A two-volt aqueous supercapacitor from porous dehalogenated carbon - Carbon4Energy

Aqueous supercapacitors were among the most promising techniques for clean and renewable energy storage yet limited by their low specific energy arisen from water splitting issue. Herein, water splitting-inactive electrode materials of mesoporous carbon were fabricated through the dehalogenation of polyvinylidene fluoride (PVDF) by sodium ethoxide (EtONa). The as-generated EtOH and NaF have been demonstrated to facilitate the formation of hierarchical porous carbon based on the bubble and templating effects. Due to the full dehalogenation, the resulted carbon materials acquired high carbon contents where the unfavorable alien dopants are absent. The resulted porous dehalogenated carbon materials were applied as electrode materials for the aqueous supercapacitor neutral electrolyte. The as-proposed significantly suppressed water-splitting activity has been addressed in the electrochemical system. The open circuit voltage (OCV) could be therefore safely expanded to 2.0 V. Over 94.0 % of capacitance is also maintained after cycling 5,000 times at 5.0 A/g. Our strategy that utilizes water-splitting inactive electrode materials to expand working window of aqueous supercapacitor may enlighten the design of materials for aqueous supercapacitor with higher OCV over 2.0 V.