Nonequilibrium Electrochemical Phase Maps: Beyond Butler-Volmer Kinetics

Area of Science:

• Electrochemistry
• Materials Science
• Computational Modeling

Background:

• Accurate electrochemical kinetic models are vital for high-rate energy storage devices.
• Electrode phase transformations are often simplified to equilibrium conditions, not reflecting real-world, finite-rate operation.
• Integrating nonlinear electrochemical kinetics with thermodynamics under nonequilibrium conditions is complex.

Purpose of the Study:

• To develop a computational tool for efficient numerical inversion of rate relationships for general electrochemical kinetic models.
• To enable the creation of nonequilibrium phase maps for electrode materials.
• To analyze the impact of various assumptions and parameters on high-rate phase behavior.

Main Methods:

• Development of a novel software package for numerical inversion of rate relationships.
• Integration of nonlinear electrochemical kinetic models with thermodynamic models.
• Application to general kinetic models, including Marcus-Hush-Chidsey, requiring integral computation.

Main Results:

• Demonstrated the capability to build nonequilibrium phase maps for electrode materials.
• Showcased the software's efficiency in handling complex kinetic models.
• Highlighted that critical current can differ by over a factor of 2 between kinetic models even with fixed parameters.

Conclusions:

• The developed software package facilitates accurate modeling of nonequilibrium phase transformations in energy storage systems.
• Understanding kinetic model influence is critical for predicting high-rate electrode behavior.
• This work provides a pathway for more realistic simulations of electrochemical devices.