Theoretical insights into interfacial stability and ionic transport of Li₂OHBr solid electrolyte for all-solid-state...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Li-rich antiperovskites are explored as inorganic solid electrolytes (ISEs) for all-solid-state Li-ion batteries (ASSLIBs).
• Challenges include phase stability, electrochemical stability, and understanding Li-ion transport mechanisms.

Purpose of the Study:

• Investigate phase stability, interfacial stability, defect chemistry, and transport properties of Li₂OHBr using first-principles calculations.
• Assess Li₂OHBr as a potential inorganic solid electrolyte for ASSLIBs.

Main Methods:

• First-principles computational studies.
• Analysis of thermodynamic metastability, electrochemical stability window, chemical stability with cathode materials and moisture.
• Identification of dominant defects and calculation of Li-ion migration barriers.

Main Results:

• Li₂OHBr is thermodynamically metastable and experimentally synthesizable.
• Exhibits a wide electrochemical stability window (0.80-3.15 V) and good chemical stability.
• Dominant defects V_Li and Li_i⁺ yield low migration barriers (0.38 and 0.49 eV).
• Fluorine substitution effectively reduces migration barriers.

Conclusions:

• Li₂OHBr is a promising candidate for inorganic solid electrolytes.
• Computational insights guide the design of high-performance solid electrolytes for all-solid-state Li-ion batteries.