Graphene oxide-based materials as proton-conducting membranes for electrochemical applications

The rapid advancements of graphene oxide (GO)-based membranes necessitate the understanding of their properties and application potential. Generally, proton (H⁺)-conducting membranes, including GO-based ones, are crucial components in various energy-relevant devices, significantly determining the transport process, selectivity, and overall efficiency of these devices. Particularly, GO-based membranes exhibit great potential in electrochemical applications owing to their remarkable conductivity and ease of undergoing further modifications. This review is aimed at highlighting recent functionalization strategies for GO with diverse substrates. It is also aimed at emphasizing how these modifications can enhance the electrochemical performances of GO-based membranes. Notably, key aspects, such as the enhanced H⁺-transfer kinetics, improved conductivity, functionalities, and optimization, of these membranes for specific applications are discussed. Additionally, the existing challenges and future directions for the field of functionalized GO are addressed to achieve precise control of the functionalities of these membranes as well as advance next-generation electrochemical devices.