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

Min Kyu Song, Shuang Cheng, Haiyan Chen, Wentao Qin, Kyung Wan Nam, Shucheng Xu, Xiao Qing Yang, Angelo Bongiorno, Jangsoo Lee, Jianming Bai, Trevor A. Tyson, Jaephil Cho, Meilin Liu

Research output: Contribution to journalArticlepeer-review

202 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)3483-3490
Number of pages8
JournalNano Letters
Volume12
Issue number7
DOIs
StatePublished - Jul 11 2012

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Keywords

  • Energy storage
  • electrochemical capacitors
  • enhanced pseudocapacitance
  • in situ X-ray absorption spectroscopy
  • mixed-valent compounds

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