
• ANOMALOUS CAPACITY
• CYCLING STABILITY
• LAYERED OXIDES
• OXYGEN LOSS
• LIMO2 M

0.3Li(2)MnO(3)center dot 0.7LiNi(0.5-x)Mn(0.5-x)M(2x)O(2) (M = Mg or Al, x = 0-0.08) samples have been synthesized by a combination of co-precipitation (CP) and solid-state reaction. Electrochemical measurements show that not only can the charge-discharge capacity of lithium-rich materials be enhanced, but more importantly, the rate capacity can be greatly improved by doping with magnesium and aluminum. At a current density of 400 mA g(-1), the 0.3Li(2)MnO(3)center dot 0.7LiNi(0.46)Mn(0.46)Mg(0.08)O(2) and 0.3Li(2)MnO(3)center dot 0.7LiNi(0.49)Mn(0.49)Al(0.02)O(2) electrodes deliver discharge capacities of 135 mA h g(-1) and 127 mA h g(-1), respectively, while the pristine electrode delivers a discharge capacity of only 10 mA h g(-1). Through studying the structure of lithium-rich materials, we find that the Li/Ni mixing of lithium-rich materials is reduced by doping with magnesium and aluminum, in turn, the performance of doped lithium-rich materials is improved greatly. Furthermore, compared with Al-doped lithium-rich materials, the Li/Ni mixing of Mg-doped materials is further reduced. So the performance improvement of Mg-doped lithium-rich materials is more obvious than that of Al-doped materials.

• 出版日期2015
• 单位中国科学院大学; 中国工程物理研究院核物理与化学研究所; 中国工程物理研究院