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

Joel N. Lekitima, Kenneth I. Ozoemena, Charl J. Jafta, Nagao Kobayashi, Yang Song, Dennis Tong, Shaowei Chen, Munetaka Oyama

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

A novel asymmetric electrochemical capacitor (AEC) with high energy and power densities has been developed using a graphene oxide/cobalt(ii) tetrapyrazinoporphyrazine composite (GO/CoTPyzPz) as the positive electrode and graphene oxide/carbon black (GO/CB) as the negative electrode in a neutral aqueous 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 low equivalent series resistance clearly indicate that this new material has great potential for the development 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 usually observed for nickel metal hydride (NiMH) batteries (30-100 W h kg-1), but more importantly, shows better power performance than NiMH batteries (0.25-1 kW kg-1) widely used in hybrid vehicles such as Toyota Prius and Honda Insight.

Original languageEnglish
Pages (from-to)2821-2826
Number of pages6
JournalJournal of Materials Chemistry A
Volume1
Issue number8
DOIs
Publication statusPublished - 2013 Feb 28

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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