A review of 3D graphene materials for energy storage and conversion

Abstract

Three-dimensional (3D) graphene monoliths are a new carbon material, that has tremendous potential in the fields of energy conversion and storage. They can solve the limitations of two-dimensional (2D) graphene sheets, including interlayer restacking, high contact resistance, and insufficient pore accessibility. By constructing interconnected porous networks, 3D graphenes not only retain the intrinsic advantages of 2D graphene sheets, such as high specific surface area, excellent electrical and thermal conductivities, good mechanical properties, and outstanding chemical stability, but also enable efficient mass transport of external fluid species. We summarize the fabrication methods for 3D graphenes, with a particular focus on their applications in energy-related systems. Techniques including chemical reduction assembly, chemical vapor deposition, 3D printing, chemical blowing, and zinc-tiered pyrolysis have been developed to change their pore structure and elemental composition, and ways in which they can be integrated with functional components. In terms of energy conversion and storage, they have found broad use in buffering mechanical impacts, suppressing noise, photothermal conversion, electromagnetic shielding and absorption. They have also been used in electrochemical energy systems such as supercapacitors, secondary batteries, and electrocatalysis. By reviewing recent progress in structural design and new applications, we also discuss the problems these materials face, including scalable fabrication and precise pore structure control, and possible new applications.