Dual Tuning of Biomass-Derived Hierarchical Carbon Nanostructures for Supercapacitors: the Role of Balanced Meso/Microporosity and Graphene

摘要

Rational design of advanced carbon nanomaterials with a balanced mesoporosity to microporosity is highly desirable for achieving high energy/power density for supercapacitors because the mesopore can allow better transport pathways for the solvated ions of larger than 1?nm. Inspired by the inherent meso/macroporous architecture and huge absorption ability to aqueous solution of auricularia biomass, we demonstrate a new biomass-derived synthesis process for the three-dimensional (3D) few-layered graphene nanosheets incorporated hierarchical porous carbon (GHPC) nanohybrids. The as-prepared GHPC nanohybrids possess a balanced mesoporosity to microporosity with much improved conductivity, which is highly desirable for achieving high energy/power density for supercapacitors. As we predicted, they delivered a high specific capacitance of 256?F g?1 at 1?A g?1 with excellent rate capability (120?F g?1 at 50?A g?1) and long cycle life (92% capacity retention after 10000 cycles) for symmetric supercapacitors in 1?M H₂SO₄. Based on the as-obtained carbon materials, a flexible and all-solid-state supercapacitor was also assembled, which can be fully recharged within 10?s and able to light an LED even under bended state. Such excellent performance is at least comparable to the best reports in the literature for two-electrode configuration under aqueous systems.