Oxygen-Mediated Structural Modulation and Ion Transport in xNa₂O-TaCl₅ Glass Electrolytes

Area of Science:

• Materials Science
• Solid-State Chemistry
• Electrochemistry

Background:

• Understanding structure-property relationships in disordered glass solid electrolytes (SEs) is challenging.
• Limited systematic studies exist on oxygen incorporation's impact on local structure and ion transport in multianion halide SEs.

Purpose of the Study:

• To investigate the effect of varying oxygen content on the local structure and ion transport in amorphous sodium oxychloride SEs.
• To elucidate the mechanisms of oxygen-mediated glass formation and ion transport.

Main Methods:

• Synthesis of amorphous sodium oxychloride SEs with varying compositions (xNa2O-TaCl5).
• Characterization using synchrotron and lab X-ray total scattering, Raman spectroscopy, and ab initio molecular dynamics simulations.

Main Results:

• Identified three distinct conductivity regimes in the sodium oxychloride SEs.
• Achieved a maximum ionic conductivity of 4.1 mS cm-1 at room temperature.
• Observed the formation of Ta-O-Ta bonds and clarified the roles of bridging and nonbridging oxygen species.

Conclusions:

• Oxygen incorporation influences glass formation and ion transport mechanisms in sodium oxychloride SEs.
• Findings provide insights into multianion engineering for designing advanced solid electrolytes.