锂离子电池正极材料LiNixMn2-xO4的制备和电化学性能研究

采用固相反应和湿化学两种方法合成了材料LiNixMn2-xO4含Ni量影响材料在4．7V高电压区间的容量，用固相反应法制备的LiNi0.5Mn1.5O4中含有杂相物质，首次放电容量可以达到118mAh／g，其中高电压区的容量为100mAh／g，循环50次的容量保持率为97％。用湿化学法可以得到纯相的LiNi0.5Mn1.5O4，首次放电容量为140mAh／g，其中高电压区的容量为125mAh／g，循环50次后，容量仍能达到133mAh／g，容量保持率为95％。XPS检测结果表明，湿化学法制备的LiNi0.5Mn1.5O4中Mn为＋4价，Ni为＋2价。

Synthesis and Electrochemical Performance of LiNixMn2-xO4 Spinel as Cathode Material for Lithium Ion Batteries

Solid-state method and wet method were employed to synthesize spinel compounds LiNixMn2-xO4.The experimental results indicate that the capacity of high voltage at 4.7 V increase with the increase of amount of Ni. There are impurities in LiNixMn2-xO4 which were made by solid-state method. The sample LiNi0.5Mn1.5O4 had a capacity of 121 mAh/g at first cycle, in which 100 mAh/g was at high voltage range. Its cycle retention rate after 50 cycles was over 92%. The LiNi0.5Mn1.5O4 synthesized by wet method show a single spinel phase without impurity phase. It deliver a discharge capacity of 140 mAh/g in the first cycle, in which 125 mAh/g was at high voltage range. Its cycle retention rate after 50 cycles was over 96%. The XPS experiment results indicate that the oxidation states of Ni and Mn in LiNi0.5Mn1.5O4 made by wet method are +2 and +4 respectively.