Hybrid MnO2-disordered mesoporous carbon nanocomposites: Synthesis and characterization as electrochemical pseudocapacitor electrodes

Mehul N. Patel, Xiqing Wang, Brian Wilson, Domingo A. Ferrer, Sheng Dai, Keith J. Stevenson, Keith P. Johnston

Research output: Contribution to journalArticlepeer-review

77 Citations (Scopus)

Abstract

MnO2-mesoporous carbon hybrid nanocomposites were synthesized to achieve high values of redox pseudocapacitance at scan rates of 100 mV s -1. High-resolution transmission electron microscopy (HRTEM) along with energy dispersive X-ray spectroscopy (EDX) demonstrated that ∼1 nm thick MnO2 nanodomains, resembling a conformal coating, were uniformly distributed throughout the mesoporous carbon structure. HRTEM and X-ray diffraction (XRD) showed formation of MnO2 nanocrystals with lattice planes corresponding to birnessite. The electrochemical redox pseudocapacitance of these composite materials in aqueous 1 M Na 2SO4 electrolyte containing as little as 2 wt% MnO 2 exhibited a high gravimetric MnO2 pseudocapacitance (CMnO2) of 560 F gMnO2-1. Even for 30 wt% MnO2, a high CMnO2 of 137 F gMnO2-1 was observed at 100 mV s-1. Sodium ion diffusion coefficients on the order of 10-9 to 10-10 cm2 s-1 were measured using chronoamperometry. The controlled growth and conformal coating of redox-active MnO2-mesoporous carbon composites offer the potential for achieving high power energy storage with low cost materials.

Original languageEnglish
Pages (from-to)390-398
Number of pages9
JournalJournal of Materials Chemistry
Volume20
Issue number2
DOIs
Publication statusPublished - 2010
Externally publishedYes

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