Graphene holds great potential for many applications due to its exceptional mechanical, thermal, and electrical properties. Integrating graphene macrostructures into external systems can speed up the industrialization of graphene. Therefore, assembling graphene sheets into desired macrostructures becomes quite important. Here we present our progress in fabricating various graphene macrostructures using different strategies. Compact graphene with various shapes and high density can be easily fabricated using a pH-mediated hydrothermal reduction method. This compact graphene has a compressive strength of ~360 MPa, which is 6 times higher than conventional graphite products. In addition, spongy graphene with porous structures can be produced through hydrothermal reduction and freeze drying, in which microstructures and properties of spongy graphene could be easily tailored by controlling the freezing temperatures. Moreover, drop-casting and dip coating have been used to produce graphene oxide films, and based on these films, we have successfully fabricated capacitive humidity sensors with ultrahigh humidity sensitivity and resistive humidity sensors with ultrafast response time, respectively. What is more, we propose a strategy that uses the synergistic effects of spraying coating and heating to easily prepare graphene films with controllable structures. Through controlling the temperature of the substrate, the microstructures of the graphene films can be tailored from layered structures to porous structure with different pore size.

Graphene holds great potential for many applications due to its exceptional mechanical, thermal, and electrical properties. Integrating graphene macrostructures into external systems can speed up the industrialization of graphene. Therefore, assembling graphene sheets into desired macrostructures becomes quite important. Here we present our progress in fabricating various graphene macrostructures using different strategies. Compact graphene with various shapes and high density can be easily fabricated using a pH-mediated hydrothermal reduction method. This compact graphene has a compressive strength of ~360 MPa, which is 6 times higher than conventional graphite products. In addition, spongy graphene with porous structures can be produced through hydrothermal reduction and freeze drying, in which microstructures and properties of spongy graphene could be easily tailored by controlling the freezing temperatures. Moreover, drop-casting and dip coating have been used to produce graphene oxide films, and based on these films, we have successfully fabricated capacitive humidity sensors with ultrahigh humidity sensitivity and resistive humidity sensors with ultrafast response time, respectively. What is more, we propose a strategy that uses the synergistic effects of spraying coating and heating to easily prepare graphene films with controllable structures. Through controlling the temperature of the substrate, the microstructures of the graphene films can be tailored from layered structures to porous structure with different pore size.