Invited Talks: Transition Metal Oxides - University Blog Service - The ...

The John B. Goodenough Symposium in Materials Science & Engineering –
In Honor of His 90 th Birthday
The University of Texas at Austin, Austin, Texas
October 26-27, 2012
H + ↔Li + Ion-Exchange Chemistry of Ceramic Garnet-Type Electrolytes
Lina Truong and Venkataraman Thangadurai*
University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4
Email: vthangad@ucalgary.ca Website: www.chem.ucalgary.ca/research/groups/vthangad/index.html
Abstract Body in Space Below:
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Chemical stability and ion-exchange of the garnet-type fast Li ion conducting Li 5+x Ba x La 3-x Nb 2 O 12 (x = 0,
0.5, 1) were studied in various media such as water and organic acids. The H + /Li + reaction was found to be
most successful for x = 0, which showed ~89% H + /Li + exchange reaction, while x = 0.5 showed ~46%
and x = 1 showed ~20% in water at room temperature. In Li 5 La 3 Nb 2 O 12 , more of the Li ions occupy the
tetrahedral sites, the ion-exchange reaction occurs readily and to a greater extent. The relative population
of Li ions that reside in the octahedral sites increases with increasing Li content in Li 5+x Ba x La 3-x Nb 2 O 12
and the proton-exchange proceeds to a lesser extent in water. The reaction was also shown to be
reversible, where ionic conductivity of the reverse Li exchanged product from the H-garnet, for x = 0, was
found to show comparable values to its original solid state synthesized Li 5 La 3 Nb 2 O 12 . Similar trends were
found when the H + /Li + ion-exchange reaction was done at room temperature using weak organic acids,
including CH 3 COOH and C 6 H 5 COOH as proton sources. The exchange was almost (100%) completed
using the x = 0 member in CH 3 COOH.