Composite electrolyte with self‐inserted structure and all‐trans F conformation provides fast Li + transport for solid‐state Li metal batteries

作者：Ziyang Liang, Chang Liu, Xiang Bai, Jiahui Zhang, Xinyue Chang, Lixiang Guan, Tiantian Lu, Huayun Du, Yinghui Wei, Qian Wang, Tao Wei, Wen Liu, Henghui Zhou · 发表于：InfoMat · 年份：2024 · DOI：10.1002/inf2.12613 · 被引用次数：23 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Layered Double Hydroxides Synthesis and Applications

Abstract Solid‐state Li metal battery has attracted increasing interests for its potentially high energy density and excellent safety assurance, which is a promising candidate for next generation battery system. However, the low ionic conductivity and Li + transport number of solid‐state polymer electrolytes limit their practical application. Herein, a composite polymer electrolyte with self‐inserted structure is proposed using the layered double hydroxides (LDHs) as dopant to achieve a fast Li + transport channel in poly(vinylidene‐co‐trifluoroethylene) [P(VDF‐TrFE)] based polymer electrolyte. In such a composite electrolyte, P(VDF‐TrFE) polymer has an all‐trans conformation, in which all fluorine atoms locate on one side of the polymer chain, providing fast Li + transport highways. Meanwhile, the LDH can immobilize the anions of Li salts based on the electrostatic interactions, promoting the dissociation of Li salts, thereby enhancing the ionic conductivity (6.4 × 10 −4 S cm −1 ) and Li + transference number (0.76). The anion immobilization effect can realize uniform electric field distribution at the anode surface and suppress the dendritic Li growth. Moreover, the hydrogen bonding interaction between LDH and polymer chains also endows the composite electrolyte with strong mechanical properties. Thus, at room temperature, the Li || Li symmetric cells can be stably cycled over 1000 h at a current density of 0.2 mA cm −2 , and the full cells with LiFePO 4 cathode deliver a h...