A self-catalyzed strategy towards facile fabrication of bottlebrush polyester-based solid polymer electrolytes

As the hope of solving the safety problems of lithium metal batteries (LMBs), solid polymer electrolytes (SPEs) with controlled structures are receiving more and more attentions for constructing high-performance LMBs. Herein, we design and synthesize a brush-typed poly(ε-caprolactone) (PCL)-based electrolyte, and discuss the influence of the structure of the brush-typed polymer on the performance of the prepared SPEs. We first design a macromolecular precursor that can both initiate and catalyze the ring-opening polymerizations (ROPs) of cyclic lactones, and brush-typed polyesters are obtained via a self-catalyzed strategy. The carboxyl groups attached to the main chain of macromolecular precursor can catalyze ROPs of cyclic lactones and effectively inhibit the growth of irregular lithium dendrites. Due to the well-designed brush structure and flexible PCL side chain, the SPE exhibits an ideal ionic conductivity of 5.53 × 10−5 S cm−1 at room temperature and a high tLi+ of 0.82 at 60 °C. The self-catalyzed strategy provides a promising method to fabricate high-performance SPEs for ambient-temperature LMBs.