電気二重層キャパシタ用活性炭電極における熱処理時間の高電圧充電耐久性に及ぼす影響

抄録

Phenolic-resin based steam-activated carbon fiber (ACF) for electric double layer capacitors was subjected to heattreatment at 1500°C in nitrogen. The dependence of the pore structure and the capacitance retention rate after high voltage charging (3 V, 100 h, 70°C) on the heating duration was investigated using a two-electrode cell with propylene carbonate electrolyte. The micropore-shrinkage and the removal of the oxygen-containing surface functionalities of the ACF were accomplished within a short time (5 seconds) by the heat-treatment, however a longer time (1 hour) was necessary to improve the capacitance retention rate. The Raman analysis revealed that the local ordering structure changed slowly by heat-treatment at 1500°C, suggesting the sufficiently long heat-treatment essential to the improvement of the capacitance retention rate.