Self-templated construction of sargassum- based activated carbon and its electrochemical properties

Orthogonal experiments have been carried out to study the optimal process conditions for the preparation of sargassum-based activated carbon with different impregnation ratios， impregnation times， activation temperatures， and activation times based on the self-templated “egg-box” structure using sargassum as the raw material and ZnCl2 as the activator. The characterization of N2 adsorption， SEM， and XRD investigate the pore structure properties， surface morphology， and crystal structure of the activated carbon. The electrochemical properties of sargassum-based activated carbon are tested. The optimum process conditions for preparing high specific capacitance activated carbon are analyzed by orthogonal experimental method and obtained as follows： impregnation ratio is 3， impregnation time is 2 h， activation temperature is 700 ℃， and activation time is 2 h. Under nine sets of experimental conditions， the prepared activated carbon SAC7 exhibits the best electrochemical performance， the specific capacitance of activated carbon SAC7 is as high as 136.4 F/g when the current density is 0.5 A/g， and its specific capacitance is as high as 92.0 F/g when the current density is 5 A/g， which shows a superior specific capacitance and rate performance. After 10000 cycles of charging and discharging， the SAC7 still has a capacitance retention rate as high as 99.41%， with excellent cycling stability.