Self‐Assembly/Sacrificial Synthesis of Highly Capacitive Hierarchical Porous Carbon from Longan Pulp Biomass

Exploration of efficient strategies for highly capacitive electrodes is of great significance for the development of advanced energy devices. Herein, we propose a novel method for the preparation of a hierarchical porous carbon material derived from longan pulp biomass for application in supercapacitors. First, a precursor of the two‐dimensional graphitized carbon with uniform carbon spheres is self‐assembled via a hydrothermal method with a post‐calcination process. After that, the longan pulp hierarchical porous carbon with inner pores is achieved through an embedding method with a mixture of precursor, KOH and KCl at high‐pressure and appropriate annealing temperature by self‐sacrificial means. The rich mesopores inside the sheet of LHPC‐3 demonstrate a more conducive strategy to create holes inside the materials, which is beneficial for electrical double‐layer capacitance. As a result, the LHPC‐3 is characterized with a high specific surface area of 1678 m 2  g −1 and an abundance of meso‐/micropores, which facilitate the electrolyte penetration and mass transfer rates. Accordingly, LHPC‐3 exhibits an excellent specific capacitance of 380 and 153 F g −1 at 0.5 A g −1 in three‐electrode and symmetric supercapacitor systems, respectively. The new synthesis strategy is more conducive to the internal pore formation of carbon materials and has the potential to be widely applied to the synthesis of other electrochemical materials.