Tracer diffusion coefficients measurements on LaPO4-dispersed LATP by means of neutron radiography

Lithium tracer diffusion coefficients have been measured in Li1.3Al0.3Ti1.7(PO4)3 (LATP) and LATP – LaPO4 composite solid electrolytes in the temperature range between 300 °C and 500 °C by means of neutron radiography technique that utilizes the difference in neutron attenuation of 6Li and 7Li isotopes. The diffusion coefficient of LATP – LaPO4 composite is higher than that of pristine LATP, although the difference is much smaller than that estimated from the room temperature conductivity. This suggests that the bulk diffusion becomes the predominant diffusion mechanism at 300 °C to 500 °C instead of the diffusion along the space charge layer formed around the LaPO4 dispersants. •Tracer diffusion experiments were performed for LATP and composite electrolytes.•Higher diffusion coefficient is obtained for composite rather than pristine LATP.•Bulk diffusion is predominant rather than space charge layer diffusion above 300 °C.