Na–SO2 batteries have garnered significant attention as alternative energy conversion/storage systems, however, their low energy efficiency, which corresponds to large polarization, is a crucial restriction in achieving high performance of the cell. Here, a new Ga-based inorganic electrolyte, NaGaCl4·2SO2, which effectively improves the energy efficiency by decreasing the coulombic interaction between the ionic species of NaGaCl4 and SO2 is proposed and its underlying working mechanism is demonstrated.
