화학공학소재연구정보센터
HWAHAK KONGHAK, Vol.41, No.6, 788-794, December, 2003
폴리피롤이 함유된 PVdF-HFP/PVP를 이용한 Supercapacitor용 복합전극의 전기화학적 특성
Electrochemical Characteristics of Composite Electrodes with Polypyrrole for Supercapacitor with PVdF-HFP/PVP
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초록
전도성 고분자인 폴리피롤을 5-8 wt% 첨가한 활성탄 (BP-20 및 YP-17)에 Poly (vynylidenefluoride-co-hexafluoropropylene) (PVdF-HFP)/polyvinylpyrrolidone(PVP)의 혼합결합제를 n-methyl-2-pyrrolidinone(NMP)에 용해시켜 복합전극을 제조하였다. 단위셀의 충·방전 특성, 비정전용량, AC-ESR, 에너지밀도, CV 및 impedance 특성 등의 전기화학적 특성을 측정하였다. 혼합결합제를 5 wt%로 고정하였을 때 전극의 유연성, 높은 기계적 강도 및 우수한 전기화학적 특성을 갖는 전극을 제조하기 위하여 폴리피롤의 무게함량이 8 wt% 이내로 첨가하는 것이 적당하였다. 특히, BP-20의 전극에 첨가된 폴리피롤의 무게함량이 7 wt%일 때 전극의 비정전용량 34.77 F/g, AC-ESR 0.65 Ω, 에너지밀도 8.16 Wh/kg 및 동력밀도 1,830 W/kg으로 상용화된 제품보다 우수하였고 Ragone plot 상에서 볼 때 전기자동차에 적용할 가능성을 볼 수 있었다.
Composite electrodes were fabricated based on activated carbons such as YP-17 and BP-20, and conducting polymer of polypyrrole (pPy) prepared by chemical polymerization in our laboratory. Mixed binders of Poly (vinylidene-fluorideco-hexafluoropropylene) (PVdF-HFP) and polyvinylpyrrolidone (PVP) in n-methyl- 2-pyrrolidinone (NMP) were added to the activated carbons. Electrochemical characteristics of unit cells such as charge-discharge, specific capacitance, ESR, specific energy, cyclic voltammetry (CV) and impedance were measured. It was noted that a pPy content within 8 wt. % greatly increased the electrochemical characteristics, mechanical strength and flexibility with the fixed 5 wt. % of mixed binder. Especially, the BP-20 electrode with 7 wt% of pPy exhibited better electrochemical characteristics than commercialized products, with 34.77 F/g of specific capacitance, 0.65 Ω of AC-ESR, 8.16 Wh/kg of specific energy, and specific power of 1,830 W/kg. Power outputs were compatible with electric vehicle applications, in due consideration of Ragone relations.
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