Oxygen Release Induced Chemomechanical Breakdown of Layered Cathode Materials

• DOI: 10.1021/acs.nanolett.8b01036
• Publication Date: 2018-04-18T15:55:19Z
• Authors: Linqin Mu; Ruoqian Lin; Rong Xu; Lili Han; Sihao Xia; Dimosthenis Sokaras; James D. Steiner; Tsu-Chien Weng; Dennis Nordlund; Marca M. Doeff; Yijin Liu; Kejie Zhao; Huolin L. Xin; Feng Lin
• Keywords: phase transformation; crack; Materials Engineering; Physical Chemistry; 01 natural sciences; 7. Clean energy; 0104 chemical sciences; Engineering; Chemical Sciences; Cathode; oxygen release; Nanoscience & Nanotechnology

Chemical and mechanical properties interplay on the nanometric scale collectively govern functionalities of battery materials. Understanding relationship between two can inform design materials with optimal chemomechanical for long-life lithium batteries. Herein, we report a mechanism nanoscale breakdown in layered oxide cathode materials, originating from oxygen release at high states charge under thermal abuse conditions. We observe that charged Li1–xNi0.4Mn0.4Co0.2O2 proceeds via two-step pathway involving intergranular intragranular crack formation. Owing to release, sporadic phase transformations structure spinel and/or rocksalt structures introduce local stress, which initiates microcracks along grain boundaries ultimately leads detachment primary particles, i.e., Furthermore, cracks (pores exfoliations) form, likely due accumulation vacancies continuous surfaces particles. Finally, finite element modeling confirms our experimental observation formation is attributable vacancies, transformations. This study designed directly behavior provides chemical basis strengthening secondary particles by stabilizing anions lattice.