Stable 4.5 V LiCoO_(2)cathode material enabled by surface manganese oxides nanoshell  

作　　者：Jun Wang Si-Dong Zhang Si-Jie Guo Si-Qi Lu Yan-Song Xu Jin-Yang Li An-Min Cao Li-Jun Wan 

机构地区：[1]CAS Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences(ICCAS),Beijing 100190,China [2]University of Chinese Academy of Sciences(UCAS),Beijing 100049,China

出　　处：《Nano Research》2023年第2期2480-2485,共6页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.22025507 and 21931012);the Key Research Program of Frontier Sciences,CAS(ZDBS-LY-SLH020);Beijing National Laboratory for Molecular Sciences(BNLMSCXXM-202010).

摘　　要：Charging the LiCoO_(2)(LCO)cathode to a higher voltage,for example 4.5 V compared to the commonly used 4.2 V,is now intensively pursued so as to achieve a higher specific capacity.However,it suffers severe surface structural degradation and detrimental interfacial side reactions between cathode and electrolyte,which lead to the fast capacity fading during long-term cycling.Here,a surface coating strategy was developed for the protection of 4.5 V LCO by constructing a manganese oxides(MOs)nanoshell around LCO particles,which was achieved through a solution-based coating process with success in controlling the growth kinetics of the coating species.We found that the introduction of the MOs nanoshell is highly effective in alleviating the organic electrolyte decomposition at the cathode surface,thus ensuring a much more stable LiF-rich cathode-electrolyte interface and an obvious lower interfacial resistance during electrochemical cycling.Meanwhile,this protection layer can effectively improve the structural stability of the cathode by hindering the cracks formation and structural degradation of LCO particles.Therefore,the MOs modified LCO exhibited excellent rate performance and a high discharge capacity retention of 81.5%after 100 cycles at 1 C compared with the untreated LCO(55.2%),as well as the improved thermal stability and cyclability at the elevated temperature.It is expected that this discovery and fundamental understanding of the surface chemistry regulation strategy provide promising insights into improving the reversibility and stability of LCO cathode at the cut-off voltage of 4.5 V.

关 键 词：lithium-ion battery 4.5 V LiCoO_(2) manganese oxides surface coating interfacial stability regulation 

分 类 号：O61[理学—无机化学]