Comparison of reducing agent for reduced graphene oxide as cathode for zinc-ion hybrid capacitors

Abstract

Abstract The comparative study of using the different reduced graphene oxide sources, obtained from thiourea and 1-ascorbic acid as reducing agent, for zinc cathode capacitors is investigated. The chemical structure and the surface morphology of both reduced graphene oxide samples are examined by infrared spectrum and scanning electron microscopy, respectively. Serving as cathode for zinc-ion hybrid capacitors, the as-prepared reduced graphene from 1-ascorbic acid reveals the better the specific discharge capacity (41.50 mAh g -1 ) than that of the obtained from thiourea (40.78 mAh g -1 ). The cycle stability of zinc-ion hybrid capacitors coin cell in 2M ZnSO 4 electrolyte is examined by multi-cycles of GCD at 0.1 A g -1 , demonstrating that rGO obtained from 1-ascorbic acid can endow the retention up to 72.8% after 200 cycles, while rGO obtained from thiourea is remained at 63.1%.