Autonomous ion-highways quasi-solid electrolytes toward high-voltage lithium metal batteries

Huajun Li; Meiying Li; Suting Weng; Jingnan Feng; Jinming Yue; Jiacheng Zhu; Kaihui Nie; Xiangzhen Zhu; Liangdong Lin; Xuefeng Wang; Huican Mao; Hong Li; Xuejie Huang; Liquan Chen; Liumin Suo

doi:10.1093/nsr/nwaf363

Autonomous ion-highways quasi-solid electrolytes toward high-voltage lithium metal batteries

Natl Sci Rev. 2025 Aug 30;12(10):nwaf363. doi: 10.1093/nsr/nwaf363. eCollection 2025 Oct.

Authors

Huajun Li^{1

2}, Meiying Li^{1

2}, Suting Weng^{1

2}, Jingnan Feng^{1

2}, Jinming Yue^{1

2}, Jiacheng Zhu^{1

2}, Kaihui Nie^{1

2}, Xiangzhen Zhu^{1

2}, Liangdong Lin¹, Xuefeng Wang^{1

2}, Huican Mao³, Hong Li¹, Xuejie Huang¹, Liquan Chen¹, Liumin Suo^{1

2}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
³ Department of Materials Science and Key Laboratory of Automobile Materials, Ministry of Education, Jilin University, Changchun 130012, China.

Abstract

Electrolyte solidification holds great promise in addressing safety concerns. Nevertheless, integrating high electrochemical stability and intrinsic interfacial compatibility remains challenging for high-voltage lithium metal batteries. Herein, we report an ion-percolative quasi-solid electrolyte via concentration-driven self-assembly. At a concentration threshold (LiFSI(FEC)_x, x = 0.37), the system triggers spontaneous crystallization of LiFSI to form a rigid, nonflammable framework at room temperature and generates dispersed [LiFSI-FEC] ionic clusters that simultaneously percolate within grain boundaries. This unique ion-percolative architecture (nano-LiFSI skeleton + [LiFSI-FEC] cluster network) enables autonomous Li-ion highways between dynamic clusters along grain boundaries of salt. The optimized electrolyte achieves a high ionic conductivity of 2.3 × 10^-4 S/cm and an exceptional Li⁺ transference number (0.75) at room temperature. This electrolyte provides a satisfying tradeoff between nonflammability, electrochemical windows, ionic conductivity, and mechanical properties, simultaneously achieving perfect compatibility with the lithium metal anode and 4.6 V high-voltage cathodes.

Keywords: high-voltage cathode; ion-percolative electrolyte; lithium metal battery; solid state electrolyte.