Li Ion Dynamics in a LiAlO2 Single Crystal Studied by 7Li NMR Spectroscopy and Conductivity Measurements

Abstract

Dynamics of lithium ions in solid materials is a key parameter for applications such as electrode materials for lithium ion batteries. The Li diffusion in single crystalline γ-LiAlO2 was studied with temperature-dependent 7Li NMR spectroscopy and conductivity measurements. The NMR measurements include a detailed study of the temperature dependence of static spectra and spin–lattice relaxation rate measurements. A combination of these methods allowed us to study diffusion coefficients over a range of more than seven decades. The range covered was 10–20 to 10–13 m2 s–1 corresponding to jump rates between 100 and 107 s–1. An activation energy of about 1 eV was found. The hopping between crystallographically equivalent Li sites was explicitly verified by coalescence of quadrupole satellites in the NMR spectra.