Ni-Fe共掺LiMn_(2)O_(4)正极材料的合成及电化学性能研究  

Synthesis of Ni-Fe co-doped LiMn_(2)O_(4) cathode material and its electrochemical performance

作　　者：王紫林 刘红雷 郭昱娇 吉颖 向明武 刘晓芳[1] 郭俊明[1] WANG Zi-lin;LIU Hong-lei;GUO Yu-jiao;JI Ying;XIANG Ming-wu;LIU Xiao-fang;GUO Jun-ming(Yunnan Provincial Higher Educational Key Laboratory of Green-chemical Materials,Yunnan Minzu University,Kunming 650500,China;Ecology and Environment Monitoring Station,Wuhua Branch,Kunming Municipal Ecology and Environment Bureau,Kunming 650031,China)

机构地区：[1]云南民族大学云南省高校绿色化学材料重点实验室,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

出　　处：《现代化工》2023年第8期126-132,共7页Modern Chemical Industry

基　　金：国家自然科学基金(51972282)。

摘　　要：采用固相燃烧法快速合成了LiNi_(0.08)Fe_(x)Mn_(1.92-x)O_(4)(x≤0.08)正极材料,并探究了正极材料样品的结构、形貌、电化学性能及动力学性能。结果表明,Ni-Fe共掺没有改变LiMn_(2)O_(4)的立方尖晶石结构,促进了其晶体发育和{111}、{110}、{100}晶面的择优生长,部分颗粒形成了以高暴露{111}晶面为主和少量{110}、{100}晶面的截断八面体形貌。LiNi_(0.08)Fe_(0.05)Mn_(1.87)O_(4)样品在较低倍率(≤5 C)时,其倍率性能和长循环寿命得到显著提高,在25℃下,1 C的首次放电比容量为106.1 mAh/g, 1 000次循环后容量保持率为82.0%;5 C的首次放电比容量为100.1 mAh/g, 2 000次循环后容量保持率为72.8%。LiNi_(0.08)Fe_(0.05)Mn_(1.87)O_(4)材料的锂离子扩散系数和表观活化能分别为1.75×10^(-15)cm^(2)/s和26.52 kJ/mol,表明其有较好的Li+迁移动力学性能。LiNi_(0.08)Fe_(x)Mn_(1.92-x)O_(4)(x≤0.08)cathode material is rapidly synthesized via solid-state combustion method.The structure,morphology,electrochemical performance,and kinetic performance of the material samples are investigated.The results show that LiNi_(0.08)Fe_(0.05)Mn_(1.87)O_(4) cathode material has a cubic spinel structure,which promotes the crystal development of LiMn_(2)O_(4) and the preferential growth of{111},{110}and{100}crystal planes.Some particles form a truncated octahedron shape with highly exposed{111}crystal planes and a small amount of{110}and{100}crystal planes,which significantly improves the rate capability and long cycle life of the material at lower rates(≤5 C).At 25℃,the material has an 106.1 mAh·g^(-1) of 1 C initial discharge specific capacity,and a 82.0%of capacity retention rate after 1,000 cycles.At 5 C,it has a 100.1 mAh·g^(-1) of initial discharge specific capacity and a 72.8% of capacity retention rate after 2,000 cycles.The lithium ion diffusion coefficient and apparent activation energy of LiNi_(0.08)Fe_(0.05)Mn_(1.87)O_(4) material are 1.75×10^(-15) cm^(2)·s^(-1) and 26.52 kJ·mol^(-1),respectively,representing a good Li+migration kinetics.

关 键 词：LiMn_(2)O_(4) Ni-Fe共掺杂 截断八面体 固相燃烧法 JAHN-TELLER畸变 Mn溶解 正极材料 

分 类 号：TM912[电气工程—电力电子与电力传动]