High-performance solid-state supercapacitors with designable patterns based on used newspaper

Abstract From the viewpoint of developing low-cost, eco-friendly and flexible energy storage devices, the used newspaper that consists of interconnected cellulose fibers was served as flexible substrate to fabricate solid-state supercapacitors. Graphite current collectors with desired patterns were directly coated on the used newspaper by pencil drawing and then three dimensional interconnected polypyrrole nano/microcones were electrochemically deposited on them, forming the newspaper-based graphite–PPy nano/microcones (NGP) electrodes. The effect of deposition time on the morphology and electrochemical properties of the NGP electrodes was investigated. The NGP electrode that obtained by electrochemical polymerization of pyrrole for 120 min showed a high specific capacitance of 1122 mF cm −2 (1 mA cm −2 ). Solid-state supercapacitors based on NGP electrodes with a sandwich structure and in-plane interdigital structure were fabricated, which exhibited excellent specific capacitance, energy density, power density, flexibility and voltage/current scalability. Other electrodes/supercapacitors with designable patterns also can be obtained by this simple method. These results indicate the NGP-based supercapacitors are promising in diverse portable and flexible electronics. Graphic abstract