We have investigated through AC electrical conductivity and differential scanning calorimetry, the annealing behavior of a disordered (microcrystalline) form of Li2SO4obtained by quenching from its melting point, to 300 °C. Annealing causes structural relaxation of the microcrystalline phase leading to an optimization of Li+conduction path, resulting in a high Li+conductivity with low (0.18 eV) activation energy.