High specific surface area activated carbon derived from ZIF-8 for supercapacitor

Compared to strong alkali activating agents (KOH, NaOH), transition metal salts as activating agents could neither corrode equipment nor pose a danger to operators. However, the surface area of the carbon materials carbonized by transition metal salts is lower than that activated by alkali activating agents. And the specific surface area of the carbon materials is related with electrochemical performance of supercapacitor. Thus, transition different metal salts are as the activating agents to activate the ZIF-8 to obtain the high specific surface area carbon. In addition, the effect of the amount of Zn(NO₃)₂ impregnation on the the final specific surface area and the electrochemical properties of these activated carbons in a 6 M KOH electrolyte are investigated in depth. The large specific surface area activated carbon have been obtained after calcination under 1000ºC with using ZIF-8 as the precursor and transition metal salts as the activating agents. The Zn(NO₃)₂ of lower boiling point and easy reduction as the activating agent, the specific surface area can reach up to 1700 m²·g^-1. And the specific capacitance is up to 197.5 F·g^-1 and energy density is 6.9 Wh·kg^-1 at 125 W·kg^-1 in 6 KOH electrolyte.