Diffusion measurements for Li were carried out using a double-stimulated echo pulsed field gradient (PFG) NMR pulse program to suppress convection effects. The experiments were carried out on a 300 MHz Bruker Avance III NMR spectrometer and using a Bruker Diff50 probe. Gradient strengths were arrayed with 16 values for each experiment and the maximum gradient strength and diffusion time were optimised in each case. The 7 Li gradient pulse length (δ) was 2 ms and diffusion time (Δ) was in the range of 20 to 100 ms as required for observation of the signal attenuation. The number of scans was also varied to obtain an acceptable noise-signal ratio. The diffusion data were fitted to the Stejskal-Tanner equation using a non-linear least-squares method within the Bruker TopSpin 4.3.0 software.