Fig. 1: Synthesis and properties of the xNa2O2–MCly (M = Hf, Zr and Ta) SSEs.
From: A family of dual-anion-based sodium superionic conductors for all-solid-state sodium-ion batteries
a, Lab-based XRD patterns of xNa2O2–HfCl4 (0.8 ≤ x ≤ 1.2) and Na2HfCl6 SSEs synthesized employing an identical methodology. The crystalline impurity phase of NaCl is marked with asterisks. 2θ, the angle between the incident beam and diffracted beam. b, The temperature (T )-dependent ionic conductivities (σ) of the as-prepared xNa2O2–HfCl4 (0.8 ≤ x ≤ 1.2) SSEs. c–f, Lab-based XRD patterns (c and d) and Nyquist plots of the EIS measurement results (e and f) of NTOC and NZOC SSEs at 25 °C. Z′ represents the real part of the impedance, and Z″ represents the imaginary part of the impedance. g, Comparison of the ionic conductivity at 25 °C and activation energy (Ea) for the amorphous NMOC SSEs. h, Electrochemical stability windows of NMOC SSEs in comparison with that of the Na3PS4 electrolyte17.
