Solution-plasma treatment of activated carbon from shochu distillery waste for electrochemical capacitors

Daisuke Tashima, Masaki Hirano, Satoshi Kitazaki, Takuya Eguchi, Seiji Kumagai

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6 Citations (Scopus)


In this study, activated carbon was prepared from shochu (Japanese distilled liquor) waste for use as an electrode material in electric double-layer capacitors (EDLCs). To increase the capacitance and energy density, the activated carbon was subjected to a solution-plasma surface treatment using a DC power source. The plasma was generated in the gas phase of the electrolyte. The optimal treatment conditions were determined by varying the applied voltage, treatment time, and electrolyte. After treatment at 240 V in potassium hydroxide (KOH) solution, the capacitance of the EDLC increased by 11.7%, while its internal resistance reduced by 31.8%. Infrared spectrometry was performed on the surface-treated activated carbon samples. The spectra confirmed the presence of oxygen-containing functional groups, such as –COO groups and C[dbnd]O bonds. Thus, the observed increase in the capacitance was attributed to an increase in the surface wettability of the material, along with the appearance of pseudocapacitance.

Original languageEnglish
Article number123523
JournalMaterials Chemistry and Physics
Publication statusPublished - 1 Nov 2020
Externally publishedYes


  • Activated carbon
  • Electric double-layer capacitor
  • Solution-plasma treatment


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