Identifying the Degradation Mechanism in Commercial Lithium Rechargeable Batteries via High-Energy X-ray Compton Scattering Imaging

Synchrotron-based high-energy X-ray Compton scattering imaging is a promising technique for non-destructively and quantitatively investigating commercialized lithium rechargeable batteries. We apply the Compton scattering imaging technique to commercial coin-type lithium rechargeable cells (VL2020) to non-destructively identify the degradation mechanism of the cell. The correlations between the Compton scattering intensity and line-shape of the Compton scattering X-ray energy spectrum (S-parameter) obtained from this technique produce unique distributions that characterize the aged cell. These distributions in the aged cell indicate that the stable phase of the anode formed through the overvoltage charge–discharge cycle. This stable phase prevents lithium reactions, producing microbubbles with the decomposition of the electrolyte.