Stability effect of some organic and inorganic additions in the EMITFSI–LiTFSI nanocomposite electrolytes for lithium-air batteries

Since the EMITFSI/LiTFSI electrolyte possess low viscosity, high ionic conductivity and thermal stability properties, in this study, 1M 1-ethyl-3-methyl-imidazoliumbis (trifluoromethanesulfonyl) imide (EMITFSI)/Lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) based electrolytes were studied for Li-air battery cells. A series of electrolytes was studied with organic compound additions of Poly(ethylene oxide) (PEO) and polyvinylidene fluoride (PVDF). Nano Al₂O₃ particles with 50 nm in size were also used in 1.0 wt% as inorganic additive to provide stability of the polymer added electrolytes. The nanocomposite electrolytes were prepared in a glove box under dry argon atmosphere. Porous electrode, Gas Diffusion Layer (GDL), was used as cathode, a lithium disk was used as anode while glass fiber was used as the separator in ECC-air test cell. The cells were cyclically tested using 0.1 mA/cm² current density over a voltage range of 1.5–4.5 V. Electrochemical impedance spectroscopy measurements was applied to investigate the effect of the PVDF/Al₂O₃ and PEO/Al₂O₃ nano additives on the resistivity of the electrolyte. After the electrochemical cycling test, the morphologies of the cathodes (GDL) were analyzed using scanning electron microscopy, X-ray diffraction analysis to determine reaction products and lithium compounds during cycling test.