Coupling of electrochemically triggered thermal and mechanical effects to aggravate failure in a layered cathode

作者：Pengfei Yan, Jianming Zheng, Tianwu Chen, Langli Luo, Yuyuan Jiang, Kuan Wang, Manling Sui, Ji‐Guang Zhang, Sulin Zhang, Chongmin Wang · 发表于：Nature Communications · 年份：2018 · DOI：10.1038/s41467-018-04862-w · 被引用次数：306 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Advanced battery technologies research

Abstract Electrochemically driven functioning of a battery inevitably induces thermal and mechanical effects, which in turn couple with the electrochemical effect and collectively govern the performance of the battery. However, such a coupling effect, whether favorable or detrimental, has never been explicitly elucidated. Here we use in situ transmission electron microscopy to demonstrate such a coupling effect. We discover that thermally perturbating delithiated LiNi 0.6 Mn 0.2 Co 0.2 O 2 will trigger explosive nucleation and propagation of intragranular cracks in the lattice, providing us a unique opportunity to directly visualize the cracking mechanism and dynamics. We reveal that thermal stress associated with electrochemically induced phase inhomogeneity and internal pressure resulting from oxygen release are the primary driving forces for intragranular cracking that resembles a “popcorn” fracture mechanism. The present work reveals that, for battery performance, the intricate coupling of electrochemical, thermal, and mechanical effects will surpass the superposition of individual effects.