Cocktail Effects in Boosting the Interfacial Ionic Conduction of the Garnet Solid-State Battery

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Garnet-type Li7La3Zr2O12 electrolytes offer nonflammability and high ionic conductivity for solid-state batteries.
• High interfacial resistance and lithium dendrite formation hinder the practical application of garnet solid electrolytes.

Purpose of the Study:

• To develop a 3D composite lithium anode with reduced interfacial resistance and improved lithium-ion transport for garnet solid-state batteries.
• To enhance the interfacial compatibility between lithium metal and garnet electrolytes.

Main Methods:

• Incorporation of carbonized ZIF-8 powder into molten lithium to create a 3D composite anode.
• Density Functional Theory (DFT) calculations to analyze interfacial formation energies.
• Fabrication and testing of symmetric and full solid-state batteries.

Main Results:

• Achieved remarkably low interfacial resistance (15.2 Ω cm²) due to decreased surface tension of molten lithium.
• Identified beneficial interfacial reaction products (Li3N, Li2O, Li-Zn alloy, LiC6) with lower formation energies.
• Demonstrated stable cycling in symmetric cells (350 h at 0.5 mA cm⁻²) and good performance in full cells (LiFePO4 cathode, 86.2% capacity retention).

Conclusions:

• The 3D composite lithium anode effectively suppresses interfacial resistance and dendrite growth.
• Synergistic effects of the composite anode enhance ionic and electronic conductivity, improving battery performance and lifespan.
• This approach offers a viable strategy for developing safe and durable solid-state batteries.