Ni-Mn共掺杂高电压钴酸锂锂离子电池正极材料

Ni,Mn-Codoped High-Voltage LiCoO_2 Cathode Material for Lithium Ion Batteries

以金属硫酸盐为原料,Na OH和NH3·H2O为沉淀剂,用共沉淀法合成了Co0.9Ni0.05Mn0.05（OH）前驱体,再进行配锂并通过高温固相法合成了Ni-Mn共掺杂高电压钴酸锂锂离子电池正极材料Li（Co0.9Ni0.05Mn0.05）O2。用X射线衍射（XRD）、扫描电镜（SEM）、循环伏安（C-V）、交流阻抗（EIS）和充放电测试研究样品的晶体结构、形貌和电化学性能。结果表明Ni-Mn共掺杂正极材料Li（Co0.9Ni0.05Mn0.05）O2有优秀的电化学性能：在3.0～4.4 V和3.0～4.5 V区间,0.5C倍率下首次放电比容量分别为162.5 m Ah·g^-1和185 m Ah·g^-1,循环100次后容量保持率分别为94.4%和93.7%。

The precursor Co0.9Ni0.05Mn0.05（OH）2of the high-voltage cathode material for lithium ion batteries was synthesized by hydroxide co-precipitation method using the transition metal sulphate as the raw material,NaOH and NH3·H2O as the precipitate agents.Then the corresponding Li（Co0.9Ni0.05Mn0.05）O2was obtained when mixing the precursor with Li2CO3 by high solid method.Crystal structure,morphology and electrochemical performance of the sample were investigated by XRD,SEM,Cyclic voltammetry（C-V） method,electrochemical impedance spectroscopy（EIS） test and charge-discharge test.Mixed doping Ni-Mn material Li（Co0.9Ni0.05Mn0.05）O2shows better electrochemical performance compared to LiCoO2 as confirmed by the results of C-V,XRD and EIS.When the co-doped product Li（Co0.9Ni0.05Mn0.05）O2was charged to 4.4 and 4.5 V,the initial discharge capacity is 162.5 m Ah·g^-1 and 185 m Ah·g^-1 at 0.5C rate,respectively.After cycling for 100 times,the retention of discharge capacity was94.4% and 93.7%,respectively.