Carbonized wood-based electrode anchored with Cu/Cu3P Nano particles fabricated from wood-based adsorbent for boosting capacitive performance

In this study, phosphorylated Paulownia wood is used as a starting material to construct self-supporting supercapacitor electrodes by carbonization after adsorption of Cu2+ in simulated wastewater at low concentrations. The specific capacitance of the electrodes is synergistically improved by increasing the specific surface area, doping with heteroatoms and loading with pseudocapacitive substances. The electrodes are systematically characterized through various techniques, and the results show that the adsorbed Cu2+ was converted into Cu/Cu3P NPs during the carbonization process. The electrochemical performance of different electrodes is characterized and compared. CPEW-Cu90 is identified as the optimal electrode, and its specific surface area is 731.96 cm2 g−1, nitrogen doping amount is 1.88 %, and copper loading amount is 22.85 % (the molar ratio of Cu to Cu3P was 0.40:1). In terms of electrochemical performance, CPEW-Cu90 has an Rct of 2.18 Ω and a mass specific capacitance of 481.2 F g−1 at a current density of 100 mA g−1, the assembled self-supporting symmetric supercapacitor exhibits an energy density of 18.67 W h−1kg−1 and excellent structural stability, and its capacitance remains at 93.08 % after 1000 cycles. Overall, a self-supporting, low-cost, high-performance carbonized wood-based supercapacitor is fabricated from the wood-based adsorbent.