NMR spectroscopy of solid-state battery electrolytes have been used to measure the diffusion constant and its temperature dependence . The diffusion constant is intrinsically linked to the ionic conductivity of the solid-state electrolyte through the Nernst-Einstein equation . Puled field gradient (PFG) NMR allows for direct measurement of the Li diffusion constant . However, due to small values of the diffusion constant and the short Li spin-spin relaxation time, measurements of the Li diffusion in solid-state electrolytes typically requires specialized PFG probes with gradient strength > 10 T/m . Alternatively, the Bloembergen-Bloom-Purcell (BPP) model for the dipolar interaction between two Li nuclei is used to relate the NMR relaxation rates with the correlation time of interaction between two lithium ions. The correlation time is then used to estimate Li diffusion constant through the Einstein-Smoluchowski equation .