Li₇La₃Zr₂O₁₂ (LLZO) garnet is one of the most promising Li-ion solid electrolytes for all-solid-state Li-ion batteries, owing to its high chemical stability against Li metal and relatively high Li-ion conductivity. In order to further enhance the conductivity of LLZO, Gd³⁺ is used to dope LLZO at the Zr⁴⁺ site, in order to enable excess Li to occupy the octahedral sites, which could facilitate Li-ion transport and increase ionic conductivity. In this study, Li_7+xLa₃Zr_2-xGd_xO₁₂ (LLZGO, x = 0–0.5) solid electrolytes with cubic phase and high relative densities are prepared at 1220 °C using a solid-state reaction method. It is found that LLZGO garnets with x from 0.1 to 0.2 deliver higher conductivities than pristine LLZO. Among these, the Li_7.2La₃Zr_1.8Gd_0.2O₁₂ (LLZG2O) sample achieves the highest room-temperature total conductivity of 2.3 × 10⁻⁴ S cm⁻¹. X-ray diffraction characterization confirms that LLZG2O is chemically stable against Li metal at room temperature for half a month. Cyclic voltammetry shows that LLZG2O possesses good electrochemical stability and reversibility of Li dissolution and deposition reactions. Symmetrical cells using a LLZG2O solid electrolyte and two Li metal electrodes are cycled galvanostatically under various current densities. The results demonstrate that the cell can achieve excellent cycling stability and low overpotentials for the dissolution and deposition reactions of Li. The substitution of Gd³⁺ for Zr⁴⁺ is effective in improving the Li-ion conductivity of LLZO, and Li_7+xLa₃Zr_2-xGd_xO₁₂ could be promising as solid electrolytes for high-performance all-solid-state Li-ion batteries.

Li ₇ La ₃ Zr ₂ O ₁₂（LLZO）石榴石是全固态锂离子电池最有前途的锂离子固体电解质之一，因为它对锂金属的化学稳定性高且锂离子电导率相对较高。为了进一步提高LLZO的电导率，Gd ³⁺用于在Zr ⁴⁺位点掺杂LLZO，以使过量的Li占据八面体位点，这可以促进Li离子的传输并增加离子电导率。在这项研究中，Li _{7 + x} La ₃ Zr _2-x Gd _x O ₁₂（LLZGO，x = 0-0.5）使用固态反应方法在1220°C下制备具有立方相和高相对密度的固体电解质。发现x的0.1至0.2的LLZGO石榴石比原始的LLZO具有更高的电导率。其中，Li _7.2 La ₃ Zr _1.8 Gd _0.2 O ₁₂（LLZG2O）样品的室温总电导率最高，为2.3×10 ^-4  S cm ^-1。X射线衍射表征证实LLZG2O在室温下对锂金属化学稳定半个月。循环伏安法表明，LLZG2O具有良好的电化学稳定性和锂溶解和沉积反应的可逆性。使用LLZG2O固体电解质和两个锂金属电极的对称电池在各种电流密度下恒电流循环。结果表明，该电池可实现优异的循环稳定性和低的Li溶解和沉积反应超电势。用Gd ³⁺代替Zr ⁴⁺可有效提高LLZO的锂离子电导率，以及Li _{7 + x} La ₃ Zr _2-x Gd _x O作为高性能全固态锂离子电池的固体电解质，₁₂有望成为有前景的产品。