No abstract

An improved hydrothermal process is developed to fabricate macroporous graphene monoliths (MGMs) using a soft template of organic droplets. The MGMs are constructed from closed-cell distorted spherical pores. This unique microstructure makes MGMs that have low weight densities, good electrical conductivities, and excellent elasticity with rapid recovery rates.

Graphene hydrogel/nickel foam composite electrodes for high-rate electrochemical capacitors are produced by reduction of an aqueous dispersion of graphene oxide in a nickel foam (upper half of figure). The micropores of the hydrogel are exposed to the electrolyte so that ions can enter and form electrochemical double-layers. The nickel framework shortens the distances of charge transfer. Therefore, the electrochemical capacitor exhibits highrate performance (see plots).

No abstract

Electrochemical capacitors (ECs) have been widely applied in electronics, electric vehicles, aircrafts, energy storage devices, uninterrupted or emergency power supplies, and so on. An ideal EC should have high energy and/or powder density, good rate capability, and long cycling life. Recently, graphene, graphene derivatives, and their composites have been explored as the electrode materials of ECs to satisfy these requirements. In this Perspective, we review the recent development in synthesizing graphene materials for ECs and discuss the strategies of fabricating graphene-based macroscopic electrodes. Particularly, we highlight the importance of the specific surface area, conductivity, and heteroatom-doping of graphene sheets and the micro/nanostructures of their electrodes for controlling the performances of graphene-based ECs.