Wood-derived flexible supercapacitors for anti-freezing green power sources

Abstract

Highly porous wood-derived electronics have attracted tremendous attention for the fabrication of high-performance supercapacitors (SCs) owing to their environmental benignity, natural abundance, renewability, and biodegradability. However, it is challenging to overcome the intrinsic rigidity and sluggish electrochemical reaction kinetics of wood-based SCs at low temperatures. Herein, we demonstrate an anti-freezing flexible SC (AF-FSC) based on delignified wood electrodes with an organohydrogen electrolyte. The chemical delignification process removes hemicellulose and lignin from natural wood, resulting in a softwood skeleton electrode. When assembled with a solid hydrogel electrolyte, the AF-FSC exhibits high mechanical flexibility over 93% capacitance retention after 1000 bending/twisting cycles at −30 °C. Besides, high areal capacitance (285.2 mF cm⁻²) at −30 °C is achieved, which is higher than most wood derivatives operating at room temperature. The unique properties of the anti-freezing flexible AF-FSC make it a green renewable power source for driving multi-functional electronic components in real-life scenarios.