Biomass-Derived N/O/P Tri-Doped Hierarchically Porous Carbon with a Wider Potential Window for Flexible Energy Storage Devices

Abstract

Waste biomass shows great potential as a carbonaceous electrode material candidate for energy storage devices due to its abundant element composition and renewability. Here, we propose a facile approach to prepare N/O/P tri-doped hierarchical porous carbon electrode materials via forming a hydrogel with chitosan and phytic acid through electrostatic and hydrogen bonding. The as-samples exhibit large specific surface area, hierarchical pore structure and plentiful heteroatom doping. As the electrode materials, APC-2 achieves high specific capacitance of 320 F g−1 at 1 A g−1 and extraordinary cycling stability with 97% capacitance retention after 10000 cycles. Remarkably, by P-doping the voltage window of assembled symmetric supercapacitor is widened to 1.3 V in alkaline electrolyte and 1.7 V in neutral electrolyte. The energy density is up to 15.82 W h kg−1 at the power density of 850 W kg−1 in Na2SO4 electrolyte. These outstanding performance indicated that the facile conversion of renewable biomass hold prominent prospect for the sustainable applications in energy storage devices.