K2FeO4-Zn碱性固态电解质电池电化学性能研究

应用溶液铸膜法制备出了交联聚乙烯醇(PVA)/聚丙烯酸(PAA)-KOH-H2O复合碱性固态电解质膜, 其厚度为150 µm左右, SEM测试结果表明其表面呈均相的非晶态结构, 交流阻抗(EIS)测试表明室温离子电导率可达3.5×10－2 S• cm－1, 循环伏安(CV)测试表明其电化学稳定窗口为3.5 V左右, 将其应用于一次碱性K2FeO4-Zn电池, 通过研究固态电解质膜在不同浓度KOH碱液中预处理和其在不同放电倍率下的放电性能, 结果表明, 9 mol•L－1为最佳固态电解质膜预处理碱液浓度, 0.4 C为最佳放电倍率, 1.0 V以上容量最高可达222.6 mAh•g－1, 并表现出良好的放电平台特性.

Electrochemical Property of K2FeO4-Zn Alkaline Solid Electrolyte Battery

Composite alkaline crosslinked PVA/PAA-KOH-H2O solid polymer electrolyte membranes were prepared with a solution-casting method. Scanning electron microscope (SEM) micrographs showed that the membrane surface had a uniform amorphous structure. The ionic conductivity of the polymer electrolyte membranes at room temperature was investigated by AC impedance spectroscopy, which could reach 3.5×10－2 S•cm－1. Also the electrochemical stability window has been investigated by cyclic voltammetry (CV), showing that it was about 3.5 V. It was suggested that the composite alkaline polymer electrolyte membranes could be used for solid-state K2FeO4-Zn primary alkaline batteries. With the pretreatment of the solid polymer electrolyte membranes in KOH solution with different concentrations and under different discharge rates, the discharge performance of the solid-state K2FeO4-Zn batteries was studied. The results suggested that the best concentration of KOH in which the membranes were pretreated was 9 mol•L－1, and the best discharge rate was 0.4 C. The discharge capacity above 1.0 V was up to 222.6 mAh•g－1 with a preferable discharge voltage plateau.