Coupling effect of the conductivities of Li ions and electrons by introducing LLTO@C fibers in the LiNi0.8Co0.15Al0.05O2 cathode  

作　　者：Hao-yang Wang Xue Cheng Xiao-feng Li Ji-min Pan Jun-hua Hu 

机构地区：[1]School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,China [2]State Center for International Cooperation on Designer Low-carbon&Environmental Materials(CDLCEM),Zhengzhou University,Zhengzhou 450001,China [3]Zhengzhou Materials Genome Institute(ZMGI),Xingyang 450100,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2021年第2期305-316,共12页矿物冶金与材料学报（英文版）

基　　金：This work was financially supported by the National Natural Science Foundation of China(Nos.51571182 and 51001091);the Fundamental Research Program from the Ministry of Science and Technology of China(No.2014CB931704);the Program for Innovative Research Team(in Science and Technology)in University of Henan Province(No.21IRTSTHN003).This work was also partially supported by the Provincial Scientific Research Program of Henan(No.182102310815).

摘　　要：To probe the coupling effect of the electron and Li ion conductivities in Ni-rich layered materials(LiNi0.8Co0.15Al0.05O2,NCA),lithium lanthanum titanate(LLTO)nanofiber and carbon-coated LLTO fiber(LLTO@C)materials were introduced to polyvinylidene difluoride in a cathode.The enhancement of the conductivity was indicated by the suppressed impedance and polarization.At 1 and 5 C,the cathodes with coupling conductive paths had a more stable cycling performance.The coupling mechanism was analyzed based on the chemical state and structure evolution of NCA after cycling for 200 cycles at 5 C.In the pristine cathode,the propagation of lattice damaged regions,which consist of high-density edge-dislocation walls,destroyed the bulk integrity of NCA.In addition,the formation of a rock-salt phase on the surface of NCA caused a capacity loss.In contrast,in the LLTO@C modified cathode,although the formation of dislocation-driven atomic lattice broken regions and cation mixing occurred,they were limited to a scale of several atoms,which retarded the generation of the rock-salt phase and resulted in a pre-eminent capacity retention.Only NiO phase“pitting”occurred.A mechanism based on the synergistic transport of Li ions and electrons was proposed.

关 键 词：Ni-rich cathode coupling mechanism dislocation wall coaxial structure cation mixing 

分 类 号：TM912[电气工程—电力电子与电力传动]