2 research outputs found
Correlating Transport and Structural Properties in Li<sub>1+<i>x</i></sub>Al<sub><i>x</i></sub>Ge<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>3</sub> (LAGP) Prepared from Aqueous Solution
Li<sub>1+<i>x</i></sub>Al<sub><i>x</i></sub>Ge<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>3</sub> (LAGP) is a solid lithium-ion
conductor belonging to the NASICON
family, representing the solid solution of LiGe<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> and AlPO<sub>4</sub>. 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<sup>+</sup> incorporation
in the material and the actual Li<sup>+</sup> content in the sample
increases with the nominal Li<sup>+</sup> 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 Li<sub>1+<i>x</i></sub>Al<sub><i>x</i></sub>Ge<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>3</sub> solid solution
Correlating Transport and Structural Properties in Li<sub>1+<i>x</i></sub>Al<sub><i>x</i></sub>Ge<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>3</sub> (LAGP) Prepared from Aqueous Solution
Li<sub>1+<i>x</i></sub>Al<sub><i>x</i></sub>Ge<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>3</sub> (LAGP) is a solid lithium-ion
conductor belonging to the NASICON
family, representing the solid solution of LiGe<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> and AlPO<sub>4</sub>. 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<sup>+</sup> incorporation
in the material and the actual Li<sup>+</sup> content in the sample
increases with the nominal Li<sup>+</sup> 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 Li<sub>1+<i>x</i></sub>Al<sub><i>x</i></sub>Ge<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>3</sub> solid solution