Li₇La₃Zr₂O₁₂ (LLZO) has excellent electrochemical performance and chemical stability, and has a promising application in solid-state batteries. However, the ionic conductivity needs to be improved when comparing with liquid electrolytes. And doping is a common strategy to improve the ionic conductivity. In this paper, investigated the optimal doping conditions and calcination temperature for the synthesis of Li_7-3x-yAl_xLa₃Zr_2-yM_yO₁₂(M = Ta,Nb;x = 0.2–0.3;y = 0–1) by high-temperature solid-phase method, and the effects of AlTa and AlNb co-doping modification on the crystal structure, morphology, densification, and electrical properties of LLZO. The results show that Ta and Nb doping between 0.4 and 0.8 can be synthesized garnet-type LLZO solid electrolytes with stable cubic phase. The calcination temperature and time of AlTa co-doping is 950 °C and >8 h, AlNb co-doping is 900 °C and >6 h. Among them, the electrolyte made of AlNb co-doping is better than AlTa co-doping in terms of morphology and densification, and the highest ionic conductivity of both of them can reach up to 8.483 × 10⁻⁴ S·cm⁻¹ and 7.928 × 10⁻⁴ S·cm⁻¹, respectively, and activation energies can reduce to 0.298 eV and 0.301 eV, which are a significant enhancement of the electrical properties. However, the oxides of Nb element are cheaper, and the calcination synthesis temperature is lower and the time is shorter. Therefore, the synthesis of AlNb co-doped modified LLZO by high-temperature solid-phase method is a low-cost, low energy consumption and high performance industrial production routes.

Li ₇ La ₃ Zr ₂ O ₁₂ (LLZO)具有优异的电化学性能和化学稳定性，在固态电池中具有广阔的应用前景。然而，与液体电解质相比，离子电导率还有待提高。掺杂是提高离子电导率的常用策略。本文研究了合成Li _7-3x-y Al _x La ₃ Zr _2-y M _y O ₁₂ (M = Ta,Nb;x = 0.2–0.3;y = 0 –1) 采用高温固相法，研究了Al Ta和Al Nb共掺杂改性对LLZO晶体结构、形貌、致密化和电性能的影响。结果表明，Ta、Nb掺杂量在0.4~0.8之间可以合成稳定立方相的石榴石型LLZO固​​体电解质。Al Ta共掺杂的焙烧温度和时间为950℃且>8h，AlNb共掺杂为900℃且>6h。其中，Al Nb共掺杂制成的电解质在形貌和致密化方面优于Al Ta共掺杂，两者的最高离子电导率均可达到8.483×10 -4 ^S  ·cm ^-1分别为7.928×10 ^-4  S·cm ^{-1和7.928×10 -4 S·cm -1} ，活化能可降低至0.298 eV和0.301 eV，电性能显着增强。但Nb元素的氧化物较便宜，且煅烧合成温度较低、时间较短。因此，高温固相法合成AlNb共掺杂改性LLZO是一条低成本、低能耗、高性能的工业化生产路线。