Field-assisted metal-air batteries: Recent progress, mechanisms, and challenges

Metal-air batteries are recognized as a next-generation solution for energy storage with high energy density and environmental protection. However, the development of air batteries has been severely limited due to slow cathodic kinetics, which result in large overpotentials and low round-trip efficiency. In recent years, the research on field assisted metal-air batteries has garnered increasing attention. This review systematically discusses the impact of optical fields, magnetic fields, ultrasonic fields, internal stress fields, microwave fields, and composite fields on the charging and discharging processes of air batteries. Optical fields possess the ability to excite electrons within electrode materials, alternatively transforming light energy into heat, which consequently facilitates electrochemical reactions. Magnetic fields have the potential to change the orientation of the magnetic moment in electrode materials, affecting reaction rates and mass transfer processes. By introducing ultrasonic fields and internal stress fields, the kinetic processes of electrocatalytic reactions can be optimized. Microwave fields can improve the synthesis strategies of electrode materials. These external fields improve the performance and efficiency of metal-air batteries by effectively regulating the physical state, reaction rates, and mass transfer processes of electrode materials. Finally, the main challenges and possible future research directions for external field regulation strategies are summarized.