@article{25304,
  keywords = {Lithium batteries, Pyrrolidinium, Ionic liquid, Lifepo4, Lithium electrode, PEGDME, TEGDME},
  author = {Joon Ho Shin and Pratyay Basak and John B Kerr and Elton J Cairns},
  title = {Rechargeable LiFePO<sub>4</sub> Cells Using N-Methyl-N-butyl pyrrolidinium bis(trifluoromethane sulfonyl)imide-LiTFSI Electrolyte Incorporating Polymer Additives},
  abstract = {<p>We have incorporated polymer additives such as poly(ethylene glycol) dimethyl ether (PEGDME) and tetra(ethylene glycol) dimethyl ether (TEGDME) into <em>N</em>-methyl-<em>N</em>-butylpyrrolidinium bis(trifluoromethane sulfonyl)imide (PYR<sub>14</sub>TFSI)-LiTFSI mixtures. The resulting PYR<sub>14</sub>TFSI + LiTFSI + polymer additive ternary electrolyte exhibited relatively high ionic conductivity as well as remarkably low viscosity over a wide temperature range compared to the PYR<sub>14</sub>TFSI + LiTFSI binary electrolytes. The charge/discharge cyclability of Li/LiFePO<sub>4</sub> cells containing the ternary electrolytes was investigated. We found that Li/PYR<sub>14</sub>TFSI + LiTFSI + PEGDME (or TEGDME)/LiFePO<sub>4</sub> cells containing the two different polymer additives showed very similar discharge capacity behavior, with very stable cyclability at room temperature (RT). Li/PYR<sub>14</sub>TFSI + LiTFSI + TEGDME/LiFePO<sub>4</sub> cells can deliver about 127 mAh/g of LiFePO<sub>4</sub> (74.7% of theoretical capacity) at 0.054 mA/cm<sup>2</sup> (0.2C rate) at RT and about 108 mAh/g of LiFePO<sub>4</sub> (63.4% of theoretical capacity) at 0.023 mA/cm<sup>2</sup> (0.1C rate) at −1 °C for the first discharge. The cell exhibited a capacity fading rate of approximately 0.09-0.15% per cycle over 50 cycles at RT. Consequently, the PYR<sub>14</sub>TFSI + LiTFSI + polymer additive ternary mixture is a promising electrolyte for cells using lithium metal electrodes such as the Li/LiFePO<sub>4</sub> cell reported here. These cells showed the capability of operating over a significant temperature range (~0-~30 °C).</p>},
  year = {2008},
  journal = {Electrochimica Acta},
  volume = {54},
  pages = {410-414},
  month = {12/2008},
  doi = {10.1016/j.electacta.2008.07.062},
  language = {eng},
}