一种高离子电导率水凝胶聚合物电解质的制备及性能

Preparation and properties of a hydrogel polymer electrolyte with high ionic conductivity

具有高离子电导率且综合性能优异的凝胶电解质是储能材料领域的研究热点。以简单的冻融法制备了一种基于聚乙烯醇(PVA)和壳聚糖(CS)的水凝胶聚合物电解质,并获得高离子电导率。系统地探索了水凝胶冷冻时间、浸泡电解液的时间以及电解液种类对水凝胶离子电导率的影响,得出了适合该物理交联PVA/CS凝胶电解质的制备条件。结果表明:PVA与CS质量比为1∶2,经过5h冷冻12h解冻获得的凝胶具有较均匀的三维孔洞结构和较低的结晶度,没有发生水凝胶无限溶胀以及溶解的现象。该水凝胶浸泡饱和NaCl电解液6h后其离子电导率达到最大值1.68S/cm,浸泡1mol/L H_(2)SO_(4)电解液的离子电导率在4h时最大为0.83S/cm。此外,5mm厚的水凝胶在12h后达到溶胀平衡,体积和质量溶胀率分别约为170%和145%;凝胶断裂伸长率在室温下可以达到200%左右。

Gel electrolyte with high ionic conductivity and excellent comprehensive performance is a research hotspot in the field of energy storage materials.A hydrogel polymer electrolyte based on polyvinyl alcohol(PVA)and chitosan(CS)was prepared by a simple freeze-thaw method,and high ionic conductivity was obtained.The effects of hydrogel freezing time,soaking time in the electrolyte,and the types of electrolytes on the ionic conductivity of the hydrogel were systematically explored.The suitable preparation conditions for the physical crosslinking PVA/CS gel electrolyte were obtained.The results showed that the PVA/CS gel had a relatively uniform three-dimensional-hole structure and low crystallinity when the mass ratio of PVA to CS was 1∶2,and the hydrogel was frozen for 5h and thawed for 12h.No infinite swelling and dissolution of the hydrogel occurred.The ionic conductivity of the hydrogel soaked in saturated sodium chloride electrolyte for 6h and 1mol/L H_(2)SO_(4)electrolyte for 4h reached the maximum value of 1.68S/cm and 0.83S/cm,respectively.Additionally,the 5mm-thick hydrogel reached swelling equilibrium after 12h,the volume and mass swelling rates of hydrogel were about 170%and 145%,respectively,and the elongation at break could reach about 200%at room temperature.