Surface enrichment and diffusion enabling gradient-doping and coating of Ni-rich cathode toward Li-ion batteries

Haifeng Yu; Yueqiang Cao; Long Chen; Yanjie Hu; Xuezhi Duan; Sheng Dai; Chunzhong Li; Hao Jiang

doi:10.1038/s41467-021-24893-0

Surface enrichment and diffusion enabling gradient-doping and coating of Ni-rich cathode toward Li-ion batteries

Nat Commun. 2021 Jul 27;12(1):4564. doi: 10.1038/s41467-021-24893-0.

Authors

Haifeng Yu^#¹, Yueqiang Cao^#², Long Chen¹, Yanjie Hu¹, Xuezhi Duan², Sheng Dai³, Chunzhong Li¹, Hao Jiang⁴

Affiliations

¹ Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China.
² State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai, China.
³ Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China.
⁴ Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Engineering Research Center of Hierarchical Nanomaterials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China. jianghao@ecust.edu.cn.

^# Contributed equally.

Abstract

Critical barriers to layered Ni-rich cathode commercialisation include their rapid capacity fading and thermal runaway from crystal disintegration and their interfacial instability. Structure combines surface modification is the ultimate choice to overcome these. Here, a synchronous gradient Al-doped and LiAlO₂-coated LiNi_0.9Co_0.1O₂ cathode is designed and prepared by using an oxalate-assisted deposition and subsequent thermally driven diffusion method. Theoretical calculations, in situ X-ray diffraction results and finite-element simulation verify that Al³⁺ moves to the tetrahedral interstices prior to Ni²⁺ that eliminates the Li/Ni disorder and internal structure stress. The Li⁺-conductive LiAlO₂ skin prevents electrolyte penetration of the boundaries and reduces side reactions. These help the Ni-rich cathode maintain a 97.4% cycle performance after 100 cycles, and a rapid charging ability of 127.7 mAh g^-1 at 20 C. A 3.5-Ah pouch cell with the cathode and graphite anode showed more than a 500-long cycle life with only a 5.6% capacity loss.