Holey graphitic carbon nano-flakes with enhanced storage characteristics scaled to a pouch cell supercapacitor

Supercapacitors with holey graphitic carbon nano-flakes (HGCNF) capable of demonstrating large specific capacitance (SC) have been developed for the first time. The unique approach of applying an additional conducting layer of carbon fabric (CF) coated with HGCNF at both half-cells provides a significant enhancement in SC, from 323 to 1142 F g⁻¹, for the half cell and from 8 to 487 F g⁻¹ for the symmetric supercapacitor, when the architecture is modified from Ni/HGCNF//HGCNF/Ni to Ni/HGCNF/CF/HGCNF//HGCNF/CF/HGCNF/Ni. HGCNF is composed of macro- and meso- pores enabling facile and deep penetration of electrolyte ions across the cross-section, ensuring maximum utilization at high current densities. Peak energy and power densities of 68 Wh kg⁻¹ and 2.5 kW kg⁻¹, achieved for the Ni/HGCNF/CF/HGCNF//HGCNF/CF/HGCNF/Ni cell, are superior to many reported nano-carbons, including HGCNF/Ni or HGCNF/CF symmetric cells. The corresponding 3 V pouch cell, showed an excellent SC of 80 F g⁻¹.