摘要： Rechargeable Na/NaFePO₄ cells with a sodium bis(trifluoromethanesulfonyl)imide (NaTFSI)-incorporated butylmethylpyrrolidinium (BMP)–TFSI ionic liquid (IL) electrolyte are demonstrated with an operation voltage of ∼3 V. High-performance NaFePO₄ cathode powder with an olivine crystal structure is prepared by chemical delithiation of LiFePO₄ powder followed by electrochemical sodiation of FePO₄. This IL electrolyte shows high thermal stability (>400 °C) and non-flammability, and is thus ideal for high-safety applications. The effects of NaTFSI concentration (0.1–1.0 M) on cell performance at 25 °C and 50 °C are studied. At 50 °C, an optimal capacity of 125 mA h g⁻¹ (at 0.05 C) is found for NaFePO₄ in a 0.5 M NaTFSI-incorporated IL electrolyte; moreover, 65% of this capacity can be retained when the charge–discharge rate increases to 1 C. This ratio (reflecting the rate capability) is higher than that found in a traditional organic electrolyte. With a 1 M NaTFSI-incorporated IL electrolyte, a 13% cell capacity loss after 100 charge–discharge cycles is measured at 50 °C, compared to the 38% observed in an organic electrolyte under the same conditions. 出版日期： 2014-01-01 出處： Journal of materials chemistry. A, Materials for energy and sustainability, 2014-01, Vol.2 (16), p.5655-5661 資源來源： Royal Society of Chemistry 識別號： ISSN: 2050-7488 識別號： ISSN: 2050-7496 識別號： EISSN: 2050-7496 識別號： DOI: 10.1039/c3ta15273a
