Size effect of SO₂ receptors on the energy efficiency of Na-SO₂ batteries: gallium-based inorganic electrolytes

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.