Superionic Conductivity in Sodium Zirconium Chloride‐Based Compounds

Abstract

AbstractAll‐solid‐state sodium batteries are attracting intensive attention, and chloride‐based solid electrolytes are promising candidates for use in such batteries because of their high chemical stability and low Young's modulus. Here, we report new superionic conductors based on polyanion‐added chloride‐based materials. Na0.67Zr(SO4)0.33Cl4 showed a high ionic conductivity of 1.6 mS cm−1 at room temperature. X‐ray diffraction analysis indicated that the highly conducting materials are mainly a mixture of an amorphous phase and Na2ZrCl6. The conductivity might be dominated by the electronegativity of the central atom of the polyanion. Electrochemical measurements reveal that Na0.67Zr(SO4)0.33Cl4 is a sodium ionic conductor and is suitable for use as a solid electrolyte in all‐solid‐state sodium batteries.