Although lithium-ion batteries have gained widespread use in high-performance and mobile industries, concerns about their safety due to the low boiling point of their organic liquid electrolyte have posed challenges to their further development. In response, solid polymer electrolytes have emerged as a promising alternative, characterized by low flammability, flexibility, and high safety relative to liquid electrolytes. However, commercialization has been hindered by limitations in Li-ion conductivity and mechanical properties. Recent research efforts have focused on addressing these limitations to improve the performance and safety of polymer-based Li-ion batteries. This review discusses the utilization of polymer materials to enhance battery safety and overcome previous challenges, with a particular emphasis on the design of robust artificial interfaces to increase battery stability. Furthermore, we discuss the prospects for the future of polymer-based battery industries.