In this report, we study the effect of the addition of fluorine-free 2,2′-bis(4,5-dimethylimidazole) (BDI) on lithium-ion solid polymer electrolytes based on lithium nitrate and poly(methyl methacrylate) (PMMA). Confocal Raman spectroscopy and theoretical Raman calculations were performed to study lithium dissociation and the interaction mechanism of the lithium and nitrate ions with the BDI additive. Additionally, X-ray diffraction analysis showed that the mean coherence length of the PMMA chains is influenced by the BDI concentration. The incorporation of the BDI additive favors the dissociation of lithium salt leading to a maximum enhancement on the lithium conductivity of up to 1.88 × 10⁻⁴ S cm⁻¹ for a critical BDI addition of ∼5% with respect to PMMA, which is very high in comparison with the conductivities of ∼10⁻⁴ S cm⁻¹ usually observed for these solid polymer electrolytes.

中文翻译：

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用于锂离子聚（甲基丙烯酸甲酯）固体聚合物电解质的新型无氟2,2'-双（4,5-二甲基咪唑）添加剂

在本报告中，我们研究了添加无氟2,2'-双（4,5-二甲基咪唑）（BDI）对基于硝酸锂和聚甲基丙烯酸甲酯（PMMA）的锂离子固体聚合物电解质的影响）。进行了共聚焦拉曼光谱和理论拉曼计算，以研究锂的离解以及锂和硝酸根离子与BDI添加剂的相互作用机理。另外，X射线衍射分析表明，PMMA链的平均相干长度受BDI浓度的影响。BDI添加剂的加入有利于锂盐的解离，从而最大程度地提高锂电导率，最高可达1.88×10 ^-4 S cm ^-1对于PMMA而言，临界BDI添加量约为5％，与这些固体聚合物电解质通常观察到的电导率约为10 ^-4 S cm ^-1相比，这是非常高的。