Effect of Surface Characteristics of Reduced Graphene Oxide on the Performance of Pseudocapacitor

Abstract

It is well known that reduced graphene oxide (rGO) has been intensely researched for applications in supercapacitors and rGO/metal oxide composite have also been spotlighted for its pseudocapacitive effects. Though metal oxides have high specific capacitance and electrochemical stability, they also show poor rate capability and low accessible surface areas. In order to overcome these problems, many fabrication methods of the composite has been suggested, such as, microwave assisted reflux methods by Rao et al., and electrochemical deposition method by Cao et al., which showed high specific capacitance values. However, other than just fabricating a composite and showing that it has a high value as listed above, no research has been done on verifying which kind of rGO plays the ideal role as a substrate for metal oxide composites in terms of rGOs surface characteristics, chemical properties, and preparation methods. Therefore, it came to our interest, that in order to fabricate rGO/metal oxide supercapacitor with high electrochemical performance, not only do we need to research on the composite fabrication methods, but also need to provide a guideline of how to prepare rGO substrate of different size, and functional groups. In this research, we analyzed the electrochemical characteristics of the different rGO/Co3O4 composites prepared by controlling rGOs surface characteristics and its relationship between the performance of the pseudocapacitor, providing a guideline for the ideal fabrication of rGO/metal oxide composite for psuedocapacitor. This way, further researches using rGO as electrode material for pseudocapacitors can, from now on, take our research into account for improved electrochemical performances.