Forced Reaction Redistribution in High-Loading Lithium-Ion Cathodes
- 1Olivine Energy
Abstract
Classical secondary-current theory predicts a directionally neutral through-thickness reaction distribution when a porous electrode’s effective electronic and ionic conductivities are equal. In a working concentrated electrolyte, the salt-concentration gradient adds a thermodynamic contribution to electrolyte current that shifts this balance. A convention-consistent reduction of the porous-electrode equations shows that, in the quasi-steady weak-depletion onset limit, reaction skew vanishes when the electronic-to-ionic conductivity ratio equals 1/(1+ρe), or 0.390 for the reference electrolyte. Separator-favored reaction therefore persists well below the classical equal-conductivity condition. Full Doyle–Fuller–Newman (DFN) calculations reproduce ∼93% of the predicted boundary displacement across a 2.7-fold change in ρe, although the reduced theory overpredicts skew amplitude away from the boundary; the zero location is the more robust reduced-order result. The boundary does not prescribe the finite-time trajectory: across a 36-condition rate–thickness study, 8 of 17 evaluable trajectories show collector-ward centroid motion followed by separator-ward recovery, and nearly matched cutoff capacities conceal different internal histories. Finally, differencing two depth-resolved stored-lithium profiles at matched delivered capacities recovers the capacity-window-averaged reaction distribution from two states, with predicted through-thickness contrasts reaching ∼33% in 150 µm electrodes.
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BibTeX
@misc{elgammal2026forced,
title = {{Forced Reaction Redistribution in High-Loading Lithium-Ion Cathodes}},
author = {Ramez A. Elgammal},
howpublished = {ChemRxiv},
year = {2026},
month = aug,
doi = {10.26434/chemrxiv.15008032/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008032/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Forced Reaction Redistribution in High-Loading Lithium-Ion Cathodes
AU - Ramez A. Elgammal
PY - 2026
DA - 2026/08/30
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008032/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008032/v1
AB - Classical secondary-current theory predicts a directionally neutral through-thickness reaction distribution when a porous electrode’s effective electronic and ionic conductivities are equal. In a working concentrated electrolyte, the salt-concentration gradient adds a thermodynamic contribution to electrolyte current that shifts this balance. A convention-consistent reduction of the porous-electrode equations shows that, in the quasi-steady weak-depletion onset limit, reaction skew vanishes when the electronic-to-ionic conductivity ratio equals 1/(1+ρe), or 0.390 for the reference electrolyte. Separator-favored reaction therefore persists well below the classical equal-conductivity condition. Full Doyle–Fuller–Newman (DFN) calculations reproduce ∼93% of the predicted boundary displacement across a 2.7-fold change in ρe, although the reduced theory overpredicts skew amplitude away from the boundary; the zero location is the more robust reduced-order result. The boundary does not prescribe the finite-time trajectory: across a 36-condition rate–thickness study, 8 of 17 evaluable trajectories show collector-ward centroid motion followed by separator-ward recovery, and nearly matched cutoff capacities conceal different internal histories. Finally, differencing two depth-resolved stored-lithium profiles at matched delivered capacities recovers the capacity-window-averaged reaction distribution from two states, with predicted through-thickness contrasts reaching ∼33% in 150 µm electrodes.
ER -