| Autor: |
PADARTI, Jeevan kumar, Hisao SUZUKI, Takahiko KAWAGUCHI, Naonori SAKAMOTO, Naoki WAKIYA, Shigeto HIRAI, Tomoya OHNO |
| Zdroj: |
Journal of the Japan Society of Powder & Powder Metallurgy / Funtai Oyobi Fummatsu Yakin; 2024, Vol. 71 Issue 8, p309-315, 7p |
| Abstrakt: |
This study investigated the viability of Hf and/or W doping in Li7La3Zr2O12 (LLZO) through an alkoxide derived sol-gel process aimed at stabilizing the ion-conductive cubic garnet phase. Results revealed that Hf doping tends to favor the tetragonal garnet phase, while co-doping with Hf and W effectively stabilizes the cubic garnet structure. This stabilization is attributed to the similar ionic radii of Hf4+ (0.71 Å) and the slightly smaller W6+ (0.62 Å) compared to Zr4+ (0.72 Å), considering charge neutrality. In both doping scenarios, a coexisting Li-deficient pyrochlore phase is observed, likely due to the use of HfCl4 and WCl6 as starting reagents in the alkoxide process, which results in reduced Li-coordinated carboxyl sites attached to chelated Zr alkoxide. However, increasing the Li excess content above 30% effectively eliminates the pyrochlore phase, thus stabilizing the cubic garnet phase. Impedance measurements conducted on Hf-doped LLZO and Hf,W co-doped LLZO (with 40% excess Li) sintered ceramics reveal a significant enhancement in bulk ion conductivity, with the Hf,W co-doped LLZO pellet exhibiting two orders of magnitude higher conductivity (1.09 × 10−4 S cm−1). This finding confirms the stability of the cubic phase even with partial substitution of W and with 40% excess Li. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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