Advances in polymer electrolytes for solid-state zinc-air batteries

With the rapid development in flexible and wearable electronic devices, there is an urgent demand for soft power supplies with high energy density and long service life. In the emerging battery field, a safe, environmentally friendly, and low-cost zinc-air battery can store relatively high electrochemical energy (1084 W h kg⁻¹). Therefore, rechargeable zinc-air batteries may become a mainstream trend in the future. As an important part of a solid or quasi-solid-state battery, the performance of the polymer electrolyte directly affects the output performance, cycle stability, and working life of the battery. Therefore, the development of high-quality polymer electrolytes is of great significance for the maturity, scale, and practical application of flexible batteries. In addition, owing to the semi-open configuration and contact structure of flexible zinc-air batteries, interface compatibility between polymer electrolytes and electrodes (zinc electrode and air electrode) is an important factor affecting battery performance. Simultaneously, considering the characteristics of alkaline polymer electrolytes widely used at present, carbon dioxide (CO₂) components in the environment also interfere with the running state of the battery, thus weakening the battery's performance. CO₂-tolerance has become a key research direction for zinc-air batteries. Based on previous studies on zinc-air batteries, this study reviews the working principle of zinc-air batteries, lists the general assembly structure of the solid zinc-air battery, and based on this summarizes the current outstanding and superior characteristics of polymer electrolytes and the corresponding performance of the solid battery, as well as the interface problems of zinc electrode-electrolyte and air electrode-electrolyte. A new prospect for the future research and development of high-performance solid zinc-air batteries is proposed.