Rich sulfur doped porous carbon materials derived from ginkgo leaves for multiple electrochemical energy storage devices

A strategy of utilizing biomass in energy applications has been highly sought after due to low cost, renewability and environmental friendliness. In this work, based on the unique multilayered structure of ginkgo leaves, an interconnected carbon nanosheet with rich micro/meso pores has been fabricated using hydrothermal treatment and a KOH activation process. Attractively, due to the intensive reactions between the rich organism components of the ginkgo leaves and sulfuric acid in the preparation process, the highest amount of sulfur doping (8.245 wt%) ever reported has been achieved in the as-obtained biomass derived carbons. Combined with the N doping derived from the proteins in ginkgo leaves, S,N dual-doping porous carbons with an interconnected sheet-like structure demonstrate excellent electrochemical performance in both EDLCs and NIBs. The application in EDLCs in aqueous electrolyte showed a high specific capacitance of 364 F g−1 at 0.5 A g−1 and only 2% capacitance loss after 30 000 cycles. In an ionic liquid electrolyte, the devices were able to deliver an energy density of 16 W h kg−1 at an extremely high power density of 50 kW kg−1. As a sodium-ion battery anode, it has the capacity of 200 mA h g−1 after 500 cycles (99% capacity retention) at 0.2 A g−1, which is superior or at least comparable to those of biomass derived carbons reported recently. Therefore, all these results exhibit the promising potential of the ginkgo leaves-derived carbon for wide applications in the field of energy storage devices.