Supercapacitors for energy storage: Fundamentals and materials design

Abstract

Supercapacitors are among the most promising electrochemical energy-storage devices, bridging the gap between traditional capacitors and batteries in terms of power and energy density. Their charge-storage performance is largely influenced by the properties of electrode materials, electrolytes and the underlying charge-storage mechanisms. This review provides an overview of the fundamental principles of electrochemical energy storage in supercapacitors, highlighting various energy-storage materials and strategies for enhancing their performance, with a focus on manganese- and nickel-based materials. Key factors, such as electrode surface area, porosity and electrical conductivity are identified as critical contributors to performance. Approaches, such as nanostructuring, chemical activation and integration with conductive graphitic carbon or conducting polymers are extensively utilized to optimize these properties. The charge-storage performance of nanostructured Mn- and Ni-based materials investigated in our laboratory and the charge storage in nanoporous electrode are presented. Finally, the challenges and prospects of these materials for practical applications, including wearable and flexible supercapacitors, are discussed.

Graphical abstract

Electrochemical energy storage with supercapacitors using rationally designed electrode materials is reviewed.