增塑剂对PVA碱性聚合物电解质电化学性能的影响

通过溶解―铸膜法制备聚乙烯醇(PVA)-KOH-H2O碱性聚合物电解质膜。向聚合物中添加增塑剂丙三醇(GROL)和碳酸丙烯酯(PC)来提高离子电导率。X射线晶体衍射分析(XRD)结果表明,添加增塑剂未改变聚合物的物相结构,薄膜仍主要为不定形态。差示扫描热分析(DSC)结果显示,添加增塑剂后聚合物电解质膜的玻璃化转变温度降低,促进了电解质膜向不定形态转变。电解质膜室温离子电导率随增塑剂添加而增大,增塑剂超过一定量后离子电导率开始下降。PC对提高离子电导率的作用优于GROL。循环伏安测试结果显示,电解质膜的电化学稳定性窗口随增塑剂的添加而有所变窄,但仍显示了较好的电化学稳定性。

Effect of Plasticizers on Electrochemical Properties of Alkaline PVA Polymer Electrolyte

An alkaline poly(vinylalcohol)(PVA) electrolyte membranes were prepared by a solution-casting method.Plasticizers,glycerol(GROL) and propylene carbonate(PC),were added to improve the ionic conductivity of the electrolyte.X-ray diffraction(XRD) results showed that the addition of plasticizers did not change the crystallinity of PVA.The membranes still showed an amorphous phase.The differential scanning calorimetry(DSC) results indicated that the addition of plasticizers would promote the transformation to amorphous phase.Electrochemical impedance spectrocopy results showed that the electrolyte’s ionic conductivity increased firstly with the addition of plasticizers,and when the content of plasticizers exceeded an certain extent,the ionic conductivity decreased.The addition of propylene carbonate(PC) made more effective at increasing the ionic conductivity than that of GROL.The electrochemical stability windows narrowed a little with the addition of plasticizers,but the polymer electrolyte membranes had promising electrochemical stabilities.