Nature Communications (Aug 2023)

Multiscale dynamics of charging and plating in graphite electrodes coupling operando microscopy and phase-field modelling

  • Xuekun Lu,
  • Marco Lagnoni,
  • Antonio Bertei,
  • Supratim Das,
  • Rhodri E. Owen,
  • Qi Li,
  • Kieran O’Regan,
  • Aaron Wade,
  • Donal P. Finegan,
  • Emma Kendrick,
  • Martin Z. Bazant,
  • Dan J. L. Brett,
  • Paul R. Shearing

DOI
https://doi.org/10.1038/s41467-023-40574-6
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 14

Abstract

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Abstract The phase separation dynamics in graphitic anodes significantly affects lithium plating propensity, which is the major degradation mechanism that impairs the safety and fast charge capabilities of automotive lithium-ion batteries. In this study, we present comprehensive investigation employing operando high-resolution optical microscopy combined with non-equilibrium thermodynamics implemented in a multi-dimensional (1D+1D to 3D) phase-field modeling framework to reveal the rate-dependent spatial dynamics of phase separation and plating in graphite electrodes. Here we visualize and provide mechanistic understanding of the multistage phase separation, plating, inter/intra-particle lithium exchange and plated lithium back-intercalation phenomena. A strong dependence of intra-particle lithiation heterogeneity on the particle size, shape, orientation, surface condition and C-rate at the particle level is observed, which leads to early onset of plating spatially resolved by a 3D image-based phase-field model. Moreover, we highlight the distinct relaxation processes at different state-of-charges (SOCs), wherein thermodynamically unstable graphite particles undergo a drastic intra-particle lithium redistribution and inter-particle lithium exchange at intermediate SOCs, whereas the electrode equilibrates much slower at low and high SOCs. These physics-based insights into the distinct SOC-dependent relaxation efficiency provide new perspective towards developing advanced fast charge protocols to suppress plating and shorten the constant voltage regime.