A solid-state route to stabilize cubic Li₇La₃Zr₂O₁₂ at low temperature for all-solid-state-battery applications

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• High-performance all-solid-state batteries require stable interfaces between solid electrolytes and electrodes.
• Conventional processing of solid electrolytes like cubic Li7La3Zr2O12 garnet often involves high temperatures, increasing manufacturing costs and energy consumption.

Purpose of the Study:

• To develop a low-temperature processing method for cubic Li7La3Zr2O12 garnet.
• To investigate the effect of additives on solid-state reactions and ionic conductivity.
• To enable sustainable production of all-solid-state batteries with reduced thermal budgets.

Main Methods:

• Additive-assisted solid-state reactions utilizing high-energy ball-milling.
• Multistep heating protocols.
• Characterization of Li7La3Zr2O12 garnet structure and ionic conductivity.

Main Results:

• Successfully synthesized cubic Li7La3Zr2O12 garnet at lower processing temperatures.
• Achieved a total Li conductivity of 1.4 × 10-4 S cm-1, comparable to high-temperature processed materials.
• Identified that a lithium borate additive triggers liquid-phase sintering, increasing microstrain and enhancing Li conductivity.

Conclusions:

• Additive-assisted solid-state reactions offer an effective route to lower processing temperatures for Li7La3Zr2O12 garnet.
• The developed method is feasible for sustainable, low-cost production of all-solid-state batteries.
• Understanding additive-induced sintering mechanisms is key to optimizing solid electrolyte performance.