Intergranular Cracking as a Major Cause of Long-Term Capacity Fading of Layered Cathodes

• DOI: 10.1021/acs.nanolett.7b00379
• Publication Date: 2017-05-26T17:50:29Z
• Authors: Hao Liu; Mark Wolfman; Khim Karki; Young-Sang Yu; Eric A. Stach; Jordi Cabana; Karena W. Chapman; Peter J. Chupas
• Keywords: Fade; Capacity loss

Capacity fading has limited commercial layered Li-ion battery electrodes to <70% of their theoretical capacity. Higher capacities can be achieved initially by charging higher voltages, however, these gains are eroded a faster fade in Increasing lifetimes and reversible capacity contingent on identifying the origin this inform electrode design synthesis. We used operando X-ray diffraction observe how lithiation-delithiation reactions within LiNi0.8Co0.15Al0.05O2 (NCA) change after following months slow charge-discharge. The changes that underpin energy storage long-term cycling directly correlate loss; heterogeneous reaction kinetics observed during extended cycles quantitatively account for loss. This heterogeneity is ultimately attributed intergranular fracturing degrades connectivity subsurface grains polycrystalline NCA aggregate.