High-performance aqueous asymmetric electrochemical capacitors based on graphene oxide/cobalt(ii)-tetrapyrazinoporphyrazine hybrids

摘要

A novel asymmetric electrochemical capacitor (AEC) with high energy and power densities has beendeveloped using a graphene oxide/cobalt(II)tetrapyrazinoporphyrazine composite (GO/CoTPyzPz) as thepositive electrode and graphene oxide/carbon black (GO/CB) as the negative electrode in a neutralaqueous Na2SO4 electrolyte. The excellent specific capacitance, energy and power densities ( 500 F g 1,44 W h kg 1 and 31 kW kg 1) coupled with long cycle life, excellent short response time, and lowequivalent series resistance clearly indicate that this new material has great potential for thedevelopment of low-cost and ‘green’ aqueous AECs that operate at high energy and power densities.Interestingly, the energy density of the GO/CoTPyzPz//GOCB based AEC falls within the range usuallyobserved for nickel metal hydride (NiMH) batteries (30–100 W h kg 1), but more importantly, showsbetter power performance than NiMH batteries (0.25–1 kW kg 1) widely used in hybrid vehicles such asToyota Prius and Honda Insight.