五氧化二钒/聚吡咯的制备及其电化学性能

采用化学氧化法, 通过改变氧化剂的加入方式, 制备了不同结构的五氧化二钒/ 聚吡咯(V₂O₅ / PPy) 复合材料。用四探针测试了材料的电导率, 并用比表面积(BET) 、X 射线粉末衍射(XRD) 和扫描电子显微镜(SEM)对复合材料进行了测试和表征。结果表明: 氧化剂的加入方式不同, 所得复合材料的结构和形貌明显不同。在反应器内先加入氧化剂时, 吡咯在V₂O₅ 的层间聚合; 在反应器内先加入吡咯单体时, 吡咯在V₂O₅ 的表面吸附聚合。为研究不同结构复合材料的电化学性能, 将V₂O₅ / PPy 作为锂二次电池正极, 组装成扣式电池, 采用恒电流充放电及交流阻抗法对复合正极材料进行测试。结果表明: 采用先加入氧化剂方式所得材料的电化学综合性能最好, 锂二次电池的最高放电比容量达230 mAh/ g。 

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.