Molecular Self-Assembled Ether-Based Polyrotaxane Solid Electrolyte for Lithium Metal Batteries

Peipei Ding; Lingqiao Wu; Zhiyuan Lin; Chenjie Lou; Mingxue Tang; Xianwei Guo; Hongxia Guo; Yongtao Wang; Haijun Yu

doi:10.1021/jacs.2c06512

Molecular Self-Assembled Ether-Based Polyrotaxane Solid Electrolyte for Lithium Metal Batteries

J Am Chem Soc. 2023 Jan 25;145(3):1548-1556. doi: 10.1021/jacs.2c06512. Epub 2023 Jan 13.

Authors

Peipei Ding^{1

2}, Lingqiao Wu^{1

2}, Zhiyuan Lin^{1

2}, Chenjie Lou³, Mingxue Tang³, Xianwei Guo^{1

2}, Hongxia Guo^{1

2}, Yongtao Wang^{1

2}, Haijun Yu^{1

2}

Affiliations

¹ Institute of Advanced Battery Materials and Devices, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing100124, P. R. China.
² Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing100124, P. R. China.
³ Center for High Pressure Science & Technology Advanced Research, Beijing100094, P. R. China.

PMID: 36637214
DOI: 10.1021/jacs.2c06512

Abstract

Poly(ethylene oxide) has been widely investigated as a potential separator for solid-state lithium metal batteries. However, its applications were significantly restricted by low ionic conductivity and a narrow electrochemical stability window (<4.0 V vs Li/Li⁺) at room temperature. Herein, a novel molecular self-assembled ether-based polyrotaxane electrolyte was designed using different functional units and prepared by threading cyclic 18-crown ether-6 (18C6) to linear poly(ethylene glycol) (PEG) via intermolecular hydrogen bond and terminating with hexamethylene diisocyanate trimer (HDIt), which was strongly confirmed by local structure-sensitive solid/liquid-state nuclear magnetic resonance (NMR) techniques. The designed electrolyte has shown an obviously increased room-temperature ionic conductivity of 3.48 × 10^-4 S cm^-1 compared to 1.12 × 10^-5 S cm^-1 without assembling polyrotaxane functional units, contributing to the enhanced cycling stability of batteries with both LiFePO₄ and LiNi_0.8Co_0.15Al_0.05O₂ cathode materials. This advanced molecular self-assembled strategy provides a new paradigm in designing solid polymer electrolytes with demanded performance for lithium metal batteries.