A Transformative Molecular Muscle Solid Electrolyte
Yuhang Liu, Zhangqin Shi, Xinyang Yue, Jun Zhao, Xinyang Zhao, Xiaoya He, Zhewen Guo, Zhaoming Zhang, Yujun Xie, Wei Yu, Xuzhou Yan, Zheng Liang
Abstract
Solid polymer electrolytes (SPEs) endow Li metal batteries (LMBs) with high expectations, but their real-world applications suffer from the “seesaw effect” between mechanical robustness and ionic conductivity. Herein, inspired by the myofilament sliding, we propose a molecular muscle SPE consisting of mechanically interlocked [ c 2]daisy chain ([ c 2]DC) networks ( DC MINs) to break the SPE bottleneck, demonstrating a superior room-temperature (RT) ionic conductivity of 1.04 mS cm –1 (no plasticizer) without sacrificing the mechanical properties. The dynamic [ c 2]DC units, in conjunction with host–guest interactions, strengthen the movement of soft poly(ethylene glycol) backbones that coordinate with Li ions to contribute to the improved Li-ion transport compared to the regular cross-linked polymer network. The intrinsically distinctive energy dissipation of DC MINs further facilitates the structural integrity of SPEs under the repeated deformation of Li metal anodes, restricting dendrite growth and thus ensuring a lifespan longer than 5000 h for Li symmetric cells. All-solid-state pouch LMBs (∼1 Ah) with muscle-inspired SPEs exhibit competitive performance at RT in terms of cycling stability (87.8% capacity retention after 750 cycles for the LiFePO 4 cell). We anticipate that our findings could spur investigations regarding high-performance SPE design for advanced solid-state batteries.