尖晶石LiCoxMn2-xO4材料电化学性能研究

为了提高LiMn2O4材料的性能,采用分步加热高温固相合法,合成了尖晶石型LiCoxMn2-xO4(x=0、0.04、0.08、0.1、0.12、0.16)材料,并在562 247方形实体电池LiCoxMn2-xO4/1M LiPF6-EC DEC EMC/MCMB体系中研究Co掺杂量对材料性能的影响.通过X射线衍射仪对LiCoxMn2-xO4材料结构进行了研究,发现随着Co掺杂量的增加,LiCoxMn2-xO4材料的晶胞参数不断变小,结构稳定性增加,循环性能得到提高,但材料的起始放电比容量不断减小,Co掺杂量为0.08～0.1时,材料的起始比容量较高,循环性能也均得到较大的提高.经过1 000次循环,材料的放电容量保持率在85%左右.Co的掺杂也提高了材料的高温性能及大电流工作能力,4倍率充放电时,放电容量为1倍率时的86%.

Study on the electrochemical properties of spinel LiCoxMn2-xO4

To improve the properties of spinel LiMn_2O_4,the LiCo_xMn_(2-x)O_4(x=0,0.04,0.08,0.1,0.12,0.16) was prepared by high temperature solid-phase reaction.The effect of doped-Co was studied in 562247 prismatic lithium ion battery-LiCo_xMn_(2-x)O_4/1M LiPF6-EC DEC EMC/MCMB.The structure of the cathode material was studied by means of XRD.The result shows that the lattice parameter of LiCo_xMn_(2-x)O_4 becomes smaller as X but becomes larger,the structure of the cathode material is more stable and has better cycle property,but the first discharge capacity becomes smaller.When the doped-Co is controlled between 0.08 and 0.1,the cathode material has lager specific capacity and better cycle property.After 1000 cycles,about 85% of the capacity is maintained.The properties at high temperature and high charge-recharge rates are also increased by the doped-Co.At 4C rate,the spinel LiCo0.1Mn1.9O_4 can give 86% of capacity at 1C rate.