A High‐Performance Symmetric Supercapacitor from Porous Activated Carbon under Compression

Abstract

The realization of biomass‐derived supercapacitors of high performance is of practical importance for the manufacturing of supercapacitors from green and renewable sources. Herein, the feasibility of constructing high‐performance supercapacitors from potato‐derived activated carbon (AC) is demonstrated. The potato‐derived AC is produced from potato mash through hydrothermal treatment and high‐temperature activation with KOH as agent. The supercapacitors with aqueous electrolyte of 6 m KOH and a mass loading of 5 mg per electrode achieve a specific gravimetric capacitance of 333.7 F g−1 per electrode and a specific energy of 11.75 W h g−1 at a specific power of 197.6 W kg−1 at a current density of 0.4 A g−1 under a nominal compressive stress of 7.96 MPa. The supercapacitors with a mass loading of 10 mg per electrode achieve the maximum specific gravimetric capacitance of 340.6 F g−1 and a specific energy of 11.75 W h g−1 at a specific power of 194.2 W kg−1 at a current density of 0.4 A g−1 under a nominal compressive stress of 7.96 MPa. Increasing the compaction of electrode materials under compressive stress has the potential to increase the electrochemical performance of supercapacitors.