Lithium ion diffusion measurements on a garnet-type solid conductor Li_6.6La₃Zr_1.6Ta_0.4O₁₂ by using a pulsed-gradient spin-echo NMR method

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• 作者：Kikuko Hayamizu^a ; ^{hayamizu.k3@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Yasuaki Matsuda^b ; Masaki Matsui^b ; ^c ; Nobuyuki Imanishi^b
• 关键词：7Li NMR ; Lithium ion diffusion ; Pulsed-gradient spin-echo (PGSE) NMR ; Garnet-type tantalum-doped conductor ; Li6.6La3Zr1.6Ta0.4O12
• 刊名：Solid State Nuclear Magnetic Resonance
• 出版年：2015
• 出版时间：September 2015
• 年：2015
• 卷：70
• 期：Complete
• 页码：21-27
• 全文大小：1275 K

文摘

The garnet-type solid conductor Li_7−xLa₃Zr_2−xTa_xO₁₂ is known to have high ionic conductivity. We synthesized a series of compositions of this conductor and found that cubic Li_6.6La₃Zr_1.6Ta_0.4O₁₂ (LLZO-Ta) has a high ionic conductivity of 3.7×10⁻⁴ Scm⁻¹ at room temperature. The ⁷Li NMR spectrum of LLZO-Ta was composed of narrow and broad components, and the linewidth of the narrow component varied from 0.69 kHz (300 K) to 0.32 kHz (400 K). We carried out lithium ion diffusion measurements using pulsed-field spin-echo (PGSE) NMR spectroscopy and found that echo signals were observed at T  ≥$\ge$313 K with reasonable sensitivity. The lithium diffusion behavior was measured by varying the observation time and pulsed-field gradient (PFG) strength between 313 and 384 K. We found that lithium diffusion depended significantly on the observation time and strength of the PFG, which is quite different from lithium ion diffusion in liquids. It was shown that lithium ion migration in the solid conductor was distributed widely in both time and space.