Phytic acid assisted preparation of high-performance supercapacitor electrodes from noncarbonizable polyvinylpyrrolidone

Fabrication of carbon electrodes from noncarbonizable materials offers great potential to prepare high-performance supercapacitors at low cost. The present work reports a simple yet effective strategy for the preparation of hierarchical porous carbons using noncarbonizable polyvinylpyrrolidone (PVP) as a precursor. Thanks to the flame-retardant effect of phytic acid (PA), high carbonization yield of up to 40 wt% is obtained for the PVP-derived carbons. The subsequent activation endows the carbon material to have a hierarchical porous nanostructure with high surface area. The optimized aHPC-3-400 sample shows ultrahigh surface area (3090 m² g^-1) with moderate nitrogen (2.68 wt%) and abundant oxygen concentrations (23.47 wt%). The as-prepared electrode exhibits a high specific capacitance of 406 F g^-1 at 1 A g^-1 in 6 M KOH aqueous electrolytes. Remarkably, the assembled symmetric supercapacitor displays a high energy density of up to 28.9 W h kg^-1 with a slight capacitance loss of 2% even after 10000 cycles. These results suggest that the flame retardant inspired stabilization strategy would provide a viable avenue for the preparation of high-quality carbon materials from noncarbonizable precursors.