Influence of lithium bis(oxalato)borate salt on the structure, thermal properties and ionic conductivity of poly(ethylene oxide)

IF 3 3区工程技术 Q2 CHEMISTRY, ANALYTICAL

Journal of Thermal Analysis and Calorimetry Pub Date : 2025-01-21 DOI:10.1007/s10973-024-13960-5

Irena Krešić, Nataša Stipanelov Vrandečić, Matko Erceg, Zoran Grubač, Ante Bilušić

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引用次数: 0

Abstract

Polymer electrolytes based on poly(ethylene oxide) (PEO) and a lithium bis(oxalato)borate salt (LiBOB) have shown their potential for applications as electrolytes for lithium-ion polymer batteries. However, there are not enough studies to clarify the direct impact of LiBOB on the properties of PEO in polymer electrolytes. Therefore, the aim of this study is to clarify the dependence of the addition of the LiBOB salt on the structure, thermal properties and ionic conductivity of PEO. Solid polymer electrolytes with different ether oxygen to lithium ions molar ratios (EO/Li) (PEX) were prepared. Fourier transform infrared spectroscopy (FTIR) analysis showed that the salt concentration has affected the structure of PEO, especially its crystallinity as one of the most important properties affecting the ionic conductivity of PEO-based polymer electrolytes. These results were confirmed by differential scanning calorimetry (DSC) analysis as the degree of crystallinity decreases with the addition of salt. Moreover, DSC analysis revealed the composition of the samples at which crystallinity of PEO completely disappeared. Scanning electron microscopy (SEM) showed the modifications in surface morphological features of PEX as a function of LiBOB concentration. The results obtained from these studies were correlated with the most important result for the application of polymer electrolyte, that of electrochemical impedance spectroscopy (EIS). It revealed the maximum ionic conductivity at room temperature as high as 1.68∙10^–4 S cm^⁻1 for sample with EO/Li molar ratio 5. The importance of this result lies in the promising increase of five orders of magnitude compared to the ionic conductivity of PEO and in reaching the practical applicable ionic conductivity. Furthermore, thermogravimetric analysis (TGA) showed that the addition of salt causes a more complex non-isothermal decomposition of the prepared samples compared to pure PEO.

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硼酸锂对聚环氧乙烷结构、热性能和离子电导率的影响

基于聚环氧乙烷（PEO）和草酸锂硼酸盐（LiBOB）的聚合物电解质已显示出其作为锂离子聚合物电池电解质的应用潜力。然而，目前还没有足够的研究来阐明LiBOB对聚合物电解质中PEO性能的直接影响。因此，本研究的目的是阐明LiBOB盐的加入对PEO结构、热性能和离子电导率的影响。制备了不同乙醚氧与锂离子摩尔比（EO/Li）（PEX）的固体聚合物电解质。傅里叶变换红外光谱（FTIR）分析表明，盐浓度影响了PEO的结构，特别是结晶度是影响PEO基聚合物电解质离子电导率的重要性质之一。差示扫描量热法（DSC）分析证实了这一结果，因为随着盐的加入，结晶度降低。DSC分析表明，样品的结晶度完全消失。扫描电镜（SEM）显示PEX的表面形态特征随LiBOB浓度的变化而变化。这些研究结果与电化学阻抗谱（EIS）这一聚合物电解质应用中最重要的结果相关联。结果表明，EO/Li摩尔比为5的样品在室温下的最大离子电导率高达1.68∙10-4 S cm - 1。该结果的重要性在于与PEO的离子电导率相比有希望提高5个数量级，并达到实际适用的离子电导率。此外，热重分析（TGA）表明，与纯PEO相比，盐的加入使制备的样品的非等温分解更加复杂。

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来源期刊

Journal of Thermal Analysis and Calorimetry 化学-分析化学

CiteScore

8.50

自引率

9.10%

发文量

577

审稿时长

3.8 months

期刊介绍： Journal of Thermal Analysis and Calorimetry is a fully peer reviewed journal publishing high quality papers covering all aspects of thermal analysis, calorimetry, and experimental thermodynamics. The journal publishes regular and special issues in twelve issues every year. The following types of papers are published: Original Research Papers, Short Communications, Reviews, Modern Instruments, Events and Book reviews. The subjects covered are: thermogravimetry, derivative thermogravimetry, differential thermal analysis, thermodilatometry, differential scanning calorimetry of all types, non-scanning calorimetry of all types, thermometry, evolved gas analysis, thermomechanical analysis, emanation thermal analysis, thermal conductivity, multiple techniques, and miscellaneous thermal methods (including the combination of the thermal method with various instrumental techniques), theory and instrumentation for thermal analysis and calorimetry.