Investigation of the mechanical flexibility and electrochemical stabilities of nanoporous materials consisting of single-layer graphene

Abstract

Graphene is a 2D material which has many fascinating features such as high theoretical surface area, mechanical properties and chemical stability. However, graphene sheets are easily stacked by π–π interaction, resulting in the loss of such unique properties. Thus, assembling graphene sheets into 3D architectures has been a challenge. Two unique 3D graphene-based porous materials, zeolite-templated carbon (ZTC) and graphene mesosponge (GMS), have been developed in Kyotani group. In this work, the mechanical flexibility and electrochemical properties of these nanoporous carbons are investigated, and its applications are developed. ZTC is an extremely soft but elastic microporous carbon, and its micropores are thus easily deformed by mechanical force. Herein, the control of gas adsorption in ZTC by applying mechanical force is demonstrated. Moreover, a new type of heat pump is proposed by utilizing the heat of adsorption as a thermal source. GMS is also an elastic material. Its pore can be reversibly compressed from 5.8 nm to 0.7 nm when a mechanical force (500 MPa) is applied on it. Additionally, GMS contains a very small amount of edge sites, which are only ca. 3% of commercial activated carbon. Hence, GMS shows an excellent electrochemical stability as an electrode for electric double-layer capacitors.