The emergence of a robust lithium gallium oxide surface layer on gallium-doped LiNiO2 cathodes enables extended cycling stability
Date
2024-08-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Materials Advances
Abstract
LiNiO2 is a promising cobalt-free cathode for lithium-ion batteries due to its high theoretical capacity and low cost. Although intensely studied, the occurrence of several phase transformations and particle pulverization causing capacity fading in cobalt-free LiNiO2 have yet to be effectively resolved. Herein, a sol–gel synthesis process is utilized for gallium (Ga) doping of LiNiO2 at 2% (solution-doping) and 5% (excess-doping) molar ratios. Transmission electron microscopy and X-ray diffraction Rietveld refinement reveal the opportune formation of an α-LiGaO2 shell at 5% doping beyond the solubility limit of 2%. Alongside solution-doping at the Ni and Li crystallographic sites, the emergence of this α-LiGaO2, isostructural and lattice-matched to the R[3 with combining macron]m LiNiO2, is shown to improve capacity retention by a factor of 2.45 after 100 cycles at C/3. Particles with the LiGaO2 shell experience significantly less pulverization during extended cycling. In contrast, the solution-doped LiNiO2 with 2% Ga experiences extensive particle fracturing similar to the baseline undoped LiNiO2. In turn, no significant electrochemical performance difference is found between the solution-doped and baseline LiNiO2. The evidence garnered suggests that a surface gallium oxide phase achievable with excess Ga is key to enabling extended cycling using Ga doping.
Description
This article was originally published in Materials Advances. The version of record is available at: https://doi.org/10.1039/D3MA01102J. © 2024 The Author(s). Published by the Royal Society of Chemistry
Keywords
Citation
Mishra, Mritunjay, and Koffi P. C. Yao. “The Emergence of a Robust Lithium Gallium Oxide Surface Layer on Gallium-Doped LiNiO 2 Cathodes Enables Extended Cycling Stability.” Materials Advances, 2024, 10.1039.D3MA01102J. https://doi.org/10.1039/D3MA01102J.