A novelty strategy induced pinning effect and defect structure in Ni-rich layered cathodes towards boosting its electrochemical performance  

作　　者：Zhouliang Tan Yunjiao Li Xiaoming Xi Shijie Jiang Xiaohui Li Xingjie Shen Panpan Zhang Zhenjiang He Junchao Zheng 

机构地区：[1]School of Metallurgy and Environment,Central South University,Changsha 410083,Hunan,China [2]Engineering Research Center of the Ministry of Education for Advanced Battery Materials,Central South University,Changsha 410083,Hunan,China [3]Changsha Research Institute of Mining and Metallurgy,Changsha 410083,Hunan,China [4]Office of Laboratory and Equipment Management,Xinjiang University,Urumqi 830000,Xinjiang,China

出　　处：《Journal of Energy Chemistry》2022年第9期570-580,I0016,共12页能源化学（英文版）

基　　金：financially supported by the Science and Technology of Guangxi Zhuang Autonomous Region(the Guangxi special Fund for Scientific Center and Talent Resources:AD18281073,Chongke 2018AD15002 and FA2020011)。

摘　　要：Layered Ni-rich transition metal oxide is treated as the most promising alternative cathode due to their high-capacity and flexible composition.However,the severe lattice strain and slow Li-ion migration kinetics severely restrict their practical application.Herein,a novelty strategy induced pinning effect and defect structure in layered Ni-rich transition metal oxide cathodes is proposed via a facile cation(iron ion)/anion(polyanion)co-doping method.Subsequently,the effects of pinning effect and defect structure on element valence state,crystal structure,morphology,lattice strain,and electrochemical performance during lithiation/delithiation are systematically explored.The detailed characterizations(soft X-ray absorption spectroscopy(sXAS),in-situ X-ray diffraction(XRD),etc.)and density functional theory(DFT)calculation demonstrate that the pinning effects built-in LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)materials by the dual-site occupation of iron ions on lithium and transition metal sites effectively alleviate the abrupt lattice strain caused by an unfavorable phase transition and the subsequent induction of defect structures in the Li layer can greatly reduce the lithium-ion diffusion barrier.Therefore,the modified LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)exhibits a high-capacity of 206.5 mAh g^(-1)and remarkably enhanced capacity retention of 93.9%after 100 cycles,far superior to~14.1%of the pristine cathodes.Besides,an excellent discharge capacity of 180.1 mAh g^(-1)at 10 C rate is maintained,illustrating its remarkable rate capability.This work reports a pinning effect and defect engineering method to suppress the lattice strain and alleviate lithium-ion kinetic barriers in the Ni-rich layered cathodes,providing a roadmap for understanding the fundamental mechanism of an intrinsic activity modulation and structural design of layered cathode materials.

关 键 词：Ni-rich layered cathode Pinning effect Defect structure Lattice strain Lithium-ion kinetic 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ131.11[化学工程—无机化工]