(361a) Holey Graphene for Electrochemical Energy Storage

Graphene, owing to its large specific surface area (SSA) and excellent electronic conductivity has been a focus of research as an electrode material in electrochemical capacitors (EC). However, van der Wall’s attraction between the individual graphene sheets results in stacking of sheets while fabricating electrodes. This phenomenon decreases the SSA and hence the performance of EC deteriorates. Another challenge is bulk manufacturing of graphene via a cheap process. These challenges can be resolved by using reduced graphene oxide (RGO), which is structurally similar to graphene with few oxygen functional groups and defects. Here, we present a simple solution based process to manufacture holey graphene from graphene oxide (GO) via microwave (MW) radiations. GO aqueous dispersion prepared by modified Hummer’s method can be converted to RGO via thermal, chemical or photochemical methods. Then, RGO in presence of hydrogen peroxide is irradiated with microwaves. It is demonstrated that OH radical are formed by microwave irradiation of H₂O₂, which can facilitate bulk synthesis of holey graphene. OH radicals produced attack both defective sites and sp² hybridized carbon within RGO. Oxidative chemical etching removes RGO-carbons to locally produce holes. This holey graphene is characterized using TEM, XPS, BET, Raman & FTIR.

Further, 3D holey graphene frameworks are prepared by using holey graphene as precursor material and is characterized using electrochemical measurements to understand relationships between 3D holey graphene framework and fundamental electrochemical (resistances, kinetics) and diffusive transport. The fundamental knowledge gained from this study can also be applied in the fields of batteries, hydrogen storage and catalysis.