Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1293040 | Journal of Power Sources | 2012 | 4 Pages |
Phase pure, nanostructured V, Mo and W nitrides and carbides were synthesized and characterized in aqueous KOH and H2SO4 electrolytes. Capacitances for most of the materials exceeded that expected for double layer charging and suggested a pseudocapacitive storage mechanism. With the exception of β-Mo2C, the materials were stable in KOH and/or H2SO4 electrolytes. Capacitances for VN in KOH and γ-Mo2N in H2SO4 were the highest and exceeded 200 F g−1. The charge-storage species were interrogated using an ion isolation method. The results provide unambiguous evidence that OH− was the principal charge storage species responsible for the pseudocapacitance demonstrated for VN in KOH while H+ was the principal species for γ-Mo2N in H2SO4.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Capacitances in excess of 200 F g−1 for phase-pure VN and γ-Mo2N in KOH and H2SO4, respectively. ► Electrolyte ion isolation experiments used to identify key contributors to charge storage. ► Ion isolation results unambiguously link OH− and H+ to pseudocapacitance for VN/KOH and Mo2N/H2SO4, respectively.