Polymer electrolyte solid-state lithium batteries beyond 500 Wh kg−1: challenges and advances

Achieving an energy density exceeding 500 Wh kg −1 is an urgent goal for the development of next-generation lithium-ion batteries, and polymer solid-state electrolytes have emerged as a key breakthrough due to their excellent interfacial compatibility and processability. However, under extreme conditions, issues such as oxidative decomposition at the cathode/electrolyte interface, reduction reaction at the anode/electrolyte interface, and the slow ion transport kinetics in the bulk of polymer electrolytes severely limit battery performance. This review systematically summarizes the role of cutting-edge research on the three core challenges mentioned above in optimizing interfacial stability and ion transport. The key parameters and representative systems of Ah-class pouch cells with energy densities exceeding 500 Wh kg −1 are then summarized. Finally, the development trends in advanced materials design, in-situ characterization technologies and device engineering are outlined, with a goal of providing a systematic framework for the rational design and engineering applications of high-energy-density solid-state lithium polymer batteries.