Influence of Activated Condition on the Structure of Diatomite-templated Carbons and Their Electrochemical Properties as Supercapacitors

The diatomite-templated carbons were prepared using diatomite as template and furfuryl alcohol as carbon resource, and were further activated using potassium hydroxide as an activating agent. The structure, pore parameters, and electrochemical capacity of diatomite-templated carbons after activation were investigated to evaluate the influence of activated condition. The results showed active carbons contained a proportion of disordered materials in the form of amorphous carbon and ordering decreased at higher activation temperatures, however, it had little relationship to KOH/carbon mass ratio. Pore parameters, such as the specific surface area and pore volume, as well as the micropore volume, showed a growing trend with the increase of activation temperature and KOH/carbon mass ratio but micro porosity showed an opposite trend. The specific capacitance of all samples were ranging from 51.5 to 98.1 F g−1 at current density of 1 A g−1 and capacitance retention could maintain at more than 70% at current density of 20 A g−1, indicating they had good electrochemical properties. Moreover, electrochemical property became better as activation temperature and KOH/carbon mass ratio decreased.