As an activation procedure, in this study, the oxidation treatment of needle cokes with a dilute nitric acid and sodium chlorate (NaClO3), combined with heat treatment, was attempted. The structures of acid-treated and pyrolyzed coke were examined with XRD, FESEM, elemental analyzer, BET, and Raman spectroscopy. The behavior of double layer capacitance was investigated with the analysis of charge and discharge. The structure of needle coke treated with acid was revealed to a single phase of (001) diffraction peak after 24 h. On the other hand, thecoke oxidized by heat treatment was reduced to a graphite structure of (002) at 300℃. The distorted graphene layer structure, derived from the process of oxidation and reduction of the inter-layer, makes the pores by the electric field activation at the first charge, and generates the double layer capacitance from the second charge. The cell using pyrolyzed coke with 24 h acid treatment and 300 ℃ heat treatment exhibited the maximum capacitance per weight and volume of 33 F/g and 30 F/mL at the two-electrode system in the potential range of 0∼2.5 V.

니들 코크스의 활성화 방법으로서 기존의 방법과는 다른 HNO3와 NaClO3 혼합용액에서의 산처리와 300℃ 열처리 방법을 이용하였다. 산처리 코크스와 열분해 코크스의 미세구조는 XRD, FESEM, element analysis, BET, Raman spectroscopy를 이용하였으며, 전기이중층 거동은 충방전 분석을 행하였다. 니들 코크스는 산처리 시간에 따라 산소의 중량 %의 증가와 함께 (001) 구조로 상변화가 일어나고, 300℃ 열처리에서 흑연구조인 (002) 구조로 환원한다. 이들 산처리-상분해 과정에서 층간에 유기된 층간 구조결함은 first 충전에서 전계 활성화에 의해 pore를 생성하고 second 충전에서는 전기이중층 용량을 발생시킨다. 24 h 산처리-300 ℃ 열처리한 열분해 코크스의 2.5V까지의 2 전극 기준에서 구한 활물질 중량 당 용량과 전극 부피 당 용량는 각각 33F/g과 30F/mL를 나타내었다.