Polypyrrole-coated paper for flexible solid-state energy storage

Highly conductive paper was fabricated through polypyrrole (PPy) coating on common printing paper by a simple and low-cost soak and polymerization method. The as-fabricated porous, flexible and conductive paper shows a high electrical conductivity of 15 S cm(-1) and a low sheet resistance of 4.5 Omega sq(-1). Flexible solid-state super-capacitors assembled with PPy/paper composite electrodes had an average weight of 55 mg and an areal capacitance of 0.42 F cm(-2), indicating a high energy density of 1 mW h cm(-3) at a power density of 0.27 W cm(-3) normalized to the volume of the whole cell (electrode, electrolyte, and separator). Furthermore, this method could be easily scaled up to large-scale fabrication of conductive paper and opened up new opportunities for flexible energy storage.