铝掺杂对富锂正极材料结构及电化学性能影响

Effects of aluminum doping on structure and electrochemical performance of lithium rich cathode materials

采用共沉淀-高温烧结法制备富锂正极材料Li[Li0.20Ni0.20-x/2Mn0.60-x/2]AlxO2(x=0,0.03,0.06,0.09),考察掺铝量对材料结构及电化学性能的影响。采用X射线衍射(XRD)、透射电镜(TEM)和能谱(EDS)研究材料晶体结构和元素分布,交流阻抗及电池充放电测试电化学性能。结果表明,铝首先选择固溶在Li2Mn O3中,然后固溶在Li MO2中;掺杂铝导致材料常温下容量显著降低,高温下得到很高的可逆容量;掺杂铝2.5%(质量分数)可以极大提高材料容量保持率,并显著降低首次不可逆容量。

Lithium-rich materials Li[Li0.20Ni0.20-x/2Mn0.60-x/2]AlxO2（x=0,0.03,0.06,0.09） were prepared by co-precipitation method. Effects of Aluminum doping on the structure and electrochemical performance were studied. The structure, distribution of aluminum on particle and electrochemical performance were characterized by XRD, TEM, EDS, EIS and galvanostaUc cycling. The results show that aluminum is substituted firstly in Li2MnO3 then in LiMO2. The discharge capacity of Li-rich material with doping aluminum dramatically decreases at 25 ℃, but high capacity is obtained at 45℃. With doping 2.5% of aluminum, the capacity retention is significantly improved, and the initial irreversible capacity can be significantly decreased.