In-situ construction of a thermodynamically stabilized interface on the surface of single crystalline Ni-rich cathode materials via a onestep molten-salt route  

作　　者：Huiya Yang Xiangbang Kong Jiyang Li Pengpeng Dai Jing Zeng Yang Yang Jinbao Zhao 

机构地区：[1]State Key Laboratory of Physical Chemistry of Solid Surfaces,Collaborative Innovation Centre of Chemistry for Energy Materials,State-Province Joint Engineering Laboratory of Power Source Technology for New Energy Vehicle,Engineering Research Center of Electrochemical Technology,Ministry of Education,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China

出　　处：《Nano Research》2023年第5期6771-6779,共9页纳米研究（英文版）

基　　金：the financial support of the Key Project of Science and Technology of Xiamen(No.3502Z20201013);the National Natural Science Foundation of China(Nos.21875198,21875195,and 22021001)。

摘　　要：Nickel rich LiNi_(x)Co_(y)Mn_(1−x−y)O_(2)cathode materials have been studied extensively to increase the energy density of lithium-ion batteries(LIBs)due to their advantages of high capacity and low cost.However,the anisotropic crystal expansion and contraction inside the secondary particles would cause detrimental micro-cracks and severe parasitic reactions at the electrode/electrolyte interface during cycling,which severely decreases the stability of crystalline structure and cathodeelectrolyte interphase and ultimately affects the calendar life of batteries.Herein,a thermodynamically stabilized interface is constructed on the surface of single-crystalline Ni-rich cathode materials(SC811@RS)via a facile molten-salt route to suppress the generation of microcracks and interfacial parasitic side reactions simultaneously.Density functional theory calculations show that the formation energy of interface layer(−1.958 eV)is more negative than that of bulk layered structure(−1.421 eV).Such a thermodynamically stable protective layer can not only prevent the direct contact between highly reactive LiNi_(x)Co_(y)Mn_(1−x−y)O_(2)and electrolyte,but also mitigate deformation of structure caused by stress thus strengthening the mechanical properties.Raman spectra further confirm the excellent structural reversibility and reaction homogeneity of SC811@RS at particle,electrode,time scales.Consequently,SC811@RS cathode material delivers significantly improved cycling stability(high capacity retention of 92%after 200 cycles at 0.5 C)compared with polycrystalline LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(82%).

关 键 词：LiNi_(x)Co_(y)Mn_(1−x−y)O_(2) single crystalline polycrystalline cathode lithium-ion battery 

分 类 号：TB383[一般工业技术—材料科学与工程]