Polyphosphate based electrochemical capacitors

Environmentally friendly electrochemical capacitors (ECs) were assembled using hybrid materials formed by a polyphosphate gel matrix in which carbon-based materials were inserted and polyaniline were formed in a single-step synthesis. The hybrid materials were deposited on FTO glasses and symmetric ECs were assembled using a cellulose membrane soaked with an aqueous NaH2PO4 solution as a separator. The capacitance values were calculated from impedance spectroscopy and galvanostatic charge/discharge measurements. The devices showed capacitances ranging from 4.0 to 27.0 F cm−3, which are comparable to some commercial devices. Better results were achieved in samples with polyaniline, which were ascribed to the pseudocapacitance impaired to the samples by the conducting polymer.