Abstract Effect of binary lithium salts (lithium tetrafluoroborate, LiBF4 with lithium trifluoromethanesulfonate, LiCF3SO3) and (lithium tetrafluoroborate, LiBF4 with Lithium iodide, LiI) as charge carriers in solid polymer electrolyte based 49% poly(methyl methacrylate) grafted natural rubber (MG49) for Li-ion battery application has been investigated. The polymer electrolytes were prepared by solution casting technique. The effect of binary lithium salts on chemical interaction, structural, thermal studies, ionic conductivity and ion transference number of MG49 films are analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electrochemical impedance spectroscopy (EIS). Infrared analysis indicated the interaction occurred between Li ions and oxygen atoms at the carbonyl group ( C O) and the ether group (C O C) on methyl methacrylate (MMA) segments. XRD studies exhibited a reduction of the MMA peak intensity at 29.5° after the addition of different ratios of binary Li salts due to the plasticizing effect of the salts. The larger anion size tends to create bigger free volume in the polymer electrolyte. In addition, this confirms that the degree of crystallinity of the electrolyte films is reduced leading to enhancement of ionic conductivity. DSC results revealed the highest conductivity sample has the lowest Tg implying the ions can flow with more ease throughout the polymer chain. The ratios of LiBF4:LiI presenting the higher overall performance in terms of ionic conductivity comparing to LiBF4:LiCF3SO3 ratios in MG49. The highest room temperature conductivity was obtained at 1.89 × 10−6 S cm−1 for (30:70) LiBF4:LiI percentages ratio. Moreover, tion is observed to increase with the ionic conductivities.

中文翻译：

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二元锂盐对 49% 聚甲基丙烯酸甲酯接枝天然橡胶基固体聚合物电解质的影响

摘要 二元锂盐（四氟硼酸锂，LiBF4 与三氟甲磺酸锂，LiCF3SO3）和（四氟硼酸锂，LiBF4 与碘化锂，LiI）作为电荷载流子在基于 49% 聚甲基丙烯酸甲酯接枝天然橡胶 (MG49) 的固体聚合物电解质中的作用对锂离子电池的应用进行了研究。聚合物电解质采用溶液浇铸技术制备。通过傅里叶变换红外 (FTIR) 光谱、X 射线衍射 (XRD)、差示扫描量热法 (DSC) 和分析了二元锂盐对 MG49 薄膜的化学相互作用、结构、热研究、离子电导率和离子转移数的影响。电化学阻抗谱 (EIS)。红外分析表明，锂离子与甲基丙烯酸甲酯 (MMA) 链段上羰基 (CO) 和醚基 (COC) 处的氧原子发生相互作用。由于盐的增塑作用，在加入不同比例的二元锂盐后，XRD 研究表明 MMA 峰强度在 29.5°处降低。较大的阴离子尺寸倾向于在聚合物电解质中产生较大的自由体积。此外，这证实了电解质膜的结晶度降低导致离子电导率提高。DSC 结果显示电导率最高的样品具有最低的 Tg，这意味着离子可以更轻松地在整个聚合物链中流动。与 LiBF4 相比，LiBF4:LiI 的比例在离子电导率方面表现出更高的整体性能：MG49 中的 LiCF3SO3 比率。对于 (30:70) LiBF4:LiI 百分比比，在 1.89 × 10-6 S cm-1 处获得最高室温电导率。此外，观察到 tion 随着离子电导率的增加而增加。