Quantification of Heterogeneous Degradation in Li-Ion Batteries

• Published in: Advanced energy materials 2019-05, Vol.9 (25)
• Main Authors: Yang, Yang, Xu, Rong, Zhang, Kai, Lee, Sang‐Jun, Mu, Linqin, Liu, Pengfei, Waters, Crystal K., Spence, Stephanie, Xu, Zhengrui, Wei, Chenxi, Kautz, David J., Yuan, Qingxi, Dong, Yuhui, Yu, Young‐Sang, Xiao, Xianghui, Lee, Han‐Koo, Pianetta, Piero, Cloetens, Peter, Lee, Jun‐Sik, Zhao, Kejie, Lin, Feng, Liu, Yijin
• Format: Article
• Language: English
• Subjects: chemomechanical interplay; ENERGY STORAGE; fast charging; finite elemental modeling; NMC cathode; structural degradation; X‐ray phase contrast tomography
• ISSN: 1614-6832; 1614-6840

The multiscale chemomechanical interplay in lithium-ion batteries builds up mechanical stress, provokes morphological breakdown, and leads to state of charge heterogeneity. Quantifying the interplay in complex composite electrodes with multiscale resolution constitutes a frontier challenge in precisely diagnosing the fading mechanism of batteries. In this work, hard X-ray phase contrast tomography, capable of nanoprobing thousands of active particles at once, enables an unprecedented statistical analysis of the chemomechanical transformation of composite electrodes under fast charging conditions. The damage heterogeneity is demonstrated to prevail at all length scales, which stems from the unbalanced electron conduction and ionic diffusion, and collectively leads to the nonuniform utilization of active particles spatially and temporally. This research highlights that the statistical mapping of the chemomechanical transformation offers a diagnostic method for the particles utilization and fading, hence could improve electrode formulation for fast-charging batteries.