洗涤和热处理对LiNi0.8Co0.15Al0.05O2正极材料结构和电化学充放电性能的影响

用去离子水将原始的LiNi_0.8Co_0.15Al_0.05O₂正极材料进行洗涤并分别在不同温度下处理相同的时间, 讨论了LiNi_0.8Co_0.15Al_0.05O₂正极材料结构、形貌以及电化学充放电性能的变化, 同时探讨了洗涤和热处理对材料结构、电化学充放电性能以及倍率性能影响的机理。XRD分析表明: 在洗涤和热处理之后, LiNi_0.8Co_0.15Al_0.05O₂正极材料的I₍₀₀₃₎/I₍₁₀₄₎比值以及晶胞体积均有变小; 傅里叶红外光谱分析表明: 在洗涤和热处理之后, LiNi_0.8Co_0.15Al_0.05O₂正极材料中形成了碳酸锂、镍化合物杂质及其相关变化。同时对洗涤和热处理前后LiNi_0.8Co_0.15Al_0.05O₂正极材料容量和倍率性能进行测试。容量测试结果表明: 原始样品以及处理后样品在30圈循环之后容量保持率分别为88.87%、 87.21%、85.43%和87.80%。

Effects of Washing and Heat-treatment on Structure and Electrochemical Charge/Discharge Property of LiNi0.8Co0.15Al0.05O2 Powder

The effect of washing on electrochemical properties of Ni-rich layered cathode LiNi_0.8Co_0.15Al_0.05O₂ powder is widely known, but few literatures have reported thoroughly. Primitive LiNi_0.8Co_0.15Al_0.05O₂ powders processed by deionized water and heat-treatment at different temperatures in a paralleling time was explored for the first time. Significant changes of structure, morphology and electrochemical charge/discharge property of the LiNi_0.8Co_0.15Al_0.05O₂ cathode were detected comprehensively. Mechanism of washing and heat-treatment on the structure and electrochemical charge/discharge property and the rate performance were studied. XRD patterns show the I₍₀₀₃₎/I₍₁₀₄₎ value of LiNi_0.8Co_0.15Al_0.05O₂ powders decreases and the volume turns smaller after being washed and heat-treated. FT-IR spectra confirm the existence of lithium carbonate, and nickel compounds and their relative changes in the LiNi_0.8Co_0.15Al_0.05O₂ powders. The specific capacity and rate performance of the LiNi_0.8Co_0.15Al_0.05O₂ powders were carried out before and after washing and heat-treatment. The capacities of primitive sample and treated samples remain 88.87%, 87.21%, 85.43% and 87.80% after 30 cycles, respectively.