Discovering the Influence of Lithium Loss on Garnet Li 7 La 3 Zr 2 O 12 Electrolyte Phase Stability

作者：Andrea Paolella, Wen Zhu, Giovanni Bertoni, Sylvio Savoie, Zimin Feng, Hendrix Demers, Vincent Gariépy, Gabriel Girard, Etienne Rivard, Nicolas Delaporte, Abdelbast Guerfi, Henning Lorrmann, Chandramohan George, Karim Zaghib · 发表于：ACS Applied Energy Materials · 年份：2020 · DOI：10.1021/acsaem.9b02401 · 被引用次数：91 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Advanced Battery Technologies Research

Garnet-type lithium lanthanum zirconate (Li 7 La 3 Zr 2 O 12, LLZO)-based ceramic electrolyte has potential for further development of all-solid-state energy storage technologies including Li metal batteries as well as Li–S and Li–O 2 chemistries. The essential prerequisites such as LLZO’s compactness, stability, and ionic conductivity for this development are nearly achievable via the solid-state reaction route (SSR) at high temperatures, but it involves a trade-off between LLZO’s caveats because of Li loss via volatilization. For example, SSR between lithium carbonate, lanthanum oxide, and zirconium oxide is typically supplemented by dopants (e.g., gallium or aluminum) to yield the stabilized cubic phase (c-LLZO) that is characterized by ionic conductivity an order of magnitude higher than the other polymorphs of LLZO. While the addition of dopants as phase stabilizing agent and supplying extra Li precursor for compensating Li loss at high temperatures become common practice in the solid-state process of LLZO, the exact role of dopants and stabilization pathway is still poorly understood, which leads to several manufacturing issues. By following LLZO’s chemical phase evolution in relation to Li loss at high temperatures, we here show that stabilized c-LLZO can directly be achieved by an in situ control of lithium loss during SSR and without needing dopants. In light of this, we demonstrate that dopants in the conventional SSR route also play a similar role, i.e., making mor...