Preparation of V₂O₅ / PPy composites and their electrochemical performance

The composites of polypyrrole ( PPy) and vanadium pentoxide (V₂O₅ ) were synthesized by chemicaloxidative polymerization. By using different methods of adding oxidant , different st ructure composites wereobtained. The conductivities of the composites were measured by a four-probe instrument . The composites were investigated and characterized by BET , XRD and SEM. The result s show that the composites obtained by using differentmethods of adding the oxidant have different st ructures and morphologies. When the oxidant is added into the reaction vessel first , polypyrrole intercalates into the sandwich of V₂O₅ . When the pyrrole is added into the reaction vessel first , PPy deposit s preferentially on the V₂O₅ particle surface. To study the elect rochemical performance of composites , button-type lithium secondary batteries were fabricated with the composites as anodes. The elect rochemicalproperties as anodes were investigated with galvanostatic charge-discharge test and A. C. impedance spect roscopy.It was found that the V₂O₅ / PPy composite obtained by adding oxidant first possessed excellent elect rochemical performance. The highest discharge capacity of V₂O₅ / PPy anode reached 230 mAh/ g.