Molten Salt-Mediated Porous Carbon Derived From Litchi Peel for High-Performance Supercapacitors

Because of its abundant availability and potential for carbon conversion, litchi peel has been selected as a biomass carbon precursor. By utilizing a NaCl/ZnCl 2 mixed salt as an activating agent, a series of hierarchical litchi peel porous carbon materials (designated as NZ-LPPC- x - y , where x denotes the mixed salt-to-LP mass ratio, and y signifies the activation temperature) were successfully synthesized. Among them, NZ-LPPC-3-700 exhibited the largest specific surface area (1712.37 m 2  g −1 ) and pore volume (0.94 cm 3  g −1 ). Electrochemical testing revealed that NZ-LPPC-3-700 demonstrated favorable capacitive performance in 6 M KOH electrolyte, achieving high specific capacitance of 254.5 F g −1 at 1 A g −1 , while maintaining a capacitance retention rate close to 78.30% at 20 A g −1 . In a two-electrode system, the NZ-LPPC-3-700//NZ-LPPC-3-700 exhibited low equivalent series resistance and charge transfer resistance, along with energy density of 8.25 Wh kg −1 . Furthermore, it demonstrated remarkable cycling stability, retaining 96.6% of its initial capacitance after 20,000 consecutive charge–discharge cycles 10 A g −1 . Graphical