5V锂离子电池正极材料LiNi0.5Mn1.5O4的合成与Li+ 在材料中的扩散性能

摘要

5 V cathode material LiNi05M1.5O4 was synthesized via an oxalate co-precipitation method, and the relationship between the structure, morphology and the electrochemical performance of the material was investigated. The results show that the sample synthesized at 900 C has the best electrochemical perfornance. Its initial discharge capacity reaches 133.0 mA · h/g, and after cycled for 30 times, still maintains at 132. 2 mA · h/g( capacity retention 99. 4％ ). The chemical diffusion coefficient of Li + ion in LiNio. 5M1.5O4 cathode material was measured by potentiostatic intermittent titration technique(PITY) and electrochemical impedance spectroscopy(ELS). The chemical diffusion coefficient of Li + ion ranges in 10-10-10-11 cm2/s.%采用草酸盐共沉淀法合成了5 V正极材料LiNi0.5Mn1.5O4,研究了不同温度下合成材料的结构形貌与电化学性能之间的关系.结果表明,在900 ℃下合成样品的电化学性能最好,首次放电容量达到133.0 mA·h/g,经30周循环后,容量仍然保持在132.2 mA*h/g,容量保持率高达99.4%.采用恒电位间歇滴定法(PITT)和电化学阻抗谱法(EIS)测定了锂离子在LiNi0.5Mn1.5O4材料中的扩散系数.结果表明,在LiNi0.5Mn1.5O4材料放电过程中,在不同的电位下,锂离子扩散系数在10-10～10-11 cm2/s范围内变化.