Multicomponent doped hierarchically porous carbon derived from natural polyelectrolyte for high-performance supercapacitors

Natural polyelectrolyte complex has designable structure, unique advantages of composite and strong intermolecular or intramolecular force without chemical cross-linking agents, showing the advantages of good biodegradability and low toxicity. This work reports an application research of natural polyelectrolyte in energy storage device. A multi-doped hierarchically porous carbon is fabricated from polyelectrolyte of sodium lignosulfonate and chitosan and used as electrode material of supercapacitor. The material characterization reveals its large specific surface area of 1768 m² g⁻¹, pore volume of 0.94 cm³ g⁻¹ with optimum 3D porous structure, and high heteroatom (oxygen, nitrogen, and sulfur) concentration. Benefit from these, the electrodes it made exhibit 354 F g⁻¹ specific capacitance at 1 A g⁻¹ current density, outstanding rate retention of 82.9% at a testing environment of 20 A g⁻¹, and 97.8% capacitance retention in 3 M KOH electrolyte after 10 000 cycles. Using this material, all-solid symmetric supercapacitor devices show 30.11 Wh kg⁻¹ energy density at 520.88 W kg⁻¹ power density and retains 20.90 Wh kg⁻¹ at 1.03 kW kg⁻¹. These remarkable electrochemical performances prove the promising porous carbon in this work as electrode material with excellent performance for supercapacitors.