Thermal Stability and Deintercalation of K-synthetic Graphite Intercalation Compounds at Elevated Temperatures

칼륨-인조 흑연 층간 화합물의 고온열적 안정성과 Deintercalation

K-SGICs(synthetic graphite intercalation compounds) were synthesized in a modified two-bulb pyrex tube. The pressure in the two-bulb tube was maintained at approximately $10^{-3}$ torr for the reaction of potassium and graphite. Deintercalation process of the K-SGlCs obtained by the modified method was heat-treated by keeping in liquid paraffin between $25^{\circ}C$ and $1400^{\circ}C$. The thermal stability and the temperature dependence of the K-SGICs were characterized using differential scanning calorimeter(DSC) analyzer. Enthalpy and entropy for K-SGIC formations were calculated by confirming the deintercalation and thermodynamic exothermic reactions depending on the various temperatures. The structure changes and thermal stability of K-SGICs during the deintercalation reaction of potassium ions and the interlayer spaces of the synthetic graphite were identified by X-ray diffraction(XRD).

변형된 two-bulb pyrex관을 사용하여 K-SGICs(인조흑연 층간화합물)를 합성하였다. 흑연과 칼륨을 반응시키기 위하여 two-bulb관내에 압력을 $10^{-3}$ torr로 유지하여 주었다. 변형된 방법에 의하여 얻어진 K-SGICs는 유동 파라핀 내에서 $25{\sim}1400^{\circ}C$ 사이에서 열처리하여 deintercalation을 시켰다. K-SGICs의 온도 의존성과 열적 안정성을 DSC 분석기에 의하여 특성화하였다. K-SGIC의 엔탈피와 엔트로피 형성은 여러 온도에 의존하는 열역학적 발열반응과 deintercalation을 확인하여 계산하였다. 칼륨이온의 deintercalation 반응이 얼어나는 동안 K-SGICs 의 구조변이와 열적 안정성을 XRD에 의하여 확인하였다.