Branched Polyacrylonitrile Enabling Highly Lithium-Ion-Conductive Polymer Plastic Crystal Electrolytes.

Advancing the development of high-performance solid-state electrolytes is critical for realizing next-generation lithium metal batteries. Among promising candidates, polymer-succinonitrile composites have emerged as effective polymer plastic crystal electrolytes, demonstrating enhanced electrochemical performance. However, further improvements are needed to meet practical application requirements. In this study, we report a novel strategy for synthesizing electrochemically stable branched polyacrylonitrile through controlled/living branching radical polymerization, employing 2-chloroacrylonitrile as an innovative inibramer. The unique branched architecture of the resulting polymer facilitates continuous pathways, enabling rapid lithium-ion transport when incorporated in polymer plastic crystal electrolytes. Electrochemical characterization reveals substantial improvements in both ionic conductivity and stability compared to conventional linear counterparts. These findings highlight the pivotal role of polymer architectural design in optimizing ion transport within solid electrolytes, offering new opportunities for developing safer and more efficient energy storage devices.