CARBONLETT, vol. 25, no. 1, pp.14-24, 2018

DOI: http://dx.doi.org/ DOI:10.5714/CL.

Preparation and capacitance properties of graphene based composite electrodes containing various inorganic metal oxides

Jeonghyun Kim, Sang Chul Byun, Sungwook Chung, Seok Kim

Affiliation: Pusan National University

Abstract: Electrochemical properties and performance of composites performed by incorporating metal oxide or metal hydroxide on carbon materials based on graphene and carbon nanotube (CNT) were analyzed. From the surface analysis by field emission scanning electron microscopy and field emission transmission electron microscopy, it was confirmed that graphene, CNT and metal materials are well dispersed in the ternary composites. In addition, structural and elemental analyses of the composite were conducted. The electrochemical characteristics of the ternary composites were analyzed by cyclic voltammetry, galvanostatic charge-discharge tests, and electrochemical impedance spectroscopy in 6 M KOH, or 1 M Na2SO4 electrolyte solution. The highest specific capacitance was 1622 F g-1 obtained for NiCo-containing graphene with NiCo ratio of 2 to 1 (GNiCo 2:1) and the GNS/single-walled carbon nanotubes/Ni(OH)2 (20 wt%) composite had the maximum specific capacitance of 1149 F g-1. The specific capacitance and rate-capability of the CNT/MnO2/reduced graphene oxide (RGO) composites were improved as compared to the MnO2/RGO composites without CNTs. The MnO2/RGO composite containing 20 wt% CNT with reference to RGO exhibited the best specific capacitance of 208.9 F g-1 at a current density of 0.5 A g-1 and 77.2% capacitance retention at a current density of 10 A g-1.

Keyword: inorganic oxide, reduced graphene oxide, composite electrodes, capacitance, supercapacitor, metal hydroxide, carbon nanotube