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An experimental study on PEO polymer electrolyte based all-solid-state supercapacitor.

机译：基于PEO聚合物电解质的全固态超级电容器的实验研究。

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摘要

Supercapacitors are one of the most important electrochemical energy storage and conversion devices, however low ionic conductivity of solid state polymer electrolytes and the poor accessibility of the ions to the active sites in the porous electrode will cause low performance for all-solid-state supercapacitors and will limit their application. The objective of the dissertation is to improve the performance of all-solid-state supercapactor by improving electrolyte conductivity and solving accessibility problem of the ions to the active sites.;The low ionic conductivity (10-8 S/cm) of poly(ethylene oxide) (PEO) limits its application as an electrolyte. Since PEO is a semicrystal polymer and the ion conduction take place mainly in the amorphous regions of the PEO/Lithium salt complex, improvements in the percentage of amorphous phase in PEO or increasing the charge carrier concentration and mobility could increase the ionic conductivity of PEO electrolyte. Hot pressing along with the additions of different lithium salts, inorganic fillers and plasticizers were applied to improve the ionic conductivity of PEO polymer electrolytes. Four electrode methods were used to evaluate the conductivity of PEO based polymer electrolytes. Results show that adding certain lithium salts, inorganic fillers, and plasticizers could improve the ionic conductivity of PEO electrolytes up 10-4 S/cm. Further hot pressing treatment could improve the ionic conductivity of PEO electrolytes up to 10-3 S/cm. The conductivity improvement after hot pressing treatment is elucidated as that the spherulite crystal phase is convert into the fringed micelle crystal phase or the amorphous phase of PEO electrolytes.;PEO electrolytes were added into active carbon as a binder and an ion conductor, so as to provide electrodes with not only ion conduction, but also the accessibility of ion to the active sites of electrodes. The NaI/I 2 mediator was added to improve the conductivity of PEO electrolyte and provide pseudocapacitance for all-solid-state supercapacitors. Impedance, cyclic voltammetry, and gavalnostatic charge/discharge measurements were conducted to evaluate the electrochemical performance of PEO polymer electrolytes based all-solid-state supercapacitors. Results demonstrate that the conductivity of PEO electrolyte could be improved to 0.1 S/cm with a mediator concentration of 50wt%. A high conductivity in the PEO electrolyte with mediator is an indication of a high electron exchange rate between the mediator and mediator. The high electron exchange rates at mediator carbon interface and between mediator and mediator are essential in order to obtain a high response rate and high power. This automatically solves the accessibility problem. With the addition of NaI/I2 mediator, the specific capacitance increased more than 30 folds, specific power increased almost 20 folds, and specific energy increased around 10 folds. Further addition of filler to the electrodes along with the mediator could double the specific capacitor and specific power of the all-solid-state supercapacitor. The stability of the corresponded supercapacitor is good within 2000 cycles.
机译：超级电容器是最重要的电化学能量存储和转换设备之一，但是固态聚合物电解质的离子电导率低以及离子对多孔电极中活性位的可及性差，将导致全固态超级电容器的性能下降。将限制其应用。本文的目的是通过提高电解质的电导率和解决离子对活性位的可及性问题来提高全固态超级电容器的性能。聚乙烯的低离子电导率（10-8 S / cm）氧化物（PEO）限制了其作为电解质的应用。由于PEO是半结晶聚合物，并且离子传导主要发生在PEO /锂盐复合物的非晶区中，因此，改善PEO中非晶相的百分比或增加电荷载流子浓度和迁移率可以提高PEO电解质的离子电导率。热压以及添加不同的锂盐，无机填料和增塑剂可改善PEO聚合物电解质的离子电导率。使用四种电极方法评估PEO基聚合物电解质的电导率。结果表明，添加某些锂盐，无机填料和增塑剂可以将PEO电解质的离子电导率提高10-4 S / cm。进一步的热压处理可以将PEO电解质的离子电导率提高到10-3 S / cm。阐明了热压处理后电导率的改善，因为球晶晶相转变为PEO电解质的条纹胶束晶相或非晶相。;将PEO电解质作为粘合剂和离子导体添加到活性炭中，从而使电极不仅具有离子传导性，而且使离子可接近电极的活性位。添加NaI / I 2介体可改善PEO电解质的电导率，并为全固态超级电容器提供伪电容。进行了阻抗，循环伏安法和恒静电荷/放电测量，以评估基于PEO聚合物电解质的全固态超级电容器的电化学性能。结果表明，当介体浓度为50wt％时，PEO电解质的电导率可以提高到0.1 S / cm。具有介体的PEO电解质中的高电导率表明介体和介体之间的电子交换速率高。为了获得高响应速率和高功率，在介体碳界面处以及介体与介体之间的高电子交换率至关重要。这将自动解决可访问性问题。添加NaI / I2介体后，比电容增加了30倍以上，比功率增加了近20倍，比能量增加了约10倍。与介体一起向电极中进一步添加填充剂可使全固态超级电容器的比电容器和比功率增加一倍。对应的超级电容器的稳定性在2000个周期内良好。

著录项

  • 作者

    Yijing, Yin.;

  • 作者单位

    University of Miami.;

  • 授予单位 University of Miami.;
  • 学科 Engineering Mechanical.;Engineering Materials Science.;Energy.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 179 p.
  • 总页数 179
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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