Lithium ion batteries achieve much attention because of their wide applications ranging from portable electronics to transportation and grid storage. The next-generation lithium ion batteries require a highly conducting solid electrolyte which ensures safe operation. Garnet-type oxides with nominal chemical formula, Li₅La₃Ta₂O₁₂ are promising Li⁺ conductors which show high ionic conductivity, low electronic conductivity and electrochemical stability.¹ It is important to understand the fundamental electrical transport mechanism of these garnet-type solid-state Li⁺ conductors with respect to change in temperature and lithium content in the structure. Li⁺ stuffing into Li₅La₃Ta₂O₁₂ have proven to improve the ionic conductivity of garnet-type oxides.² The present study reports highly conducting lithium-stuffed Li_5+2xLa₃Ta_2-xY_xO₁₂ (0.05 ≤ x ≤ 0.75) electrolytes.³ Effect of Y³⁺ and Li⁺ doping in Li₅La₃Ta₂O₁₂ on the structural, morphological and electrical properties are studied in this work. Detailed analysis of crystal structure, and electrical and dielectric properties are also performed, in order to investigate the Li⁺ migration pathways in the crystal structure, using different techniques such as powder X-ray diffraction, solid state ⁷Li MAS NMR, and electrochemical impedance spectroscopy.^3-4 The x = 0.50 and 0.75 members in the series of Li_5+2xLa₃Ta_2-xY_xO₁₂ have exhibited highest conductivity of ~ 10^-4 Scm^-1 at 23 ºC. In addition, their stability in aqueous LiCl solution make them suitable candidate as protective layers for lithium electrodes in lithium-air batteries.³

References

1. Thangadurai, V.; Kaack, H.; Weppner, W. J. F. J. Am. Ceram. Soc. 2003, 86, 437-440.

2. Thangadurai, V.; Narayanan, S., Pinzaru, D. Chem. Soc. Rev. 2014, 43, 4714-4727.

3. Narayanan, S.; Ramezanipour, F.; Thangadurai, V. Inorg. Chem. 2015, 54(14), 6968-6977.

4. Baral, A. K.; Narayanan, S.; Ramezanipour, F.; Thangadurai, V. Phys. Chem. Chem. Phys. 2014, 16, 11356-11365.