Rechargeable lithium battery using non-flammable electrolyte based on tetraethylene glycol dimethyl ether and olivine cathodes

We propose lithium metal cells employing LiCF₃SO₃ -tetraethylene glycol dimethy ether (TEGDME) electrolyte solution with LiFePO₄ and LiMn₀.₅Fe₀.₅PO₄ cathodes. The electrolyte is selected due to its non-flammability, herein demonstrated, and considered as a key requirement for application cells employing high energy lithium metal anode. The selected olivine cathodes, i.e., stable materials prepared by solvothermal pathway, have regular submicrometrical morphology suitable for cell operation and homogeneous composition, as confirmed by electron microscopy and energy dispersive X-ray spectroscopy. The electrochemical tests reveal promising cycling performances in terms of delivered capacity, stability and rate capability. The Li/LiCF₃SO₃-TEGDME/LiFePO₄ cell operates at 3.5 V with capacity ranging from 150 mAh g⁻¹ at C/10 to 110 mAh g⁻¹ at 2C, while the Li/LiCF₃SO₃-TEGDME/LiFe₀.₅Mn₀.₅PO₄ cell performs following two plateaus at 4.1 V and 3.5 V with capacity ranging from 160 mAh g⁻¹ at C/10 to 75 mAh g⁻¹ at 2C. Hence, the results demonstrate the suitability of TEGDME-based electrolytes in combination with LiFePO₄ and LiFe₀.₅Mn₀.₅PO₄ cathodes for high performances lithium battery