Zhao, Ying ; Jesus, Luis R. de ; Stein, Peter ; Horrocks, Gregory A. ; Banerjee, Sarbajit ; Xu, Bai-Xiang (2017)
Modeling of phase separation across interconnected electrode particles in lithium-ion batteries.
In: RSC Advances, 7
doi: 10.1039/C7RA07352F
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

Lithium transport and phase separation in and across interconnected electrode particles, are investigated in this paper. It signifies the influential role of particle size variations on battery performance with phase-separating electrodes. In this work, a model is developed, accounting for lithium transport in the particle, phase separation, and interface reaction across particle network. The implementation in 3D is carried out by the B-Spline-based Finite Cell Method for a straight-forward treatment of Cahn–Hilliard equation and a flexible representation of particle geometry. Representative examples based on scanning transmission X-ray microscopy (STXM) images are simulated to discuss the factors that will influence phase separation during non-equilibrium lithiation and delithiation, as well as relaxation towards equilibrium. The simulation reveals that particles with a slight advance during (de-)lithiation at the beginning will strengthen their advance at the expense of neighboring particles, in a fashion of “winner-takes-all”. Moreover, rapid reaction can suppress phase separation, both inside a single particle and across the particle network. Lastly, both particle sizes and size variations in electrodes with phase-separating materials ought to be small to avoid intra- and inter-particle phase separation. This study can serve as a guideline for the design of battery electrodes constituted by phase-separating materials.

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