2.2. Preparation of an LATP-xSn Ceramic Solid Electrolyte

The Sn-doped Li_1.3Al_0.3Sn_xTi_1.7−x(PO₄)₃ (LATP-xSn, x = 0–0.4) solid electrolyte was prepared by a solid-phase reaction method. The stoichiometric quantities of raw materials for preparing an LATP-xSn ceramic solid electrolyte are as follows: LiNO₃ (1.3), Al₂O₃ (0.3), SnO₂ (x, where x = 0, 0.1, 0.2, 0.3, 0.35, 0.4), TiO₂ (1.7 − x), and NH₄H₂PO₄ (3) are mixed evenly in a ceramic mortar. Then, the powder mixture was calcined in an alumina crucible at 300 °C for 3 h. The temperature was then programmatically increased to 700 °C (5 °C/min) and held for 5 h. After cooling and grinding, the samples were pressed at 16 MPa for 10 min into wafers with a diameter of 13 mm and a thickness of 1.5–2.5 mm. Finally, the green-pressing wafers were sintered at 900 °C for 6 h.