A review of the high-concentration processing, densification, and applications of graphene oxide and graphene

Dense graphene assemblies, composed of tightly stacked graphene sheets, have outstanding chemical stability and excellent mechanical, thermal, and electrical properties. They also do not have the problems of low density, low mechanical strength, poor electrical conductivity, or poor thermal conductivity found in porous graphene aerogels, making them ideal materials for future portable electronic and smart devices. We summarize work on high-concentration graphene oxide (GO) and graphene dispersions prepared by mechanical dispersion, evaporation concentration, centrifugal concentration, and liquid phase exfoliation, as well as two-dimensional (2D) dense graphene-based films and three-dimensional (3D) dense graphene-based structures prepared by vacuum-assisted filtration, interfacial self-assembly, and press-forming, and evaluate the advantages and disadvantages of each method. The applications of dense graphene-based assemblies in energy storage, thermal management, and electromagnetic interference (EMI) shielding are summarized. Finally, their challenges and prospects in future research are outlined. This review provides a reference for exploring and developing their large-scale, cost-effective manufacture and use.