Pseudocapacitive behavior of manganese oxide in lithium-ion-doped butylmethylpyrrolidinium-dicyanamide ionic liquid investigated using in situ X-ray absorption spectroscopy

Ming Tsung Lee, Yun Shan Li, I. Wen Sun, Jeng-Kuei Chang*

*Corresponding author for this work

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Ideal pseudocapacitive behavior of α-MnO2 electrodes over a potential range of 3 V is found in lithium bis(trifluoromethylsulfonyl)imide (LiTFSI)-doped butylmethylpyrrolidinium-dicyanamide (BMP-DCA) ionic liquid (IL), which is non-flammable and has a decomposition temperature of as high as ∼300 C. Accordingly, this electrolyte is promising for high-energy, high-power, and high-safety supercapacitor applications. The addition of 0.01 M LiTFSI in the IL improves the oxide capacitance from 90 F g-1 to 120 F g-1, which is due to the incorporated Li+ ions promoting Mn valent state variation (between trivalent and tetravalent) during charge-discharge. However, excessive LiTFSI doping causes a capacitance decay due to reduced electrolyte ionic conductivity. In situ X-ray absorption spectroscopy is used to investigate the energy storage mechanism. A capacitance activation process of α-MnO2 in the Li+-doped BMP-DCA IL is found.

Original languageEnglish
Pages (from-to)269-276
Number of pages8
JournalJournal of Power Sources
Volume246
DOIs
StatePublished - 1 Jan 2014

Keywords

  • Ionic liquids
  • Lithium ion doping
  • Manganese oxide
  • Supercapacitors
  • X-ray absorption spectroscopy

Fingerprint Dive into the research topics of 'Pseudocapacitive behavior of manganese oxide in lithium-ion-doped butylmethylpyrrolidinium-dicyanamide ionic liquid investigated using in situ X-ray absorption spectroscopy'. Together they form a unique fingerprint.

  • Cite this