Nitrogen-Doped Seamless Activated Carbon Electrode with Excellent Durability for Electric Double Layer Capacitor

Abstract

The electric double layer capacitor (EDLC) using a seamless activated carbon electrode shows an excellent durability against high voltage charging compared to the conventional activated carbon composite electrode. In this study, the authors focused on nitrogen-doping as a surface modification to further improve the electrochemical durability of the seamless electrode. The EDLC using the nitrogen-doped seamless activated carbon electrode achieved the volumetric capacitance of 18 F cm−3 (based on the galvanostatic method, 80 mA g−1, 0–2.5 V, 40 °C) and the capacitance retention of 83% after the float durability test (3.5 V, 70 °C, 100 h) using a typical propylene carbonate electrolyte. The volumetric capacitance is comparable to that (14 F cm−3) of the conventional activated carbon, such as YP50F, and the retention is much higher than that (76%) of the pristine seamless activated carbon. The authors concluded that the extremely excellent durability of the nitrogen-doped seamless activated carbon electrode is due to (i) the stable electric network arising from the binder-less monolithic structure and (ii) nitrogen surface functionalities that suppresses micropore blocking and internal resistance change caused by electrochemical decomposition deposits.