纳米级LiNi0.05Mn1.95O4正极材料制备及电化学性能研究
Study on preparation and electrochemical properties of nano-sized LiNi0.05Mn1.95O4 cathode materials
钱志慧 1朱琴 1马姣 1郭昱娇 2向明武 1郭俊明1
作者信息
- 1. 云南民族大学化学与环境学院,云南省高校绿色化学材料重点实验室,云南昆明 650500
- 2. 云南民族大学化学与环境学院,云南省高校绿色化学材料重点实验室,云南昆明 650500;昆明理工大学环境科学与工程学院,云南昆明 650093
- 折叠
摘要
为有效抑制尖晶石锰酸锂的Jahn-Teller效应,改善其在高倍率充放电循环中容量衰减快的问题,采取熔盐燃烧法和不同焙烧温度成功制得LiNi0.05Mn1.95O4样品.实验结果表明,Ni掺杂和不同的焙烧温度没有改变LiMn2O4的晶体结构,随焙烧温度升高,结晶性增加,颗粒尺寸增大,逐渐由纳米级变为亚微米级.在优化焙烧温度650℃下制备的样品电化学性能最优,5C下初始放电比容量及500次循环后容量保持率分别为100.8 mA·h/g和80.0%,更高倍率(10C)下500次循环容量仅衰减7.5%.动力学性能测试结果表明,其具有较大锂离子扩散系数(3.26×10-16 cm2/s)和较小表观活化能(25.67 kJ/mol).Ni掺杂和不同的焙烧温度抑制了LiMn2O4材料的Jahn-Teller效应,提高了材料的倍率性能和循环寿命.
Abstract
To effectively suppress Jahn-Teller effect of spinel lithium manganate and improve the problem of rapid capacity decay during high-rate charge discharge cycles,the LiNi0.05Mn1.95O4 samples were successfully prepared by using a molten salt combustion method and different calcination temperatures.The experiment results demonstrated that the crystal struc-ture of LiMn2O4 did not change under Ni-doping and different calcination temperatures.With the rise of calcination tempera-ture,the crystallinity and particle size of the samples were increased continuously.Besides,the particle sizes were gradually increased from nanoscales to submicron scales.The optimal calcination temperature of 650℃ delivered excellent electro-chemical performance.The initial discharge specific capacity at 5C and the capacity retention rate after 500 cycles were 100.8 mA·h/g and 80.0％,respectively.At a higher rate of 10C,the capacity of 500 cycles only attenuated by 7.5％.The dy-namic performance test results indicated that it had a large lithium-ion diffusion coefficient of 3.26×10-16 cm2/s and a smaller apparent activation energy of 25.67 kJ/mol.Ni doping and different calcination temperatures inhibited the Jahn-Teller effect of LiMn2O4 materials,thereby promoted the rate performance and cycle life of LiMn2O4 materials.
关键词
尖晶石型LiMn2O4/Ni掺杂/熔盐燃烧法/Jahn-Teller效应/焙烧温度Key words
spinel LiMn2O4/Ni-doping/molten-salt combustion method/Jahn-Teller effect/calcination temperature引用本文复制引用
基金项目
国家自然科学基金(51972282)
国家自然科学基金(U1602273)
出版年
2024
NETL
NSTL
万方数据