▎ 摘　　要

While almost all attempts for bulk synthesis of graphene result in agglomeration of flat graphene layers, a simple solvothermal route is reported for the preparation of a graphene powder consisting of very flexible sheets. Curvature of these graphene sheets avoids vital agglomeration, which normally blocks the accessible surface of graphene sheets. The thickness of the graphene sample varies from one to a few layers, but the spaces among the graphene layers are sufficiently large enough to provide internal accessibility. Thus, this graphene sample shows the general (bulk) properties of graphene single sheets. For instance, it has a high specific surface area of ca. 1168 m(2) g(-1) and starts to burn at 350 degrees C because of a large interlayer spacing of graphene sheets (i.e., 5.1 angstrom). It should be considered that this specious interlayer is mostly due to the graphene curvature rather than to filling with functional groups (as in the case of graphite oxide). Owing to the high accessibility and active sites over a large surface area, this graphene sample shows a superior electrochemical behavior for hydrogen storage.