Abstract
The simultaneous boosting of the ionic conductivity and the mechanical strength of an ionogel electrolyte is hindered by its entrapped electrolyte. Herein, we report a promising strategy to boost the mechanical strength of an ionogel by coating it with an ultrathin layer of polyanions and polycations via layer-by-layer (LbL) assembly. The essence of our strategy is to make use of the intrinsic ionic structure of an ionogel membrane for facile LbL construction of a membrane electrolyte interface. The resulting ultrathin LbL coating enhanced the mechanical strength of the electrolyte 5-fold while maintaining its high ionic conductivity (∼10–4 S cm–1 at 10 °C). The preliminary Li||LbL-LiNaf||LFP cell experiments exhibit promising electrochemical performance. This result is a significant development that will lead to the fabrication of robust membranes with liquid-like conductivity for lithium metal batteries.