Surface modification of FePO4 particles with conductive layer of polypyrrole

Polypyrrole–FePO4 powder was synthesized by an oxidative polymerization of pyrrole monomer on the surface of FePO4 powder. The polymerization reaction was initiated using hydrogen peroxide in an acidified solution and catalysed with Fe3+. The samples were investigated by light microscopy (LM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). These methods confirmed the presence of polypyrrole on FePO4 particles and its homogeneous distribution in the composite material. To determine the PPy content in the PPy–FePO4 composites a thermogravimetric analysis was used. Cyclic voltammetry curves (CV) were measured and compared in a non-aqueous lithium salt solution for electrodes consisting of pellets made from pure FePO4 and FePO4/PPy. Electrochemical impedance spectroscopy (EIS) showed that coating of PPy significantly decreases the charge transfer resistance of PPy–FePO4 electrodes.

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