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 Li7La3Zr2O12 (LLZTO) ceramics without using mother powder. The photopolymerization three-dimensional (3D) printed Al2O3 crucible, offering manufacturing flexibility in size and shape, undergoes gas–solid reactive sintering to form a dense LiAlO2 layer on its surface that suppresses lithium loss by preventing lithium from reacting with the crucible. Interestingly, the LiAlO2 layer indicates a large average grain size of 30.2 μm and ⟨111⟩ crystallographic orientation. The LLZTO ceramics sintered in this Al2O3@LiAlO2 crucible exhibit higher ionic conductivity than those sintered in a traditional Al2O3 crucible. Furthermore, the Al2O3@LiAlO2 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.