High-mass loaded redox-active lignin functionalized carbonized wood collector to construct sustainable and high-performance supercapacitors

Traditional electrode materials for supercapacitors often face issues like high toxicity, cost, and non-renewability. To address these drawbacks, biomass-based alternatives are being explored, aligning with green development trends. Herein, carbonized wood (CW) with rich pore structure and redox-active lignin are combined to fabricate an all-wood-based sustainable supercapacitor electrode material. Due to its inherent porous structure, CW provides a larger surface area for accommodating active materials ion, enabling the electrode to achieve a higher lignin loading capacity of 2.82–11.68 mg/cm2. Furthermore, the utilization of lignin as a substitute for conventional transition metal-based pseudocapacitor material functionalized CW endows the electrode with exemplary electrochemical performance while guaranteeing the comprehensive sustainability of the electrode. This synergy confers the electrode with exceptional electrical performance, yielding an areal capacitance of 960.7 mF/cm2 at a current density of 1 mA/cm2. The symmetric supercapacitors (SSC) manufactured by this composite electrode can achieve a notable areal energy density of 0.14 mWh/cm2 and a power density of 15.98 mW/cm2, while maintaining an outstanding capacitance retention rate of 81 % after 50,000 cycles at 20 mA/cm2. The manufacture of CW-lignin electrode underscores the potential of utilizing renewable biomass resources as alternatives for developing high-performance energy storage applications, thereby reducing negative environmental impacts.