Effective Reduction of Graphene Oxide for Energy-storage Devices

Graphene is a two-dimensional allotrope of carbon with the honeycomb structure, and it has the precious properties such as high thermal conductivity (∼5000 Wm−1K−1) and skyscraping electron mobility (200,000 cm2V−1s−1) [1]. Moreover, graphene can be made from graphite which is cheap and has a large reserve in nature so that it has become the “rising star” for high technology research work [2]. Among many routes to produce graphene, the chemical method through graphene oxide (GO) is considered as an easy and economical way [3]. GO, however, is an insulator unfortunately so it is needed to reduce oxygen functional groups for recovering the graphene structure of high conductivity. Chemical or thermal reduction processes of GO have been investigated [4–6]. Each pathway has certain advantages and disadvantages, resulting in different degrees of regeneration of the graphene structure. Our recent research has been investigated the grain size effect on the electrochemical performance of the chemically reduced GO [7], finding that the smallest grain size, 5 μm, provided the best electrochemical performance due to better reduction compared to the other chemically reduced GO