Metal-Air Batteries: From Static to Flow System

As an emerging battery technology, metal-air flow batteries inherit the advantageous features of the unique structural design of conventional redox flow batteries and the high energy density of metal-air batteries, thus showing great potential as efficient electrochemical systems for large-scale electrical energy storage. This review summarizes the operating principles and recent progress of metal-air flow batteries from a materials and chemistry perspective, with particular emphasis on the latest advanced materials design and cell configuration engineering, which the authors divide into three categories based on the anode species: vanadium-air, zinc-air, and lithium-air flow batteries. Since some of the capabilities developed for metal-air static batteries can be leveraged for next-generation flow systems, classical works on conventional metal-air batteries are selected and compared with the metal-air flow systems, highlighting the prominent advantages of the latter in achieving high energy capacity and long cycle performance. At the end, a general perspective on current challenges/opportunities and future research directions to promote the commercial application of the metal-air flow battery technology is provided. The aim is to provide a comprehensive overview and to set up a road map for guiding development from conventional static to advanced flow technologies of metal-air batteries.