Highly Porous Holey Carbon for High Areal Energy Density Solid-State Supercapacitor Application.

Biomass materials are perceived as sustainable, carbon-rich precursors for the fabrication of carbon materials. In this study, we demonstrated the capacitance performance of biomass-derived carbon, produced by using golden shower tree seeds (GTs) as carbon precursors and potassium ferrate (K ₂ FeO ₄ ) as the activation agent. The as-prepared porous carbon (GTPC) possessed an ultrahigh specific surface area (1915 m ² g ^-1 ) and abundant pores. They also exhibited superior electrochemical performance, owing to their well-constructed porous structure, high surface area, and optimized porous structure. Optimized activated carbon (GTPC-1) was used to assemble a symmetric solid-state supercapacitor device with poly(vinyl alcohol) (PVA)/H ₂ SO ₄ as a solid-state gel electrolyte. The device exhibited a maximum areal energy density of 42.93 µWh cm ^-2 at a power density of 520 µW cm ^-2 .