Diffusion Experiment in Lithium Ionic Conductors with the Radiotracer of 8Li: from Micro- to Nano-diffusion

We have developed a radiotracer method for diffusion studies in lithium ionic conductors, by using, as the tracer, the short-lived α-emitting radioisotope of 8Li from TRIAC (Tokai Radioactive Ion Accelerator Complex). In the method, we measured α-particles coming out of the sample of interest and have found that the time-dependent yields of α-particle from the diffusing 8Li primarily implanted is a good measure of the Li diffusion in the sample. The method has been successfully applied to measure the lithium diffusion coefficients in a typical defect-mediated lithium ionic conductor of LiGa, well demonstrating that the method is very efficient to measure the diffusion in the micro-meter regime per second. Further development, as an extension of the present method, was proposed to measure the diffusion on the nanoscale in lithium ionic conductors.