聚乙烯醇-磷酸-硅钨酸聚合物电解质膜的制备及电化学性能

Preparation of PVA-H_3PO_4-STA Polymer Electrolyte Membranes and Their Electrochemical Properties

采用溶液浇铸法制备聚乙烯醇(PVA)-磷酸(H_3PO_4)-硅钨酸(STA)聚合物电解质膜,通过X-射线衍射(XRD)、傅立叶变换红外光谱(FTIR)、热重分析(TGA)对聚合物电解质膜进行了表征,采用交流阻抗法测定聚合物电解质膜的质子电导率,并分析了H_3PO_4含量对质子电导率的影响。结果表明,当STA含量不变时,随着H_3PO_4含量的增加,聚合物电解质膜的质子电导率先增大后减小;当m(PVA)∶m(H_3PO_4)∶m(STA)=1∶4∶8时,在室温下质子电导率达到最大值,为5.50×10^(-2) S·cm^(-1);H_3PO_4含量的增加使晶态PVA转变为非晶态,晶态PVA减少;循环伏安法和充放电测试结果表明,该聚合物电解质膜具有很好的电化学稳定性,有望应用于固态超级电容器。

Polyvinyl alcohol（PVA）-phosphoric acid（H_3PO_4）-silicotungstic acid（STA）polymer electrolyte membranes were prepared by a solution-casting method.The polymer electrolyte membranes were characterized by XRD,FTIR and TGA.The proton conductivity of the polymer electrolyte membranes was detected by an AC impedence method.Effect of H_3PO_4 content on proton conductivity was also discussed.Results showed that proton conductivity of the polymer electrolyte membranes increased firstly and then decreased with the increase of H_3PO_4 content when the STA content was constant.When m（PVA）∶m（H_3PO_4）∶m（STA）was 1∶4∶8,the polymer electrolyte membranes exhibited the highest proton conductivity of 5.50×10^（-2） S·cm^（-1） at room temperature.While increasing H_3PO_4 content,the crystallized PVA could be converted into amorphous phase,and content of the crystallized PVA reduced.The cyclic voltammograms and charge-discharge results indicated that the polymer electrolyte membranes had good electrochemical stability,and could be applied to solid supercapacitors.