Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Supercapacitive Properties of Carbon-Nano Fiber/MnO2 Composite Electrode

나노탄소섬유/MnO2 복합전극의 초고용량 캐폐시터 특성

  • Lee, Byung Jun (Division of Applied Chemistry and Biotechnology, Hanbat National University) ;
  • Yoon, Yu Il (Division of Applied Chemistry and Biotechnology, Hanbat National University) ;
  • Ko, Jang Myoun (Division of Applied Chemistry and Biotechnology, Hanbat National University)
  • 이병준 (한밭대학교 응용화학생명공학부) ;
  • 윤여일 (한밭대학교 응용화학생명공학부) ;
  • 고장면 (한밭대학교 응용화학생명공학부)
  • Received : 2007.10.19
  • Accepted : 2007.10.20
  • Published : 2008.02.28
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Abstract

In order to improve the specific capacitance of amorphous hydrous manganese oxide ($MnO_2$) for supercapacitors, it is made into composites with vapour-grown carbon nanofibers (VGCF) having the VGCF ratio as 40 wt% in the composites. The electrochemical properties of these composites are investigated in 1.0 M $Na_2SO_4$ by cyclic voltammetry (CV), impedance measurements and chronopotentiometric charger/discharger. The composite with 40 wt% VGCF shows the superior electrochemical performance, whose specific capacitance (based on the mass of $MnO_2$, $0.8mg/cm^2$) is 380 F/g at 20 mV/s and 230 F/g at 500 mV/s. Also, the cycle-life testing of this electrode carried out for 3,000 charge/discharge cycles at $2.0mA/cm^2$ shows 97% capacitance retention.

비정형 $MnO_2$의 초고용량 캐폐시턴스 특성을 향상시키기 위하여 망간산화물을 높은 전기전도를 갖는 나노탄소섬유(vapour-grown carbon nanofibers, VGCF)와 복합화하여 나노탄소섬유/망간 산화물(VGCF(40 wt%)/$MnO_2$) 복합 전극을 제조하여 cyclic voltammetry(CV), impedance spectroscopy 및 chronopotentiometric charge/discharge 기법을 사용하여 1.0M $Na_2SO_4$ 전해질에서 초고용량 캐폐시터 특성을 조사하였다. 40 wt% VGCF를 포함한 복합전극에서 $0.8mg/cm^2$ 망간산화물을 로딩한 $VGCF/MnO_2$ 복합전극은 주사속도 20 mV/s에서는 380 F/g, 500 mV/s에서는 230 F/g의 비용량 값을 나타냈다. 또한, $2.0mA/cm^2$의 일정전류로 충방전 실험을 수행한 결과 3,000회에서 97%의 초기용량을 유지하였다.

Keywords

References

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