Abstract
In this study, we propose a simple way to improve thermal stability of solid-state supercapacitors (SCs) by adding carbon black (CB) into reduced graphene oxide (rGO) electrodes. The CB used as a heat-resistant additive contributes to stable operation of the rGO-CB SC even after 1000 charge/discharge cycles at 90 °C. In the case of the rGO SC without CB, it fails after the 166th cycles at 90 °C. Compared with the rGO SC, the rGO-CB SC exhibits the decrease in internal resistance from 42 to 18 Ω and the increase in specific capacitance from 115 to 160 F/g. Moreover, the rGO-CB SC shows a smaller variation in specific capacitance (12%) than that of rGO SC (30%) as the temperature increases from 30 to 90 °C. The observation reveals that the addition of CB being a heat-resistant additive helps improve performance of thermal stable SCs.