Nitrogen-doped graphene materials for supercapacitor applications.

Development of advanced functional materials for energy conversion and storage technologies play a key role in solving the problems of the rapid depletion of fossil fuels and increasingly worsened environmental pollution caused by vast fossil-fuel consumption. Supercapacitors (SCs), also known as ultracapacitors, which store energy based on either ion adsorption or fast/reversible faradaic reactions, are supposed to be a promising candidate for alternative energy storage devices due to their high rate capability, pulse power supply, long cycle life, simple principles, high dynamics of charge propagation, and low maintenance cost. The performance of supercapacitors highly depends on the properties of electrode materials. Nitrogen-doped graphene (NG)-based materials exhibit great potential for application in supercapacitors because of their unique structure and excellent intrinsic physical properties, such as large surface area with appropriate pore structure, controllable two- or three-dimensional morphology, and extraordinarily electrical conductivity. In this review, we provide a brief summary of recent research progress on NG-based electrode materials for SCs, including the various synthesis methods and the mechanisms of electrochemical performance enhancement.