This review comprehensively summarizes the progress on the structural and electronic modulation of transition metal nitrides for electrochemical energy applications.

Graphene has attracted extensive interest in the field of supercapacitor research due to its 2D structure which grants it exceptional properties such as superior electrical conductivity and mechanical properties as well as an extensive surface area better than that of carbon nanotubes (CNTs). Furthermore, unlike other carbon materials, graphene is particularly optimal for supercapacitor applications as its surface area does not vary with pore size distribution and grants electrolyte access to both its surfaces. This article aims to review the advances in recent research and development of the use of graphene for supercapacitor use. The focus would mainly be on the areas of graphene synthesis, graphene modification, graphene–nanoporous carbon composites, graphene–polymer composites and graphene–metal oxides and their potential use in both asymmetric and symmetric supercapacitors. Lastly, the article aims to identify optimal testing methods for electrode performance and choice of electrolytes. It will then stress the increasing need to standardise electrode testing to ensure that test results are as relevant to real life applications as possible.

2D metals, metallenes, feature exciting opportunities at the forefront of electrocatalysis. We bring to attention metallene preparation techniques and modification strategies for the derivation of highly functional metallenes in key electrocatalytic applications.