Operando neutron radiography validates a parameter-free transport-kinetics model for thick solid-state battery...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Thick composite cathodes are crucial for high-energy solid-state batteries.
• Predicting lithium transport through these complex microstructures is challenging.
• Existing models often require extensive parameter fitting.

Purpose of the Study:

• To develop a parameter-free model for predicting through-thickness lithium gradients in thick composite all-solid-state cathodes.
• To establish transferable design rules for suppressing transport-limited reaction fronts.
• To validate the model using operando neutron radiography.

Main Methods:

• Utilized image-derived microstructures to quantify tortuosity.
• Incorporated concentration-dependent solid diffusion coefficients derived from GITT (Galvanostatic Intermittent Titration Technique).
• Developed tortuosity-weighted interfacial kinetics to model lithium transport.

Main Results:

• The tortuosity-weighted interfacial flux for lithium (TWIF-Li) model accurately predicts lithium gradients.
• The model successfully reproduces operando neutron radiography data across practical charge/discharge rates.
• Demonstrated the transferability of the model and derived design rules.

Conclusions:

• TWIF-Li provides a robust, parameter-free approach for understanding lithium transport in thick composite cathodes.
• The findings offer practical design guidelines for optimizing solid-state battery performance.
• This work advances the development of next-generation solid-state energy storage devices.