Mechanically Adaptive Cathode–Electrolyte Interphase via Dynamic Covalent Chemistry for Long-Life Ni-Rich Lithium Batteries
Yongtao Li, Y.W. Ye, Zixin Xie, Xu‐Dong Zhang, Xusheng Zhang, Changhui Ke, Zi‐Han Zhang, Rui Wen, Hui Yang, Huan Ye, Feifei Cao
Abstract
(NCM83) cathodes suffer from interfacial instability resulting from cathode-electrolyte reactions and anisotropic mechanical strain within secondary particles. Herein, we present a mechanically adaptive cathode-electrolyte interphase (CEI) engineered via a dynamic covalent network that features a supramolecular ion-conducting polyurethane ureido-pyrimidinone (SPU-UPy) elastomer. The dynamic network integrates cooperative hydrogen bonds and disulfide bonds and imparts exceptional mechanical resilience and autonomous self-healing capabilities that allow it to accommodate volume fluctuations without compromising structural integrity. The SPU-UPy layer is also designed with strong transition metal ion-O/N coordination bonds that greatly enhance adhesion to the NCM83 surface and mitigate transition metal dissolution in the electrolyte. The polyether backbone facilitates efficient Li-ion transport across the interface and ensures a homogeneous interfacial Li concentration during intercalation/deintercalation. Consequently, the dynamic CEI-coated NCM83 cathodes achieve exceptional long-term cycling stability with a high-capacity retention of 82.2% after 400 cycles at 1 C. This work elucidates the critical role of dynamic covalent chemistry in stabilizing Ni-rich cathode interfaces and establishes a new paradigm for the design of high-energy-density batteries through mechano-adaptive interfacial engineering.