A comprehensive review of the 3D printing of sp2 carbons: Materials, properties and applications

Three dimensional (3D) printing is a modern technology that has the possibility to transform existing production methods. It offers a novel production method of layered manufacturing and layer-by-layer stacking, which radically simplifies the manufacturing process and enables large-scale customizable production. However, there are still numerous problems with this new technology. Except for pure graphene, sp(2) carbons can be 3D printed with little difficulty because of their hydrophilicity. The hydrophobic nature of pure graphene makes it difficult to print and process in water-based media, but advances in capillary inks allow for the 3D printing of pure graphene. This review focuses on the most recent developments in the 3D printing of sp(2) carbons. A concise overview of 3D printing technologies is presented, followed by a summary of 3D printed sp(2) carbons and their diverse applications. Finally, prospects and opportunities for this new field are discussed.