Sustainable activated carbons from dead ginkgo leaves for supercapacitor electrode active materials

The practical applications of some advanced carbon nanomaterials in supercapacitors are still hampered by the resource scarcity and high cost. It arouses great interest to seek for ample and low-cost substitutes to meet the need of upcoming large-scale productions. The chemical conversion of renewable and abundant biomass provides a good opportunity for the economic and sustainable synthesis of carbon based electrode materials. In this work, activated ginkgo leaf-derived carbons were investigated as porous cheap biomass carbons with utility as supercapacitor electrode materials in the acid electrolyte. The influences of KOH-, ZnCl2-, and H3BO3-activations on the composition, morphology and performance of as-prepared carbons were studied and discussed. Benefiting from the superior electrochemical activity endowed by the hierarchical nano-architecture and abundant oxygen-containing groups, the as-obtained KOH-activated ginkgo leaf-derived carbon material exhibited the best specific capacitance (374F g−1 at 0.5 A g−1) relative to pristine carbon, ZnCl2-, and H3BO3-activated carbons. And this KOH-activated ginkgo leaf-derived carbon in the two-electrode configuration also demonstrated satisfactory specific capacitance (272F g−1 at 0.2 A g−1) and cycling reliability. Moreover, these performances also outperform those of some similar carbon materials.