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arXiv · 2609.02968

Battery open-circuit voltage is not purely chemical

Andrea Giudici·Christoph Pohl·Alberto Salvadori·Colin Please·Manuel Landstorfer·Jon Chapman
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Abstract

Open-circuit-voltage (OCV) curves are commonly treated as intrinsic chemical properties of electrode materials. However, this view is incomplete. In ion-insertion batteries, OCV also depends on mechanical state and microstructure. Using finite-element simulations and asymptotic analysis, we show that particle swelling and external loads promote particle--particle contact that generates compressive stresses, shifting the inserted-ion chemical potential. The OCV correction is nonlinear, follows Hertzian contact scaling, and depends on particle arrangement. Identical materials can therefore exhibit different OCV curves in different electrode microstructures. Furthermore, in full cells, electrodes are mechanically coupled through the common stack stress. Thus, cell OCV is a chemo-mechanical property of the entire battery architecture, not chemistry alone.

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Andrea Giudici, Christoph Pohl, Alberto Salvadori, Colin Please, Manuel Landstorfer, Jon Chapman. 2026-09-02. Battery open-circuit voltage is not purely chemical. https://arxiv.org/abs/2609.02968

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