Tailoring Crucible Surfaces for Suppressing Volatile Element Loss

For ceramic solid electrolytes with volatile elements (lithium, sodium, etc.), it is difficult to precisely control the composition after sintering, leading to low ionic conductivity. Herein, we design a special crucible that can suppress Li loss for sintering high-quality Ta-doped Li 7 La 3 Zr 2 O 12 (LLZTO) ceramics without using mother powder. The photopolymerization three-dimensional (3D) printed Al 2 O 3 crucible, offering manufacturing flexibility in size and shape, undergoes gas–solid reactive sintering to form a dense LiAlO 2 layer on its surface that suppresses lithium loss by preventing lithium from reacting with the crucible. Interestingly, the LiAlO 2 layer indicates a large average grain size of 30.2 μm and ⟨111⟩ crystallographic orientation. The LLZTO ceramics sintered in this Al 2 O 3 @LiAlO 2 crucible exhibit higher ionic conductivity than those sintered in a traditional Al 2 O 3 crucible. Furthermore, the Al 2 O 3 @LiAlO 2 crucible is reusable, significantly reducing the preparation costs. This method can be extended to the preparation of other materials prone to element loss at high temperatures.