ISSN : 1225-0112(Print)
ISSN : 2288-4505(Online)
ISSN : 2288-4505(Online)
Research Papers : Preparation of Graphite Oxide and its Electrochemical Double Layer Capacitor`s Performances using Non-Aqueous Electrolyte (TEABF4 & TEMABF4)
Abstract
The oxidation treatment of needle cokes with 70 wt% of nitric acid and sodium chlorate (NaClO3) was attempted to achieve
an electrochemically active material with a large capacitance. The structure of needle cokes was changed to graphite oxide
after oxidation treatment of needle cokes with acidic solution having the composition ratio, NaClO3/needle cokes, of 7.5, and
the inter-layer distance of the oxidized needle cokes was extended to 6.9 Å with increasing oxygen content. On the other
hand, the electrochemical performance of oxidized needle cokes as a polarized electrode for an Electric Double Layer
Capacitor (EDLC) was examined with an electrolyte of 1.2 M TEABF4 (tetraethylammonium tetrafluoroborate) and TEMABF4
(triethylmethylammonium tetrafluoroborate) in acetonitrile. The capacitor cell using 1.2 M TEMABF4/acetonitrile has exhibited
smaller electric resistance of 0.05 Ω, and larger capacitance per weight and volume of 32.0 F/g and 25.5 F/mL at the twoelectrode
system in the potential range 0∼2.5 V than that of the capacitor cell using TEABF4. The observed electrochemical
performance was discussed with the correlation between the inter-layer distance in graphite oxide structure and the anionic
size of electrolyte.
an electrochemically active material with a large capacitance. The structure of needle cokes was changed to graphite oxide
after oxidation treatment of needle cokes with acidic solution having the composition ratio, NaClO3/needle cokes, of 7.5, and
the inter-layer distance of the oxidized needle cokes was extended to 6.9 Å with increasing oxygen content. On the other
hand, the electrochemical performance of oxidized needle cokes as a polarized electrode for an Electric Double Layer
Capacitor (EDLC) was examined with an electrolyte of 1.2 M TEABF4 (tetraethylammonium tetrafluoroborate) and TEMABF4
(triethylmethylammonium tetrafluoroborate) in acetonitrile. The capacitor cell using 1.2 M TEMABF4/acetonitrile has exhibited
smaller electric resistance of 0.05 Ω, and larger capacitance per weight and volume of 32.0 F/g and 25.5 F/mL at the twoelectrode
system in the potential range 0∼2.5 V than that of the capacitor cell using TEABF4. The observed electrochemical
performance was discussed with the correlation between the inter-layer distance in graphite oxide structure and the anionic
size of electrolyte.
연구논문 : 산화흑연의 제조 및 전해질(TEABF4 & TEMABF4)에 따른 전기이중층 커패시터의 특성
초록
전기화학적으로 용량이 큰 활물질을 얻기 위한 수단으로 니들 코크스를 NaClO3과 70 wt%의 HNO3으로 구성된 수용액을 이용하여 산화처리를 하였다. NaClO3/니들 코크스의 질량비가 7.5배인 수용액에서 산화 처리한 결과, 니들 코크스는 산화흑연 구조로 상변이가 일어나고, 또한 산소의 함유량의 증가와 함께 층간거리는 6.9 Å으로 확대되었다. 한편, 산화 니들 코크스의 전기이중층 커패시터용 분극 전극으로서의 전기화학적 특성은 acetonitrile의 용매에 각각 1.2 M의 TEABF4(tetraethylammonium tetrafluoroborate)와 TEMABF4 (triethylmethylammonium tetrafluoroborate)의 전해질이 함유된 유기용액을 각각 사용하여 조사하였다. 1.2 M TEMABF4/acetonitrile의 전해액을 사용한 커패시터 셀은 1.2 M TEABF4/acetonitrile의 전해 액을 사용한 커패시터 셀에 비해 전극저항은 0.05 Ω로 낮았고, 2 전극 기준으로 0∼2.5 V에서 측정한 용량 및 부피 당
용량은 32.0 F/g와 25.5 F/mL으로 높은 수치를 나타내었다. 이러한 전기화학적 거동을 천연흑연 구조에서의 층간 거리와 전해질의 양이온 크기와의 상관관계로 논의하였다.
용량은 32.0 F/g와 25.5 F/mL으로 높은 수치를 나타내었다. 이러한 전기화학적 거동을 천연흑연 구조에서의 층간 거리와 전해질의 양이온 크기와의 상관관계로 논의하였다.