Solvent-Free Procedure to Prepare Ion Liquid-Immobilized Gel Polymer Electrolytes Containing LiLaTiO with High Performance for Lithium-Ion Batteries.

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).