论文总字数：19507字

摘 要

锌空气电池成本低廉、比能量高、无污染、稳定性高，是很有潜力的电池能源，但至今很难在市场上大规模推广部署。锌空气电池循环寿命短、电极容易失效通常由锌电极的枝晶、形变、钝化和腐蚀，电解液的泄露、浸出和蒸发等原因引起。现有研究表明，聚合物电解质的引入能够有效改善以上问题，但电池的性能方面仍旧差强人意。本文将在前人的研究基础上，通过对PVA-KOH聚合物电解质进行改性，探寻更优的锌空气电池。本文采用溶解-铸膜法制备PVA-KOH聚合物电解质，通过搅拌法掺杂无机纳米填料（ZnO和SiO₂），以此为基础，使用XRD、扫描电镜、傅里叶红外光谱检测、热重分析、交流阻抗法、循环伏安法、循环充放电发等技术表征聚合物电解质膜和锌空气电池的性能。研究表明：当PVA:H₂O=1:4时易于成膜，自然成膜后的膜内水分占比约为11.6%，吸液率约为81%，离子电导率约为17.610^-3 S/cm，达到10^-2 S/cm级别。ZnO与PVA基体发生物理作用，与此同时还可缓解锌电极的自腐蚀，延长电池寿命。掺杂SiO₂后PVA-KOH聚合物电解质的结合水量升高。ZnO和SiO₂同时引入，可改善PVA-KOH聚合物电解质的离子电导率，阻碍PVA基体再结晶，增加非晶相结构，降低膜的玻璃态转变温度。与PVA形成相互连接的网络改善了热稳定性，重量损失的百分比降低，保水率有提升。改性后的PVA基聚合物电解质膜电化学性能更稳定，采用改性后聚合物电解质膜的锌空气电池，电容量保持率更高，循环寿命更长。

关键词：碱性聚合物电解质；聚乙烯醇；锌空气电池；二氧化硅；氧化锌；电化学性能

Preparation and modification of PVA-KOH polymer electrolyte

for zinc-air battery

Abstract

Zinc-air battery is a kind of potential battery energy with low cost, high specific energy, free-pollution and high stability, but it is difficult to promote and deploy it widely in the market. The short cycle life of zinc-air batteries and the failure of electrodes are usually caused by dendrites, deformation, passivation and corrosion of zinc electrodes, electrolyte leakage, leaching and evaporation. The existing research shows that polymer electrolyte can improve the above effectively , but the zinc-air battery’s performance is unsatisfactory. In this paper, we explore a better zinc-air battery by modifying PVA-KOH polymer electrolyte on the basis of previous studies. In the experiment, PVA-KOH polymer electrolyte is prepared by solution -casting method, and inorganic nanofillers (ZnO and SiO₂) are doped by mixing. The properties of polymer electrolyte membrane and zinc-air battery are characterized by XRD, SEM, FTIR, TG-DSC, EIS, CV and cyclic charge discharge. The studies show that when PVA:H2O=1:4, it is easy to form a film. The natural film has a water content of about 11.6%, a liquid absorption rate of about 81%, and an ion conductivity of about 17.610^-3S/cm, which reaches 10^-2S/cm level. The physical interaction between ZnO and PVA matrix can relieve the self-corrosion of zinc electrode and prolong the battery life. The amount of bound water of PVA-KOH polymer electrolyte increases after doping with SiO₂. The simultaneous introduction of ZnO and SiO₂ can improve the ionic conductivity of the PVA-KOH polymer electrolyte, hinder the recrystallization of the PVA matrix, increase the amorphous phase structure, and reduce the glass transition temperature of the film. The interconnected network with PVA improves thermal stability, the percentage of weight loss is reduced, and the water retention rate is improved. The modified PVA polymer electrolyte membrane’s electrochemical performance becomes more stable. The zinc-air battery’s capacity retention rate is higher and cycle life is longer than before because of useing the membrane.

Key words: Alkaline polymer electrolyte；PVA ； Zinc-air battery； SiO₂；ZnO；

Electrochemical property

目 录

摘 要 I

Abstract II

第一章 绪 论 1

1.1论文研究的目的和意义 1

1.2 锌空气电池的简介 1

1.2.1 锌空气电池的组成及工作原理 2

1.2.2 锌空气电池中电解质材料存在的问题 2

1.3 聚合物电解质研究概述 2

1.3.1 聚合物电解质的种类 3

1.3.2 凝胶聚合物电解质研究 3

1.3.3 聚合物电解质的改性 4

1.4锌空气电池用PVA-KOH聚合物电解质 5

1.5 小结 6

第二章 研究内容及方法 7

2.1 研究内容 7

2.1.1 实验方案 7

2.1.2 实验仪器与材料 8

2.2 研究方法 9

2.2.1电化学性能测量 9

2.2.2聚合物电解质膜的表征 10

第三章 实验结果分析与讨论 12

3.1 PVA-KOH聚合物电解质膜的制备与表征 12

3.1.1 PVA凝胶的粘度及成膜后吸液率 12

3.1.2 PVA-KOH聚合物电解质膜的XRD分析 14

3.1.3 PVA-KOH聚合物电解质膜的TG-DSC分析 14

3.1.4 PVA-KOH聚合物电解质膜的SEM分析 15

3.1.5 PVA-KOH聚合物电解质膜的FTIR分析 16

3.1.6 PVA-KOH聚合物电解质膜的离子电导率 16

3.1.7 PVA-KOH聚合物电解质膜的电化学稳定性 17

3.2锌空气电池的性能评估 17

第四章 结论及展望 19

4.1本文结论 19

4.2问题与展望 19

参考文献 20

致 谢 22

第一章 绪 论

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