Effects of gradient concentration on the microstructure and electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode materials  

作　　者：Wenming Li Weijian Tang Maoqin Qiu Qiuge Zhang Muhammad Irfan Zeheng Yang Weixin Zhang 

机构地区：[1]School of Chemistry and Chemical Engineering,Hefei University of Technology,Hefei 230009,China

出　　处：《Frontiers of Chemical Science and Engineering》2020年第6期988-996,共9页化学科学与工程前沿（英文版）

基　　金：the financial support of the National Natural Science Foundation of China(Grant Nos.91834301,91534102 and 21271058);Science and Technology Project of Anhui Province(Nos.201903a05020021 and 17030901067).

摘　　要：Nickel(Ni)-rich layered materials have attracted considerable interests as promising cathode materials for lithium ion batteries(LIBs)owing to their higher capacities and lower cost.Nevertheless,Mn-rich cathode materials usually suffer from poor cyclability caused by the unavoidable side-reactions between Ni^4+ions on the surface a nd electrolytes.The design of gradient concentration(GC)particles with Ni-rich inside and Mn-rich outside is proved to be an efficient way to address the issue.Herein,a series of LiNi0.6Co0.2Mn0.2O2(LNCM 622)materials with different GCs(the atomic ratio of Ni/Mn decreasing from the core to the outer layer)have been successfully synthesized via rationally designed co-precipitation process.Experimental results demonstrate that the GC of LNCM 622 materials plays an important role in their microstructure and electrochemical properties.The as-prepared GC3.5 cathode material with optimal GC can provide a shorter pathway for lithium-ion diffusion and stabilize the near-surface region,and finally achieve excellent electrochemical performances,delivering a discharge capacity over 176 mAh·g^-1 at 0.2 C rate and exhibiting capacity retention up to 94%after 100 cycles at 1 C.T h e rationally-designed co-precipitation process for fabricating the Ni-rich layered cathode materials with gradient composition lays a solid foundation for the preparation of high-performance cathode materials for LIBs.

关 键 词：gradient concentration Ni-rich LiNi0.6Co0.2Mn0.2O2 electrochemical performance lithiumion battery 

分 类 号：O646[理学—物理化学]