The capacitive performances of carbon obtained from the electrolysis of CO2 in molten carbonates: effects of electrolysis voltage and temperature

Abstract The electrochemical reduction of CO2 to capacitive carbon in molten Li2CO3–Na2CO3–K2CO3 is an effective strategy for capturing and utilizing CO2. This paper reports the effects of the cell voltages and operating temperatures (450–650°C) of the molten salt electrolysis on the capacitive performance of electrolytic carbon. The electrolytic carbon delivers excellent specific capacitance when the cell voltage is 4.5 V and the temperature of molten salt is 450°C. The carbon obtained at 450°C and under 4.5 V delivers a specific capacitance of 550 F g−1 at 0.2 A g−1 in 1 M aqueous H2SO4, and the capacity retention rate is 73% after 10000 cycles. The specific capacitance of the electrolytic carbon increases as the electrolysis temperature decreases, and the optimal cell voltage is 4.5 V.