Secondary carbon skeletons constructed in porous carbon for electric double layer capacitors

Abstract

In this work, a secondary skeleton was constructed by filling the larger spaces of porous carbon derived from passion fruit peels with glucose to created more carbon surface in same volume. The combined use of KOH activation and simultaneous etching of micropores on the carbon skeleton and secondary skeleton resulted in the preparation of porous carbon (PGC1-0.5) containing a large number of micropores. PGC1-0.5 have less total pore volume (0.987 cm³ g⁻¹), but more micropore volume (0.821 cm³ g⁻¹), different with 1.171 cm³ g⁻¹, 0.668 cm³ g⁻¹ of PGC1-0, which without glucose. Symmetric supercapacitor bases on PPGC1-0.5 have an obvious improvement in specific capacity (275.6 F g⁻¹ (175 F cm⁻³), 0.1 A g⁻¹) in 6 M KOH electrolyte compared to PGC1-0 (215.2 F g⁻¹ (121.5 F cm⁻³), 0.1 A g⁻¹). Additionally, the device exhibits excellent cycling performance and retained 103% of its specific capacity after 10,000 cycles and notable reduction in transfer internal resistance in comparison to the sample without glucose. This study shows that filling space with glucose to reduce macropores is an effective method for adjusting the pore size distribution of porous carbon.