Tremendous efforts have been dedicated into the development of high‐performance energy storage devices with nanoscale design and hybrid approaches. The boundary between the electrochemical capacitors and batteries becomes less distinctive. The same material may display capacitive or battery‐like behavior depending on the electrode design and the charge storage guest ions. Therefore, the underlying mechanisms and the electrochemical processes occurring upon charge storage may be confusing for researchers who are new to the field as well as some of the chemists and material scientists already in the field. This review provides fundamentals of the similarities and differences between electrochemical capacitors and batteries from kinetic and material point of view. Basic techniques and analysis methods to distinguish the capacitive and battery‐like behavior are discussed. Furthermore, guidelines for material selection, the state‐of‐the‐art materials, and the electrode design rules to advanced electrode are proposed.

Graphene is an emerging carbon material that may soon find practical applications. With its unusual properties, graphene is a potential electrode material for electrochemical energy storage. This article highlights recent research progress in graphene-based materials as supercapacitor electrodes. With a brief description of the working principle of supercapacitors, research progress towards the synthesis and modification of graphene-based materials, including graphene oxide, fullerenes, and carbon nanotubes, is presented. Applications of such materials with desirable properties to meet the specific requirements for the design and configuration of advanced supercapacitor devices are summarized and discussed. Future research trends towards new approaches to the design and synthesis of graphene-based nanostructures and architectures for electrochemical energy storage are proposed.

The recent progress, challenges and promising future on design, synthesis and fabrication of MnO ₂ for supercapacitors are reviewed and discussed.