(a), (b) Electrochemical performances of Na_0.66[Mn_0.66Ti_0.34]O₂/NaTi₂(PO₄)₃ full cell in different aqueous electrolytes (NaSiWE: 2 M NaCF₃SO₃, NaWiSE: 9.26 M NaCF₃SO₃, and 1 M Na₂SO₄). (a) Coulombic efficiency at low rate. (b) Cycle life at high rate.^[46] (c) DSC data, recorded under Ar at 10 °C/min, of Na₃Zr₂Si₂PO₁₂ (top) and Na₃V₂(PO4)₃ (down).^[49] (d) TGA results for the composite solid film, ether-based liquid electrolyte (1 M NaCF₃SO₃/TEGDME), and NASICON-based composite hybrid solid electrolyte (HSE). (e) Shrinkage of commercial membrane (Celgard) and HSE at 120 °C.^[50] (f), (g) Characterization of the neat PEO and as-prepared PEO₂₀NaFSI + x wt.% Al₂O₃ (x = 0, 1, 2) blended polymer electrolyte: (f) TGA traces from 30 °C to 600 °C (the inset is an enlarged image from 30 °C to 200 °C); (g) typical charge and discharge curves of Na₃V₂(PO₄)₃ half-cells at the 1 C rate at 80 °C. (AQ: aqueous process; AN: acetonitrile as solvent).^[51]