Preparation and characterization of Na₃BO₃–Na₂SO₄ glass electrolytes with Na⁺ ion conductivity prepared by a mechanical milling technique

The (100 − x)Na3BO3·xNa2SO4 (0 ≤ x (mol%) ≤ 50) glasses were prepared by mechanical milling. Halo patterns were observed in the compositions 0 ≤ x ≤ 50 by XRD measurements. The Raman spectra indicated that all the glasses were composed of BO33− anions, SO42− anions and Na+ cations. The (100 − x)Na3BO3·xNa2SO4 glasses showed good deformation properties and a dense pellet was prepared by cold-press. The conductivities of the glasses increased with increasing Na2SO4 content, and the 50Na3BO3·50Na2SO4 glass showed the highest conductivity of 5.9 × 10−8 S cm−1 at 25 °C.