Supramolecular oscillation-assisted ion transport in solid electrolytes

Abstract

Solid-state electrolytes are crucial for electrochemical devices, yet the challenge of simultaneously enhancing both ionic conductivity and stability—rather than sacrificing one for the other—remains a critical issue. In this work, a high-performance solid polymer electrolyte (HP-SPE) membrane that successfully integrates exceptional stability with high ionic conductivity was developed. It is based on a polyvinyl butyral (PVB) matrix coupled with (3-glycidyloxypropyl)trimethoxysilane (KH560) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and was fabricated through an ultra-low residual solvent content drying (ULD) process. The high overall performance of HP-SPE was achieved through the binding of trace residual solvents within LiTFSI and the polymer matrix, a mechanism referred to as “supramolecular oscillation-assisted ion transport”. HP-SPE achieved an ionic conductivity of 10⁻⁵ S cm⁻¹ at 30 °C (for over two months). The decomposition temperature reached 250 °C, achieving a comprehensive improvement in both conductivity and stability. By applying the HP-SPE membrane to emerging electrochromic devices, these electrochromic devices achieved rapid color switching (3.1 s for coloration and 6.1 s for bleaching), uniform color transition, and steady-state operation without overheating for up to 160 hours, the best results reported to date. This work establishes HP-SPE as a versatile material platform, demonstrating immediate success in electrochromics and revealing significant potential for deployment in next-generation, high-safety solid-state batteries.