Promoting high-voltage stability through local lattice distortion of halide solid electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Solid-state Chemistry

Background:

• High-voltage lithium batteries require stable solid electrolytes to prevent oxidation and decomposition.
• Current solid electrolytes often fail at high operating voltages, limiting battery performance and safety.
• Halide solid electrolytes face challenges with oxidation and deactivation at elevated charge cut-off voltages.

Purpose of the Study:

• To overcome the high-voltage limitations of halide solid electrolytes.
• To enhance the stability and cycling performance of lithium batteries.
• To explore the application of high-entropy materials in solid-state electrolytes.

Main Methods:

• Introducing local lattice distortion in Li3InCl6 by substituting In with multiple elements.
• Synthesizing a high-entropy halide electrolyte: Li2.75Y0.16Er0.16Yb0.16In0.25Zr0.25Cl6.
• Investigating the effect of lattice distortion on Cl- confinement and Li+ activation.

Main Results:

• The high-entropy electrolyte demonstrated a 250% improvement in cycle stability over 500 cycles.
• Achieved a discharge capacity of 185 mAh g-1 at a high charge cut-off voltage of 4.6 V.
• The modified electrolyte exhibited enhanced stability against oxidation and decomposition at high voltages.

Conclusions:

• Local lattice distortion in high-entropy materials effectively curbs electrolyte oxidation kinetics.
• The developed high-entropy halide electrolyte significantly advances all-solid-state battery performance.
• This work deepens the understanding of high-entropy materials for energy storage applications.