Hierarchical porous carbon prepared from mulberry leaves for supercapacitors

Hierarchical porous carbons with high surface area are synthesized from biomass mulberry leaves, by a hydrothermal carbonization and followed NaOH activation. The properties and the performances of the carbons are greatly influenced by the mass ratio of NaOH to the carbonized chars. The sample prepared with NaOH/char of 3:1 possesses hierarchical porous structure with a large specific surface area of 2662 m 2 g −1 and high content of heteroatoms (N 1.38%, O 9.73%). As a result, the carbon exhibits a high capacitance of 330 F g −1 in 6 M KOH and good cycle stability with a capacity retention of 88% after 10,000 cycles at 5 A g −1 .