Highly Stable Organic Molecular Porous Solid Electrolyte with One-Dimensional Ion Migration Channel for Solid-State Lithium-Oxygen Battery.

Abstract

Solid-state lithium-oxygen (Li-O₂) batteries have been widely recognized as one of the candidates for the next-generation of energy storage batteries. However, the development of solid-state Li-O₂ batteries has been hindered by the lack of solid-state electrolyte (SSE) with high ionic conductivity at room temperature, high Li⁺ transference number, and the high stability to air. Herein, the organic molecular porous solid cucurbit[7]uril (CB[7]) with one-dimensional (1D) ion migration channels is developed as the SSE for solid-state Li-O₂ batteries. Taking advantage of the 1D ion migration channel for Li⁺ conduction, CB[7] SSE achieves high ionic conductivity (2.45 × 10^-4 S cm^-1 at 25 °C). Moreover, the noncovalent interactions facilitated the immobilization of anions, realizing a high Li⁺ transference number (t_Li ⁺ = 0.81) and Li⁺ uniform distribution. The CB[7] SSE also shows a wide electrochemical stability window of 0-4.65 V and high thermal stability and chemical stability, as well as realizes stable Li⁺ plating/stripping (more than 1000 h at 0.3 mA cm^-2). As a result, the CB[7] SSE endows solid-state Li-O₂ batteries with superior rate capability and long-term discharge/charge stability (up to 500 h). This design strategy of CB[7] SSE paves the way for stable and efficient solid-state Li-O₂ batteries toward practical applications.