Boosting the capacity of biomass-based supercapacitors using carbon materials of wood derivatives and redox molecules from plants

A hybrid system electrode made from a biomass-based material sodium lignosulfonate-derived hierarchical porous graphitic carbon (PGLS) and an organic redox compound (alizarin) is demonstrated. A derivative of alizarin called alizarin red S (ARS) improves energy storage capacity while PGLS-1 synthesized from high-molecular-weight sodium lignosulfonate (LS), using K2FeO4 to achieve synchronous carbonization and graphitization, provides a continuous 3D porous framework with a certain graphitic order for the bulk charge transport and ARS self-organization within the composite electrode. The composite ARS/PGLS-1 electrode exhibits outstanding gravimetric specific capacitances (469.5 and 200.2 F g(-1) at current densities of 0.5 and 10.0 A g(-1), respectively, for the ARS/PGLS-1 = 1 sample), indicating that ARS is compatible with PGLS-1 carbon-based supercapacitor systems that can be produced on a large scale. Furthermore, the assembled symmetric prototype redox-enhanced supercapacitor (SPRS) in an aqueous gel electrolyte (PVA/KOH/ARS) is demonstrated to have considerable specific capacitance, operational stability of over >2000 cycles, and synergetic energy-power output characteristics in practical applications. This new class of supercapacitors based on biomass materials represents a significant step toward green and sustainable energy storage technologies.

Automated summary

A hybrid electrode system made from biomass-based material and an organic redox compound has been demonstrated to enhance energy storage capacity and exhibit outstanding specific capacitance and operational stability. This new class of supercapacitors shows great potential for green and sustainable energy storage technologies.