凝胶聚合物电解质(GPE)是当前最具商业化应用前景之一的准固态电解质,可以缓解甚至解决锂离子电池存在的漏液、挥发、燃烧等潜在安全问题。本文通过高温原位固化技术制备了一种以甲基丙烯酸甲酯为单体、聚乙二醇二甲基丙烯酸酯为交联剂...凝胶聚合物电解质(GPE)是当前最具商业化应用前景之一的准固态电解质,可以缓解甚至解决锂离子电池存在的漏液、挥发、燃烧等潜在安全问题。本文通过高温原位固化技术制备了一种以甲基丙烯酸甲酯为单体、聚乙二醇二甲基丙烯酸酯为交联剂、双(氟磺酰)亚胺锂为导电盐、碳酸乙烯酯/碳酸甲乙酯混合溶剂为增塑剂的GPE。通过热重分析对聚甲基丙烯酸甲酯(PMMA)基GPE的热力学性质进行了表征,采用计时安培法和电子扫描显微镜研究了PMMA基GPE对Al集流体的稳定性。研究结果表明,PMMA基GPE在室温拥有较高的电导率,达到6.61 mS/cm,同时可以将碳酸酯电解液的挥发温度由100.3℃提高至138.1℃。PMMA基GPE在高电位下对Al箔显示出良好的稳定性,4.3 V vs.Li/Li+以下不会发生铝箔腐蚀,而且在商用石墨/LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)软包电池中展现出良好的循环稳定性和容量保持能力,循环1000次后容量保持率为93.4%。展开更多
The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, ...The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, with capacity retention of only about 67% after 20 cycles. It is essential to understand the origin of the instability. It is noticed that the polarization voltage and the impedance of the cell both increase slowly upon cycling. The structure and the properties of the pristine and the cycled LiCoO2 cathodes are investigated by x-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, x-ray photoelectron spectroscopy（XPS）, and transmission electron microscopy（TEM）. It is found that the LiCoO2 particles are corroded by this molten salt electrolyte, and the decomposition by-product covers the surface of the LiCoO2 cathode after 20 cycles. Therefore, the surface side reaction explains the instability of the molten salt electrolyte with LiCoO2.展开更多
文摘凝胶聚合物电解质(GPE)是当前最具商业化应用前景之一的准固态电解质,可以缓解甚至解决锂离子电池存在的漏液、挥发、燃烧等潜在安全问题。本文通过高温原位固化技术制备了一种以甲基丙烯酸甲酯为单体、聚乙二醇二甲基丙烯酸酯为交联剂、双(氟磺酰)亚胺锂为导电盐、碳酸乙烯酯/碳酸甲乙酯混合溶剂为增塑剂的GPE。通过热重分析对聚甲基丙烯酸甲酯(PMMA)基GPE的热力学性质进行了表征,采用计时安培法和电子扫描显微镜研究了PMMA基GPE对Al集流体的稳定性。研究结果表明,PMMA基GPE在室温拥有较高的电导率,达到6.61 mS/cm,同时可以将碳酸酯电解液的挥发温度由100.3℃提高至138.1℃。PMMA基GPE在高电位下对Al箔显示出良好的稳定性,4.3 V vs.Li/Li+以下不会发生铝箔腐蚀,而且在商用石墨/LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)软包电池中展现出良好的循环稳定性和容量保持能力,循环1000次后容量保持率为93.4%。
基金Project supported by the Beijing S&T Project,China(Grant No.Z13111000340000)the National Basic Research Program of China(Grant No.2012CB932900)the National Natural Science Foundation of China(Grants Nos.51325206 and 51421002)
文摘The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, with capacity retention of only about 67% after 20 cycles. It is essential to understand the origin of the instability. It is noticed that the polarization voltage and the impedance of the cell both increase slowly upon cycling. The structure and the properties of the pristine and the cycled LiCoO2 cathodes are investigated by x-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, x-ray photoelectron spectroscopy（XPS）, and transmission electron microscopy（TEM）. It is found that the LiCoO2 particles are corroded by this molten salt electrolyte, and the decomposition by-product covers the surface of the LiCoO2 cathode after 20 cycles. Therefore, the surface side reaction explains the instability of the molten salt electrolyte with LiCoO2.
