Arrays of mesoporous manganese dioxide, mp-MnO2, nanowires were electrodeposited on glass using the lithographically patterned nanowire electrodeposition (LPNE) method. TEM revealed the presence within these nanowires of a network of 3-5 nm diameter fibrils that were X-ray and electron amorphous, consistent with the measured porosity values. mp-MnO2 nanowires were rectangular in cross-section with adjustable height, ranging from 21 to 63 nm, and adjustable width ranging from 200 to 600 nm. Arrays of 20 nm - 400 nm mp-MnO2 nanowires were characterized by a specific capacitance, Csp, of 923�24 F/g at 5 mV/s and 484�15 F/g at 100 mV/s. These Csp values reflected true hybrid electrical energy storage with significant contributions from double-layer capacitance and noninsertion pseudocapacitance (38% for 20 nm X 400 nm nanowires at 5 mV/s) coupled with a Faradaic insertion capacity (62%). These two contributions to the total Csp were deconvoluted as a function of the potential scan rate.

Mesoporous manganese oxide nanowires for high capacity, high rate, hybrid electrical energy storage

243rd National Meeting (2012)

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