Oriented Attachment Strategy Toward Enhancing Ionic Conductivity in Garnet-Type Electrolytes for Solid-State Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Solid-state lithium batteries (SSLBs) offer high energy density and stability but suffer from low ionic conductivity and density in solid-state electrolytes (SSEs).
• Conventional preparation methods for garnet-type SSEs like Li6.5La3Zr1.5Ta0.5O12 (LLZTO) limit their practical application due to insufficient room-temperature performance.
• Addressing these limitations is crucial for advancing SSLB technology.

Purpose of the Study:

• To enhance the Li-ion conductivity and density of garnet-type SSEs for improved SSLB performance.
• To investigate the effect of introducing La2O3 nanoparticles on the microstructure and ion transport properties of LLZTO.
• To demonstrate the potential of the developed SSE in practical SSLB devices.

Main Methods:

• An oriented attachment strategy was employed using La2O3 nanoparticles to modify the ZrO2(Ta2O5) matrix in LLZTO.
• The synthesis involved controlled doping with 10 wt% La2O3 to promote epitaxial growth and create continuous Li-ion transport pathways.
• Characterization included ionic conductivity measurements, density analysis, and electrochemical cycling performance evaluation of SSLBs with LiFePO4 cathodes.

Main Results:

• The addition of La2O3 nanoparticles facilitated oriented attachment and epitaxial growth, leading to a densified interface with 97.3% relative density.
• The optimized SSE achieved a maximum Li-ion conductivity of 8.20 × 10^-4 S·cm^-1 at room temperature.
• SSLBs utilizing the enhanced SSE demonstrated stable cycling with a discharge capacity of 123.1 mA·h·g^-1 and 99.2% Coulombic efficiency after 300 cycles at 0.5C.

Conclusions:

• The oriented attachment strategy with La2O3 nanoparticles effectively enhances the ionic conductivity and density of garnet-type SSEs.
• This approach provides a feasible route to high-performance SSEs for practical solid-state lithium batteries.
• The results indicate significant progress towards overcoming key challenges in SSLB development.