Activated Carbon Derived from Wood Biochar and Its Application in Supercapacitors

The work described in this paper was performed to evaluate a potential application of the value-added biochar-derived activated carbon as an electrode material for supercapacitor manufacturing and to measure the electrochemical characteristics of fabricated single and stack coin supercapacitors. Physico-chemical characterization of raw material and economically-attractive physical activation (CO2 and CO2 saturated with 3% H2O) were used to produce activated carbon with suitable parameters. Optimization of activation conditions (temperature, duration, gaseous environment) allowed production of activated carbon with a high surface area (BET) up to 1500 m(2)/g and iodine number up to 1200 mg/g. The most promising activated carbon was used for supercapacitor electrode fabrication. A dip-coating method was developed and utilized to prepare the large 10 x 10 cm electrode sheets based on Ni-foam as a support. For electrochemical characterization a batch of single coin cells (based on commercially available 2032 design/size factor) utilizing inexpensive aqueous electrolyte K/LiOH 5 M was fabricated and tested by a number of industry-accepted methods for the electrochemical performance evaluation. Based on a single cell design a stack with operating voltage of 4.5 V was assembled and evaluated.