Compositional Dependence of Li-Ion Conductivity in Garnet-Rich Composite Electrolytes for All-Solid-State Lithium-Ion Batteries-Toward Understanding the Drawbacks of Ceramic-Rich Composites.
Compositional Dependence of Li-Ion Conductivity in Garnet-Rich Composite Electrolytes for All-Solid-State Lithium-Ion Batteries-Toward Understanding the Drawbacks of Ceramic-Rich Composites.
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DOI：
10.1021/acsami.1c05846
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发表时间：
2021-06
影响因子：
9.5
通讯作者：
A. I. Waidha;Thimo H Ferber;Manuel Donzelli;Niloofar Hosseinpourkahvaz;V. Vanita;Klaus Dirnberger;S. Ludwigs;R. Hausbrand;W. Jaegermann;O. Clemens
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作者：
A. I. Waidha;Thimo H Ferber;Manuel Donzelli;Niloofar Hosseinpourkahvaz;V. Vanita;Klaus Dirnberger;S. Ludwigs;R. Hausbrand;W. Jaegermann;O. Clemens
由聚合物+锂盐基质和填充物组成的复合电解液具有高锂离子导电率、良好的机械性能、宽的电化学操作窗口和对金属锂的稳定性，这些都是发展高能量密度全固态锂离子电池的关键。本研究以聚环氧乙烷(PEO)为聚合物组分，采用雾化喷雾热解法制备了四方石榴石和立方石榴石的无溶剂复合电解液。用电化学阻抗谱(EIS)研究了一系列不同石榴石和不同重量分数的复合材料。结果表明，与无填料电解液相比，随着复合材料中陶瓷质量分数的增加，离子导电性降低，锂离子传输途径趋于可选。试图了解复合材料中的离子输运机制。通过对非导电陶瓷与锂导电聚合物共混体系的研究，解释了陶瓷填料的化学和形态性质在富聚合物和富陶瓷复合电解液中的作用，指出陶瓷填料的本征导电性对富陶瓷体系的整体导电过程有重要的贡献。进一步，通过X射线光电子能谱研究了石榴石/PEO界面的稳定性，并利用交流阻抗谱研究了其对锂离子输运的影响。
Composite electrolytes comprising a polymer plus Li salt matrix and embedded fillers have the potential of realizing high lithium-ion conductivity, good mechanical properties, wide electrochemical operational window, and stability against metallic lithium, all of which are essential for the development of high-energy-density all-solid-state lithium-ion batteries. In this study, a solvent-free approach has been used to prepare composite electrolytes with tetragonal and cubic phase garnets synthesized via nebulized spray pyrolysis with polyethylene oxide (PEO) being the polymer component. Electrochemical impedance spectroscopy (EIS) is used to examine a series of composites with different garnets and weight fractions. The results show that with the increase in the ceramic weight fraction in the composites, ionic conductivity is reduced and alternative Li-ion transport pathways become accessible for composites as compared to the filler-free electrolytes. An attempt is made to understand the ion transport mechanism within the composites. The role of the chemical and morphological properties of the ceramic filler in polymer-rich and ceramic-rich composite electrolytes is explained by studying the blends of nonconducting ceramics with the Li-conducting polymer, indicating that the intrinsic conductivity of the ceramic filler significantly contributes to the overall conductive process in the ceramic-rich systems. Further, the stability of the garnet/PEO interface is studied via X-ray photoelectron spectroscopy, and its impact on the lithium-ion transport is studied using EIS.