Wood-derived biochar supported polypyrrole nanoparticles as a free-standing supercapacitor electrode

Abstract

Paulownia wood processing residues were adopted as both a template and precursor for the synthesis of a wood-derived biochar/polypyrrole (coded as WDB/PPy) composite via a simple cost-effective in situ chemical oxidative polymerization method. The WDB substrate was encapsulated with plenty of PPy nanoparticles with diameters of a few hundred nanometers, and the resultant WDB/PPy composite can be utilized as a free-standing and binder-free supercapacitor electrode. This hybrid electrode has a high specific capacitance of 216 F g⁻¹ at 0.05 A g⁻¹, an excellent coulombic efficiency of more than 98%, and a favorable cyclic stability with 96.9% capacitance retention after 3000 cycles. These results offer a low-cost eco-friendly design of electrode materials for supercapacitors. More importantly, this cheap and environmentally benign WDB substrate is expected to integrate with more types of electrochemically active substances to develop novel energy storage devices.