Physics of Energy Storage and Conversion Systems

Abstract

The global energy landscape is undergoing a transformation driven by the need for sustainable, efficient, and reliable energy storage and conversion technologies. Energy storage and conversion systems (ESCS) underpin renewable energy integration, electric mobility, and portable electronics. This review presents a comprehensive overview of the physics underlying major ESCS, including electrochemical batteries, supercapacitors, fuel cells, thermoelectric devices, and emerging systems such as redox flow batteries and solid-state devices. We examine the fundamental physical principles, material properties, device architectures, and operational mechanisms that govern energy storage and conversion. Comparative analyses highlight efficiency, energy/power density, cycle life, and practical applications, while identifying limitations and challenges. Finally, future directions are proposed, emphasizing material innovations, nanostructuring, interface engineering, and hybrid systems to meet evolving energy demands.