Zheng Wen, Bi Wanying, Fang Yaobing, Chang Shuya, Yuan Wenhui, Li Li
School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China.
Guangdong Engineering Technology Research Center of Advanced Insulating Coating, South China University of Technology-Zhuhai Institute of Modern Industrial Innovation, Zhuhai 519175, China.
ACS Omega. 2021 Sep 21;6(39):25329-25337. doi: 10.1021/acsomega.1c03140. eCollection 2021 Oct 5.
Based on the advantages of intrinsic safety, flexibility, and good interfacial contact with electrodes, a gel polymer electrolyte (GPE) is a promising electrolyte for lithium-ion batteries, compared with the conventional liquid electrolyte. However, the unstable electrochemical performance and the liquid state in a microscale limit the commercial application of GPE. Herein, we developed a novel gel polymer electrolyte for lithium-ion batteries by blending methyl methacrylate (MMA), -butyl--methyl-piperidinium (PyrTFSI), and lithium salts in a solvent-free procedure, with SiO and LiLaTiO (LLTO) additives. The prepared MMA-PyrTFSI-3 wt % LLTO electrolyte shows the best electrochemical performance and obtains a high ion conductivity of 4.51 × 10 S cm at a temperature of 60 °C. Notably, the electrochemical window could be stable up to 5.0 V vs Li/Li. Moreover, the batteries with the GPE also show excellent electrochemical performance. In the LiFePO/MMA-PyrTFSI-3 wt % LLTO/Li cell, a high initial discharge capacity was achieved 150 mA h g at 0.5C with a Coulombic efficiency over 99% and maintaining a good capacity retention of 90.7% after 100 cycles at 0.5C under 60 °C. In addition, the physical properties of the GPE have been investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) measurements, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetry (TG).
基于本征安全性、柔韧性以及与电极良好的界面接触等优点，与传统液体电解质相比，凝胶聚合物电解质（GPE）是一种很有前景的锂离子电池电解质。然而，其不稳定的电化学性能以及微观尺度下的液态状态限制了GPE的商业应用。在此，我们通过在无溶剂过程中将甲基丙烯酸甲酯（MMA）、-丁基--甲基-哌啶鎓（PyrTFSI）和锂盐与SiO和LiLaTiO（LLTO）添加剂混合，开发了一种新型的锂离子电池凝胶聚合物电解质。制备的MMA-PyrTFSI-3 wt% LLTO电解质表现出最佳的电化学性能，在60°C温度下获得了4.51×10 S cm的高离子电导率。值得注意的是，相对于Li/Li，其电化学窗口在高达5.0 V时仍能保持稳定。此外，采用GPE的电池也表现出优异的电化学性能。在LiFePO/MMA-PyrTFSI-3 wt% LLTO/Li电池中，在60°C下0.5C时初始放电容量高达150 mA h g，库仑效率超过99%，在0.5C下100次循环后容量保持率良好，为90.7%。此外，还通过扫描电子显微镜（SEM）、X射线衍射（XRD）测量、傅里叶变换红外（FTIR）光谱和热重分析（TG）对GPE的物理性质进行了研究。
