Foaming waste wine yeast mud into nitrogen doped porous carbon framework by recyclable activator for high specific energy supercapacitor

Abstract

Biomass-derived carbon materials have received extensive attention in the field of energy storage and conversion due to their renewability, environmental protection, and rich in heteroatoms. Herein, waste wine yeast mud-derived nitrogen doped porous carbon framework (WMCF) has been prepared via a one-step simultaneous activation, foaming and nitrogen doping strategy using the non-toxic and recyclable Na2CO3 as the activating agent. The fabricated WMCF has a large specific surface area (1274.3 m2 g−1), developed mesopores structure and high nitrogen doping content (7.2 wt%), which significantly improves the electrochemical performance. As an electrode material for supercapacitor, the typical WMCF-2 material exhibits high specific capacitance of 220 F g−1 at 0.5 A g−1 and excellent rate capability (80 % capacitance retention even the current density increases 40 times). Besides, symmetric supercapacitor based on WMCF-2 electrodes and ionic liquid (EMIMBF4) electrolyte exhibits a high energy density of 50.4 W h kg−1 at 500 W kg−1 operated in the voltage range of 4 V, and outstanding capacitance retention of 91 % after an ultra-long 10,0000 cycles. The green preparation of biomass-based porous carbon frameworks offers a promising strategy for realizing low-cost and high energy density supercapacitors.