Structural evolution of mesoporous graphene/LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2) composite cathode for Li-ion battery  

作　　者：Wen-Jie Liu Xian-Zhong Sun Xiong Zhang Chen Li Kai Wang Wen Wen Yan-Wei Ma 

机构地区：[1]Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100190,China [3]Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201204,China

出　　处：《Rare Metals》2021年第3期521-528,共8页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51822706 and51777200);the Beijing Municipal and Technology Commission(No.Z181100000118006)。

摘　　要：Layered LiMO_(2)(M=Ni,Co,and Mn) is a type of promising cathode materials for high energy density and high work voltage lithium-ion batteries.However,the poor rate performance and low power density hinder its further applications.The capacity fade is related to the structural transformation in the layered LiMO_(2).In this work,the structural changes of bi-material cathode composed of mesoporous graphene and layered LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM) were studied via in situ X-ray diffraction(XRD).During different C-rate charge-discharge test at the voltage range of 2.5-4.1 V,the composite cathode of NCM-graphene(NCM-G) reveals better rate performances than pure NCM cathode.The NCM-G composite electrode displays a higher rate capability of 76.7 mAh·g^(-1) at 5 C rate,compared to the pure NCM cathode of 69.8 mAh·g^(-1)discharge capacity.The in situ XRD results indicate that a reversible phase transition from hexagonal H1 to hexagonal H2 occurs in layered NCM material during 1 C chargedischarge process.With the current increasing to 2 C/5 C,the structure of layered NCM material for both electrodes reveals few changes during charge and discharge processes,which indicates the less utilization of NCM component at high C-rates.Hence,the improved rate performance for bi-material electrode is attributed to the highly conductive mesoporous graphene and the synergistic effect of mesoporous graphene and NCM material.

关 键 词：LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM) Mesoporous graphene BI-MATERIAL In situ X-ray diffraction(XRD) Structural evolution 

分 类 号：TM912[电气工程—电力电子与电力传动] TB332[一般工业技术—材料科学与工程]