Li_(1．02)Co_xCr_yMn_(2-x-y)O_4的固相合成及性能表征

Synthesis by Solid-state Reaction and Characterise of Li_(1.02)Co_xCr_yMn_(2-x-y)O_4

采用固相法合成锂离子正极材料尖晶石相Li1．02CoxCryMn2-x-yO4,研究元素Co、 Cr不同掺杂量对产物的结构、晶胞常数、电化学性能和电池内阻的影响．分析表明,掺杂少量的Co、Cr的LiMn2O4依然保持着尖晶石结构;晶胞常数随掺杂量的增加而减小,从而使尖晶石的比表面积增大,有利于提高电池的初始容量;并有效地抑制了充放电过程中的Jahn-Teller 效应和Mn3+的歧化反应．掺杂Co、Cr后Li1．02MnO4初始容量有所下降,且随掺杂量增加而减小,但能明显改善材料的循环性能．

The spinel Li1.02CoxCryMn2-x-yO4 as a cathode of lithium ion secondary battery was synthesized by a solid-state method. The influences of the different Cr and Co content in the LiMn2O4 on phase constitution and structure, lattice parameters and electrochemical properties were investigated. The spinel structure was kept still with inserting a small amount of Cr and Co to Li1.02Mn2O4. The Jahn-Teller distortion and the Mn^3＋ disproportionation reaction were restrained efficiently. With the substitution content of Cr and Co increased, the lattice parameters of Li1.02Mn2O4 decreased, while specific surface area was increased, and the specific capacity of the cell was improved. In addition, the initial capacity was decreased, but the cycle performance of materials was improved obviously.