Physikalisch-Chemisches Institut & Zentrum für Materialforschung (ZfM/LaMa) , Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring 17 , 35392 Gießen , Germany.
Heinz Maier-Leibnitz Zentrum (MLZ) , Technische Universität München , Lichtenbergstrasse 1 , 85748 Garching , Germany.
ACS Appl Mater Interfaces. 2018 Apr 4;10(13):10935-10944. doi: 10.1021/acsami.8b00842. Epub 2018 Mar 21.
LiAl Ge(PO) (LAGP) is a solid lithium-ion conductor belonging to the NASICON family, representing the solid solution of LiGe(PO) and AlPO. The typical syntheses of LAGP either involve high-temperature melt-quenching, which is complicated and expensive, or a sol-gel process requiring costly organic germanium precursors. In this work, we report a simple method based on aqueous solutions without the need of ethoxide precursors. Using synchrotron and neutron diffraction, the crystal structure, the occupancies for Al and Ge, and the distribution of lithium were determined. Substitution of germanium by aluminum allows for an increased Li incorporation in the material and the actual Li content in the sample increases with the nominal Li content and a solubility limit is observed for higher aluminum content. By means of impedance spectroscopy, an increase in the ionic conductivity with increasing lithium content is observed. Whereas the lithium ionic conductivity improves, due to the increasing carrier density, the bulk activation energy increases. This correlation suggests that changes in the transport mechanism and correlated motion may be at play in the LiAl Ge(PO) solid solution.
锂铝锗磷酸盐（LAGP）是一种属于 NASICON 家族的固体锂离子导体，代表着 LiGe(PO) 和 AlPO 的固溶体。LAGP 的典型合成方法要么涉及高温熔体淬火，过程复杂且昂贵，要么涉及需要昂贵有机锗前体的溶胶-凝胶工艺。在这项工作中，我们报告了一种基于水溶液的简单方法，无需使用乙氧基前体。通过同步辐射和中子衍射，确定了晶体结构、Al 和 Ge 的占有率以及锂的分布。铝取代锗允许在材料中增加锂的掺入，并且实际的锂含量随标称锂含量的增加而增加，并观察到较高的铝含量存在溶解度极限。通过阻抗谱法，观察到锂离子电导率随锂含量的增加而增加。尽管由于载流子密度的增加，锂离子电导率提高，但体激活能增加。这种相关性表明，在 LiAl Ge(PO) 固溶体中可能存在传输机制和相关运动的变化。
