Applications of graphene in energy storage devices: From fundamental research to engineering practice

The energy and environmental concerns drive the development of innovative energy storage systems, such as lithium-based batteries and supercapacitors. Owing to its highly appealing properties including excellent conductivity, ultra-large specific surface area, outstanding mechanical properties, etc., extensive application research of graphene in electrochemical energy storage has been explored. Despite widespread enthusiasm, a general and objective comprehension of the actual role of graphene in energy storage devices is still lacking, moreover, it remains uncertain if graphene could truly result in practical progress of this field. In this review, we give a basic introduction on the properties and scalable preparation methods of graphene. Starting from the connection between graphene properties and its potential applications in the field of electrochemical energy storage, the relationship between synthesis-structure-property-application of graphene is considered, enabling optimal alignment between graphene production and device performance. And then according to the role that graphene mainly plays in the energy storage devices and years of research practices, we comprehensively review the state-of-the-art applications of graphene from laboratory-scale research to engineering practice, both as inactive components including conductive additive, current collector (modifier) in electrodes and active materials including energy storage material and modulator of active materials. We aim to discuss the advantages and challenges associated with graphene in the practical application, as well as highlight the most promising outcomes and uses of graphene in electrochemical energy storage devices so far to guide directions on how graphene can further contribute to the development of this field in the future.