Covalent Organic Framework Mediated Solvation in Quasi-Solid-State Polymer Electrolyte for High-Performance Silicon-Based Lithium-Ion Batteries
Tao Cai, Fei Zhao, Pushpendra Kumar, Hao Yu, Zexu Wang, Akang Huang, Wandi Wahyudi, Qian Li, Tianming Feng, Yingjun Guo, Zheng Ma, Jun Ming
Abstract
The practical application of solid polymer electrolytes (SPEs) is limited by their low ionic conductivity and poor interfacial compatibility with silicon (Si) anodes in high-energy-density, safe lithium-ion batteries (LIBs). Here, we introduce a lithiated covalent organic framework (COF) into a poly(vinylidene fluoride-cohexafluoropropylene) (PVDF-HFP)-based quasi-solid polymer electrolyte (QSPE) containing plasticizers to increase its electrochemical performance. The resulting COF-based QSPE has a high ionic conductivity of 2.99 mS cm –1 and enables Si anodes to deliver a remarkable specific capacity of 1722 mAh g –1 after 500 cycles, along with an excellent rate capability of up to 10 A g –1 . Furthermore, we provide new insights into the role of lithiated COFs in modulating the Li + solvation structure, facilitating ionic migration and promoting desolvation in plasticizer-containing solid electrolytes at the molecular scale. These findings offer valuable guidelines for the rational design of stable Si anodes in solid-state batteries.