Publication: A microstructure-resolved model of sodium-ion battery hard carbon electrodes

To improve the design and accelerate the adoption of Sodium-Ion Batteries (SIBs), it is necessary to improve our understanding of the electrochemical behavior of Hard Carbon (HC) negative electrodes. We report here a novel electrochemical model that unravels the sodiation mechanism of HC electrodes. This model considers the explicit 3D-resolved HC electrode microstructure at the mesoscale, operating in a half cell versus sodium metal. We have parameterized and validated this model using structural (particle shape and size, skeletal density, and textural properties) and electrochemical (cycling protocol, experimental capacity, and discharge profile) characterizations of a specific HC material. Then, we used the model to investigate how manufacturing parameters (formulation and porosity) affect the 3D-resolved sodiation heterogeneities, impacting the electrochemical performance at different C-rates. Our model represents the first approach to create a flexible computational tool for researchers and engineers to assess the kinetic and transport limitations of their specific HC material. Furthermore, it can help them understand the underlying sodiation phenomena taking place in their material via direct comparison with their galvanostatic profiles, while considering the sodiation heterogeneities arising from the electrode's 3D microstructure, supporting the ramp-up in the production of SIBs.

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