Fabrication of surface-modified graphitic carbon materials and their electrical applications

Abstract

Because of their excellent electrical and mechanical properties, carbon materials have attracted scientific attention as essential parts for electrical applications, such as strain sensor, and battery electrode. Hence, the physical and chemical modifications of carbon surface have been investigated for enhancing the electrical performance. In this dissertation, surface characteristics of carbon, including interactions, defects, and doping on surface, are utilized. The surface is modified by three fabrication methods

solution process, etching process using redox reactions, and carbonization process to fabricate the surface morphology and chemistry with high performance. First, new types of graphene strains sensors are fabricated by a layer-by-layer assembly that uses surface interactions among carbon and polymeric materials. The three types of strain sensors, based on stretchable yarns, show high stretchability and can monitor diverse human motions. Second, a novel electrode architecture with highly porous and graphenated morphology is demonstrated by using NiO/Ni redox reactions. The structure with defects can accommodate a large number of catalytic oxygen functional group, leading to improved electrochemical performance. In the last chapter, nitrogen-doped graphite felt electrode for $VO^{2+}$/$VO_2^+$ redox reaction is fabricated by carbonization process of metal-organic framework. This method can produce porous structure with abundant nitrogen, which enhances electrochemical activity and reversibility for reaction.