Polydopamine-Induced Metal–Organic Framework Network-Enhanced High-Performance Composite Solid-State Electrolytes for Dendrite-Free Lithium Metal Batteries

Abstract

Due to the high safety, flexibility, and excellent compatibility with lithium metals, composite solid-state electrolytes (CSEs) are the best candidates for next-generation lithium metal batteries, and the construction of fast and uniform Li⁺ transport is a critical part of the development of CSEs. In this paper, a stable three-dimensional metal-organic framework (MOF) network was obtained using polydopamine as a medium, and a high-performance CSE reinforced by the three-dimensional MOF network was constructed, which not only provides a continuous channel for Li⁺ transport but also restricts large anions and releases more mobile Li⁺ through a Lewis acid-base interaction. This strategy endows our CSEs with an ionic conductivity (7.1 × 10^-4 S cm^-1 at 60 °C), a wide electrochemical window (5.0 V), and a higher Li⁺ transfer number (0.54). At the same time, the lithium symmetric batteries can be stably cycled for 2000 h at 0.1 mA cm^-2, exhibiting excellent electrochemical stability. The LiFePO₄/Li cells have a high initial discharge specific capacity of 153.9 mAh g^-1 at 1C, with a capacity retention of 80% after 915 cycles. This paper proposes an approach for constructing three-dimensional MOF network-enhanced CSEs, which provides insights into the design and development of MOFs for the positive effects of high-performance CSEs.