Activated carbons effectively purified by post-heat treatment under vacuum conditions

Junam Kim, Hoai Van Hoai, Gyung Jin Bahk, Kyungwon Kwak, Kyung Koo Lee

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The effect of heat treatment and vacuum conditions on the textural properties and electrochemical performance of commercially available activated carbons (ACs) was investigated. The AC after post-heat treatment was characterized by nitrogen adsorption–desorption, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy measurements. The ACs treated under vacuum conditions exhibit a higher specific surface area and micropore surface area than those treated under nitrogen atmospheric pressure without significantly affecting the graphite structure of the AC. Under 800 °C temperature and vacuum conditions (AC-V800), the AC with the highest Brunauer–Emmett–Teller surface area of 1951.9 m2 g−1 (16.4% improvement relative to that of the original AC (1677.2 m2 g−1)) was obtained. This is attributed to the removal of oxygen-containing functional groups and volatile matters in the carbon by thermal treatment under vacuum conditions. Consequently, the electric double-layer capacitor using ACs treated under vacuum conditions (1 kPa) at 800 °C (AC-V800) shows considerably improved electrochemical performance in terms of higher specific capacitance and better cycling stability at a high working voltage (3.1 V), compared to the nitrogen-treated and commercial ACs.

Original languageEnglish
Pages (from-to)973-984
Number of pages12
JournalCarbon Letters
Issue number5
Publication statusPublished - 2021 Oct


  • Activated carbon
  • Electric double-layer capacitor
  • Oxygen-containing functional groups
  • Specific surface area
  • Vacuum heat treatment

ASJC Scopus subject areas

  • Ceramics and Composites
  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Process Chemistry and Technology
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry


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