Waste-to-energy material: Winery-waste derived heteroatoms containing graphene-like porous carbon for high-voltage supercapacitor

Recycling industrial waste to produce energy and storage materials provides the best means of addressing its environmental impact and achieving economic benefits. This study used solid industrial winery waste to prepare an innovative heteroatom containing graphene-like porous carbon (HGPC) by simple heat treatment and chemical activation using KOH. The prepared N and S containing HGPC had a thin sheet-like structure, a high specific surface area (925.00 m2/g), and a micro-meso-porosity suitable for sustainable energy storage applications. A density functional theory investigation indicated that the synergistic effects of N and S co-doping enhanced both conductivity and electrolyte ion (Na⁺) diffusion kinetics in HGPC samples. When the solid winery waste-derived HGPC was used in a supercapacitor (SC) cell assembly with a diglyme-based electrolyte, it delivered an operating voltage window of 2.0 V, which was about twice as wide as those reported for symmetric SCs and compared well with those of asymmetric/hybrid SCs. In addition, it had a specific capacitance of 32 F/g (at the cell level) with a high energy density of 17.7 Wh/kg at a power density of 303.42 W/kg and excellent cycling stability over 10,000 charge/discharge cycles. This work shows that the solid winery waste-derived HGPC can be utilized for future SCs technology by replacing costly commercial YP-50F carbon to provide enhanced energy storage in a sustainable, green manner.