Diffusion Of Li-8 Short-Lived Radiotracer In Li Ionic Conductors Of Nati-Type Intermetallic Compounds

Non-destructive and on-line Li diffusion experiments in Li ionic conductors are conducted using the short-lived a-emitting radiotracer of Li-8. 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 NaTI-type intermetallic compounds (beta-LiGa and beta-Liln). The experimental time spectra of the yields of (alpha-particies 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 beta-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 P-LiAl and beta-LiIn. The nonlinear Li-content dependency of Li diffusion coefficients for beta-LiGa suggests that the Li diffusion with the Li-deficient region is obstructed by the defect complex composed of vacancies at the Li sites.