Glucose-assisted grapevine-based ultrahigh microporosity activated hydrochar materials for supercapacitor electrodes

The doping of heteroatoms during the preparation of hydrothermal carbon represents an effective technology for the improvement of doped carbon materials for supercapacitors (SCs). In this study, N/S-doped hydrothermal carbon was prepared via a glucose-assisted glucose self-doping process during the hydrothermal carbonization stage. In addition, heteroatom-doped carbon materials for supercapacitors were prepared by KOH activation treatment, and their high specific surface area and microporous structure rate can be attributed to the stable structure of glucose and the large amount of heteroatoms in grapevines. It exhibited an amazing specific capacitance of 521.0 F/g at a current density of 0.5 A/g, an energy density of 49.6 W h/kg for symmetric devices, and a power density of 0.5 kW/kg. After 25,000 charge and discharge cycles under constant current conditions, the capacitance retention rate can still reach 86.99 %. This study proposes a new method for preparing heteroatom-doped carbon materials for supercapacitors using waste biomass.