Lithium Dissolution/Deposition Behavior of Al-Doped Li₇La₃Zr₂O₁₂ Ceramics with Different Grain Sizes

Lithium dissolution/deposition behavior of Al-doped Li 7 La 3 Zr 2 O 12 (LLZ) was investigated in terms of grain size of LLZ-sintered bodies. One LLZ had smaller grain sizes of primarily less than 1 μm (LLZ_SG), and the other one had larger grain sizes of 5–20 μm (LLZ_LG). The total resistance of a Li symmetric cell using LLZ_SG was smaller than that using LLZ_LG at 100°C. The cell using LLZ_SG was stably cycled at 100°C without short-circuiting at a high current density of 1.3 mA cm −2 , while the cell using LLZ_LG was stably cycled at current densities below 0.26 mA cm −2 . Stronger bonding at grain boundaries for LLZ_SG was expected to contribute to the improvement of cyclability.