The effect of cubic-phase stabilizing dopant (Al, Ga, Ta) on the mechanical and electrochemical properties of Li garnet solid electrolyte was studied. Dense Li_6.25La₃Al_0.25Zr₂O₁₂, Li_6.50La₃Ta_0.50Zr_1.5O₁₂, Li_6.25La₃Ga_0.25Zr₂O₁₂ were prepared by conventional solid-state synthesis of powder and densified using hot pressing. Ga-LLZO exhibited the highest fracture stress (∼143 MPa), fracture toughness (∼1.22 MPa m^1/2) and total conductivity (∼1 mS/cm) of the three materials; however, the bulk conductivity was about 1.5 mS/cm. We believe that the weak grain-boundaries, as evidenced by a predominately intergranular fracture, correlates with a relatively high grain-boundary impedance, thus reducing the value of the total conductivity by about 30 % lower than that for the bulk. Based on the combined mechanical and electrical properties, overall, Li_6.25La₃Ga_0.25Zr₂O₁₂ exhibits the most favorable combination of some of the most salient properties of the three dopants. We believe the results of this study will facilitate the commercialization of Li metal batteries using Li-garnet ceramic electrolyte.

研究了立方相稳定掺杂剂（Al，Ga，Ta）对锂石榴石固体电解质的力学和电化学性能的影响。通过粉末的常规固态合成来制备致密的Li _6.25 La ₃ Al _0.25 Zr ₂ O ₁₂，Li _6.50 La ₃ Ta _0.50 Zr _1.5 O ₁₂，Li _6.25 La ₃ Ga _0.25 Zr ₂ O ₁₂并使用热压致密化。Ga-LLZO表现出最高的断裂应力（〜143 MPa），断裂韧性（〜1.22 MPa m ^1/2）和三种材料的总电导率（〜1 mS / cm）; 然而，体积电导率约为1.5mS / cm。我们认为，弱的晶界（如主要是晶间断裂所证明）与相对较高的晶界阻抗相关，因此使总电导率值比整体电导率值降低了约30％。基于综合的机械和电学性质，总体上，Li _6.25 La ₃ Ga _0.25 Zr ₂ O ₁₂表现出三种掺杂剂中某些最显着性质的最有利组合。我们相信这项研究的结果将促进使用锂石榴石陶瓷电解质的锂金属电池的商业化。