On-surface lithium donor reaction enables decarbonated lithium garnets and compatible interfaces within cathodes.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Lithium garnets are promising electrolytes for all-solid-state lithium batteries.
• Surface reactions with atmospheric moisture and CO2 form insulating lithium carbonate, degrading battery interfaces.

Purpose of the Study:

• To develop a scalable method for decarbonation of Li6.4La3Zr1.4Ta0.6O12 (LLZTO).
• To create a stable, high-performance composite electrolyte for solid-state lithium batteries.

Main Methods:

• A scalable solid sintering method utilizing a lithium donor reaction.
• Complete decarbonation of LLZTO and formation of an active LiCoO2 layer on garnet particles.
• Synthesis of a LiCoO2-LLZTO@LiCoO2 composite material.

Main Results:

• The LiCoO2-coated LLZTO composite is stable in air, preventing Li2CO3 formation.
• The composite cathode maintained 81% of its initial capacity after 180 cycles at 0.1 C.
• CO2 evolution above 4.0 V was eliminated by transforming Li2CO3 into LiCoO2.

Conclusions:

• The developed method effectively prevents lithium carbonate formation, a key challenge in lithium garnets.
• The LiCoO2-LLZTO@LiCoO2 composite demonstrates improved stability and electrochemical performance.
• This strategy offers a pathway to overcome interfacial issues and advance solid-state battery technology.