双位点配位聚合物改性的无钴富锂锰基正极材料电化学性能研究  

Electrochemical properties of two-site coordination polymer modified Co-free Li-rich manganese-based cathode

作　　者：张思玉 陈敏健 马骋 张春晓 韦伟峰[1] ZHANG Siyu;CHEN Minjian;MA Cheng;ZHANG Chunxiao;WEI Weifeng(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2022年第1期83-91,共9页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(51971250)。

摘　　要：以无钴Li_(1.2)Mn_(0.53)Ni_(0.27)O_(2)材料、有机单体乙酰乙酸甲基丙烯酸乙二醇酯(Acetoacetate ethylene glycol methacrylate,AAEM)为原料,采用溶液原位聚合法在无钴Li_(1.2)Mn_(0.53)Ni_(0.27)O_(2)材料表面形成有机物包覆层,得到一种高循环稳定性和界面稳定性的层状正极材料。借助透射电子显微镜、X射线光电子能谱、电化学阻抗谱等测试手段,研究AAEM对富锂锰基层状正极材料的影响。结果表明,与原始材料相比,经过AAEM改性的Li_(1.2)Mn_(0.53)Ni_(0.27)O_(2)材料在2-4.7 V的电压区间,以1C倍率经300圈循环后,容量保持率可达82%,高于原始材料经300圈循环后的67%。因此借助双位点螯合聚合物包覆层上的配位基团能够与过渡金属离子络合,提高电极/电解质之间的界面稳定性,使正极材料的循环稳定性增加,提高材料的电化学性能。Using cobalt-free Li_(1.2)Mn_(0.53)Ni_(0.27)O_(2)(LMNO) cathode material and Acetoacetate ethylene glycol methacrylate(AAEM) as raw materials,in-situ solution polymerization of AAEM was used to form an organic coating layer on the surface of cobalt-free LMNO cathodematerial to improve its cycling stability and interfacial stability.The influence of AAEM on LMNO layered cathode materials were studied using Transmission electron microscope (TEM),X-ray photoelectron spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS),etc.Theresults show that the capacity retention rate of the modified sample is as high as 82%after 300 cyclesat 1C cycle within the voltage range of2-4.7 V,which is much higher than that of the pristine sample (67%after 300 cycles).The refore,the coordination group on the double-site chelating polymer layer can coordinate with the Transition Metal (TM) ion,which enhances the electrode/electrolyte interfacial stability,increases the cycle stability of cathode materials,and improves the electrochemical performance of the material.

关 键 词：无钴富锂锰基层状正极材料 有机配位聚合物 表面包覆 电极/电解质界面 循环稳定性 

分 类 号：TM912[电气工程—电力电子与电力传动]