Diffusion of8Li short-lived radiotracer in Li ionic conductors of NaTl-type intermetallic compounds

Abstract

Non-destructive and on-line Li diffusion experiments in Li ionic conductors are conducted using the short-lived a-emitting radiotracer of 8Li. The radiotracers produced as an energetic and pulsed ion beam from TRIAC (Tokai Radioactive Ion Accelerator Complex) are implanted into a structural defect mediated Li ionic conductor of NaTl-type intermetallic compounds (β-LiGa and β-LiIn). The experimental time spectra of the yields of a-particles are compared with simulated results and Li diffusion coefficients in the intermetallic compounds are extracted with an accuracy of ±10%. The diffusion coefficients obtained for β-LiGa with Li content of 43-54 at.% are discussed in terms of the interaction between Li-ion and the structural defects in the specimen, compared with the cases of β-LiAl and β-LiIn. The nonlinear Li-content dependency of Li diffusion coefficients for β-LiGa suggests that the Li diffusion with the Li-deficient region is obstructed by the defect complex composed of vacancies at the Li sites.