Understanding the Effect of UV-Induced Cross-Linking on the Physicochemical Properties of Highly Performing PEO/LiTFSI-Based Polymer Electrolytes
Understanding the Effect of UV-Induced Cross-Linking on the Physicochemical Properties of Highly Performing PEO/LiTFSI-Based Polymer Electrolytes
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DOI：
10.1021/acs.langmuir.9b00041
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发表时间：
2019-06-25
期刊：
影响因子：
3.9
通讯作者：
Gerbaldi, Claudio
中科院分区：
文献类型：
--
作者：
Falco, Marisa;Simari, Cataldo;Gerbaldi, Claudio
我们报道了一种基于聚环氧乙烷、四（乙二醇）二甲醚（G4）和双（三氟甲烷）磺酰亚胺锂的紫外交联聚合物电解质的结构和传输性质的全面、多技术研究。将交联聚合物电解质的性质与相同组成的非交联样品的性质进行了比较。通过x射线衍射、差示扫描量热法、剪切流变学、Li-7魔角旋转核磁共振（NMR）光谱、F-19和Li-7脉冲场梯度刺激回波核磁共振分析、电化学阻抗谱和傅里叶变换拉曼光谱来评估UV诱导交联对物理/化学特性的影响。综合分析证实，紫外线诱导交联是一种有效的技术，可以抑制聚合物基体的结晶度，减少离子聚集，通过调整聚合物基体的结构/形态特征，在室温下提高Li+输运数（>0.5）和离子电导率（>0.1 mS cm(-1)）。最后，在环境温度下进行的恒流测试中，聚合物电解质允许lifepo4基锂金属电池在0.05或0.1C电流速率下提供满容量，并保持高达1C的高倍率能力，从而实现了数百次稳定的可逆操作。这加强了紫外线诱导交联的作用，实现了优异的电化学特性，开发了一个实用的，易于扩展的过程。
We report a thorough, multitechnique investigation of the structure and transport properties of a UV-cross-linked polymer electrolyte based on poly(ethylene oxide), tetra(ethylene glycol)dimethyl ether (G4), and lithium bis-(trifluoromethane)sulfonimide. The properties of the cross linked polymer electrolyte are compared to those of a non cross-linked sample of same composition. The effect of UV induced cross-linking on the physico/chemical characteristics is evaluated by X-ray diffraction, differential scanning calorimetry, shear rheology, and Li-7 magic angle spinning nuclear magnetic resonance (NMR) spectroscopy, F-19 and Li-7 pulsed field gradient stimulated echo NMR analyses, electrochemical impedance spectroscopy, and Fourier transform Raman spectroscopy. Comprehensive analysis confirms that UV-induced cross-linking is an effective technique to suppress the crystallinity of the polymer matrix and reduce ion aggregation, yielding improved Li+ transport number (>0.5) and ionic conductivity (>0.1 mS cm(-1)) at ambient temperature, by tailoring the structural/morphological characteristics of the polymer matrix. Finally, the polymer electrolyte allows reversible operation with stable profile for hundreds of cycles upon galvanostatic test at ambient temperature of LiFePO4-based lithium-metal cells, which deliver full capacity at 0.05 or 0.1C current rate and keep high rate capabilities up to 1C. This enforces the role of UV-induced cross-linking in achieving excellent electrochemical characteristics, exploiting a practical, easy up-scalable process.