Dendrite-separator interactions in lithium-based batteries

The effect of separator pore size on lithium dendrite growth is assessed through the use of the phase field method (PFM). Dendrites are found to undergo concurrent electrodeposition and electrodissolution that define their local growth or shrinkage. Moreover, dendrites are observed to detach due to...

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Bibliographic Details
Published in:Journal of power sources 2015-02, Vol.275, p.912-921
Main Authors: Jana, Aniruddha, Ely, David R., García, R. Edwin
Format: Article
Language:English
Subjects:
Channels
Critical current density
Dendrite
Dendritic structure
Electrodissolution
Lithium
Lithium-batteries
Pore size
Porosity
Safety
Separator
Separators
Short circuits
Shrinkage
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Summary:The effect of separator pore size on lithium dendrite growth is assessed through the use of the phase field method (PFM). Dendrites are found to undergo concurrent electrodeposition and electrodissolution that define their local growth or shrinkage. Moreover, dendrites are observed to detach due to localized electrodissolution and generate metallic debris that is detrimental to battery performance. A critical current density exists below which dendrites are fully suppressed. An analytical model based on the performed PFM simulations allows to formulate the critical current density as a function of separator morphology and pore radius. Four distinct regimes of dendrite growth are identified: (i) the suppression regime, where dendrite growth is thermodynamically unfavorable; (ii) the permeable regime, where dendrite growth is prohibited beyond the first layer of the separator; (iii) the penetration regime, in which dendrites are stable within the channels of the separator; and (iv) the short circuit regime, where dendrites penetrate the entire width of the separator causing a short circuit. The identification of these regimes serve as a guideline to design improved separators. [Display omitted] •A critical current density exists below which dendritic growth is fully suppressed.•Recharge conditions that favor dendrite detachment and “dead lithium,” are proposed.•The suppression, permeable, penetration, and short circuit regimes are identified.•A map as a function of morphology and C-rate to design safe separators is proposed.
ISSN:0378-7753
1873-2755
DOI:10.1016/j.jpowsour.2014.11.056