Theoretical and Experimental Studies of KLi6TaO6 as a Li-Ion Solid Electrolyte

We study a hexagonal oxide KLi6TaO6 (KLTO), proposed as a Li-ion solid electrolyte, by using a recently developed screening method. First-principles calculations predict that KLTO presents a good Li-ion conductivity (sigma(Li)) and a low activation energy (E-a). Li migration is enhanced by the presence of excess Li ions in the interstitial region via a kick-out mechanism. Our experimental results demonstrate that Sn-doped KLTO presents a conductivity of 1 x 10(-5) S cm(-1), a sigma(Li) of 6 x 10(-6) S cm(-1), and a relatively low Ea of 36 kJ mol(-1), which confirm the validity of the proposed screening method. Conversely, detailed analyses of the microstructure and X-ray diffraction patterns of KLTO samples indicate that a stable Li-excess condition is not achieved, therefore leaving potential improvement of the performance of KLTO as a Li-ion solid electrolyte by optimizing extrinsic doping and fabrication processes.

Automated summary

The study shows that KLTO exhibits good Li-ion conductivity and low activation energy, with Sn-doped KLTO demonstrating superior performance. However, further improvements in extrinsic doping and fabrication processes are necessary to enhance the performance of KLTO as a Li-ion solid electrolyte.