Nano “Koosh Balls” of Mesoporous MnO2: Improved Supercapacitor Performance through Superior Ion Transport

Qysar Maqbool, Chanderpratap Singh, Priyajit Jash, Amit Paul, Aasheesh Srivastava

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Manganese dioxide nanomaterials with “Koosh-ball”-like morphology (MnO2-KBs) as well as worm-like nanotubes (MnO2-NWs) are obtained by employing Tween 20 as the reducing and structure-directing agent, and KMnO4 as a MnO2 precursor. Whereas the MnO2-KBs are interconnected through tubular extensions, the MnO2-NWs are largely disconnected. Both MnO2-KBs and MnO2-NWs have large BET surface areas (>200 m2 g−1), and are thermally robust up to 300 °C. Electrochemical studies reveal that the highest specific capacitance (Csp) obtained for MnO2-KBs (272 F g−1) is significantly higher than that of MnO2-NWs (129 F g−1). The Csp values correlate well with the electroactive surface areas of the materials: MnO2-KBs have a significantly higher electrolyte-accessible surface area. Electrochemical impedance spectroscopy (EIS) reveals a higher electron-transfer rate at the electrode/electrolyte interface for MnO2-KBs than for MnO2-NWs. The multiple tubular interconnections between individual MnO2-KBs allow improved ion penetration and act as conduits for their propagation, shortening the diffusion distances of the ions from external electrolytes to the interior of the MnO2 framework. Thus, this work exemplifies the importance of interconnections for enhancing the electrochemical performance of nanomaterials employed for energy storage.

Original languageEnglish
Pages (from-to)4216-4226
Number of pages11
JournalChemistry - A European Journal
Issue number17
StatePublished - 23 Mar 2017
Externally publishedYes


  • electrochemistry
  • interconnected MnO
  • ion transport
  • nanostructures
  • supercapacitors

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry


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