<p>This paper reviews the research progress, fundamental principles, and structural features of electrochemical flow capacitors (EFCs), as well as their application prospects in energy storage. It begins by introducing the development of energy storage technologies and highlights the purpose and significance of EFCs. The working mechanism and key components of EFCs are elaborated, and a comparison with other energy storage technologies underscores the unique advantages of EFCs. Major technical challenges are discussed, including electrode material selection, electrolyte composition and optimization, separator limitations, and system design with consideration of fluid dynamics. Corresponding solutions are proposed, such as developing high-performance electrode materials, designing efficient electrolytes, improving separator selectivity, and optimizing system architecture for higher energy density. Furthermore, the paper explores application cases and market potential in renewable energy integration, grid regulation, portable devices, and electric vehicles. Finally, future research directions are outlined, covering advanced materials, system integration, smart management strategies, and sustainability assessments. Despite existing challenges, EFCs demonstrate strong potential for broad application in future energy storage systems through continued innovation.</p>