Anomalous pseudocapacitive behavior of a nanostructured, mixed-valent manganese oxide film for electrical energy storage

Document Type

Article

Publication Date

7-11-2012

Abstract

While pseudocapacitors represent a promising option for electrical energy storage, the performance of the existing ones must be dramatically enhanced to meet todays ever-increasing demands for many emerging applications. Here we report a nanostructured, mixed-valent manganese oxide film that exhibits anomalously high specific capacitance (∼2530 F/g of manganese oxide, measured at 0.61 A/g in a two-electrode configuration with loading of active materials ∼0.16 mg/cm2) while maintaining excellent power density and cycling life. The dramatic performance enhancement is attributed to its unique mixed-valence state with porous nanoarchitecture, which may facilitate rapid mass transport and enhance surface double-layer capacitance, while promoting facile redox reactions associated with charge storage by both Mn and O sites, as suggested by in situ X-ray absorption spectroscopy (XAS) and density functional theory calculations. The new charge storage mechanisms (in addition to redox reactions of cations) may offer critical insights to rational design of a new-generation energy storage devices. © 2012 American Chemical Society.

Identifier

84863848926 (Scopus)

Publication Title

Nano Letters

External Full Text Location

https://doi.org/10.1021/nl300984y

e-ISSN

15306992

ISSN

15306984

First Page

3483

Last Page

3490

Issue

7

Volume

12

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