A novel pseudocapacitance mechanism of elm seed-like mesoporous MoO3−x nanosheets as electrodes for supercapacitors

Abstract

Pseudocapacitance is induced by surface or near surface redox, ion intercalation or underpotential deposition processes. A given electrochemically active material usually has only one of the above mechanisms. In this study, we synthesized elm seed-like mesoporous MoO_3−x nanosheets, which possess both redox and intercalation faradic mechanisms. This novel pseudocapacitance mechanism causes a high capacitance of 1480 F g⁻¹ at 5 A g⁻¹ and outstanding cycling performance where the capacitance does not decay but increases slightly up to 10 000 cycles at a scan rate of 100 mV s⁻¹. Here, we clarified that the tunnel structure of MoO_3−x and its special electrochemical kinetics towards H⁺ generate this mechanism. This faradic mechanism could achieve a higher degree of utilization of the active-sites thus resulting in excellent electrochemical performance.