单晶多面体LiAl_(0.08)Ni_(0.03)Mn_(1.89)O_(4)正极材料合成及电化学性能  

Preparation and Electrochemical Performance of Single Crystal Polyhedron LiAl_(0.08)Ni_(0.03)Mn_(1.89)O_(4)Cathode Material

作　　者：郭昱娇 卢瑶 宁平[1] 郭俊明 Guo Yujiao;Lu Yao;Ning Ping;Guo Junming(Faculty of Environmental Science and Engineering,Kunming University of Science and Technology,Kunming 650500,China;Eco-environment Monitoring Station of Wuhua Branch,Kunming Eco-environment Bureau,Kunming 650031,China;School of Chemistry and Environment,Yunnan Minzu University,Kunming 650500,China)

机构地区：[1]昆明理工大学环境科学与工程学院,云南昆明650500 [2]昆明市生态环境局五华分局生态环境监测站,云南昆明650031 [3]云南民族大学化学与环境学院,云南昆明650500

出　　处：《稀有金属材料与工程》2021年第12期4525-4533,共9页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51972282,U1602273)。

摘　　要：采用固相燃烧法快速合成了单晶多面体LiAl_(0.08)Ni_(0.03)Mn_(1.89)O_(4)(LANMO)锂离子电池正极材料,其单晶颗粒暴露面包含{111}、{110}和{100}晶面。结果表明,LANMO材料为单相尖晶石型结构,属于Fd3m空间群,结晶性好,颗粒尺寸200~300 nm。在1和5 C倍率下LANMO的初始放电比容量分别为110.6和96 mAh·g^(-1),循环1000次后容量保持率都达到70%以上;在高温(55℃)1 C条件下,LANMO材料具有114.2 mAh·g^(-1)初始放电比容量,表现出优良的电化学性能。动力学性能测试表明,LANMO样品有较高的Li^(+)离子扩散系数1.58×10^-(11)cm^(2)·s^(-1)和较低的表观活化能23.89kJ·mol^(-1)。Al-Ni协同改性提高了单晶多面体尖晶石型LiMn_(2)O_(4)材料的晶体结构稳定性,有效抑制了Jahn-Teller效应,降低了Mn的溶解,增加了Li^(+)扩散通道,从而增大了Li^(+)扩散速率和电极可逆性,提升了其倍率性能和循环寿命。The cathode material of single-crystal polyhedral LiAl_(0.08)Ni_(0.03)Mn_(1.89)O_(4)(LANMO)was rapidly synthesized by a solid-phase combustion method.The exposed surfaces of the single-crystal particles include{111},{110}and{100}crystal faces.The results show that LANMO material is a single-phase spinel structure,belonging to the space group Fd3m and exhibits good crystallinity,the particle size is between 200 nm to 300 nm.The initial discharge specific capacity of LANMO is 110.6 and 96 mAh·g^(-1)at 1 C and 5 C,respectively,and the capacity retention rate reaches more than 70%after 1000 cycles.Under the elevated temperature(55℃)and the discharge rate of 1 C condition,the LANMO material also has an initial discharge specific capacity of 114.2 mAh·g^(-1),showing excellent electrochemical performance.The kinetic performance test shows that the LANMO sample has a higher Li^(+)ion diffusion coefficient of 1.58×10^-(11)cm^(2)·s^(-1)and a lower apparent activation energy of 23.89 kJ·mol^(-1).The Al-Ni synergistic modification improves the crystal structure stability of single crystal polyhedral spinel LiMn_(2)O_(4)material,inhibits the Jahn-Teller effect effectively,reduces Mn dissolution,increases Li^(+)diffusion channels,Li^(+)diffusion rate and electrode reversibility,as well as improves the rate performance and cycle life.

关 键 词：LiMn O Ni-Al共掺 单晶多面体 固相燃烧法 正极材料 JAHN-TELLER效应 

分 类 号：TM912[电气工程—电力电子与电力传动]