Electrochemical Nucleation and Growth in Battery Electrodes under Reactant-Limited Conditions

Nucleation and growth of solid phases from species dissolved in an electrolyte govern battery performance, defining capacity, efficiency, rate capability, stability, and safety. However, classical nucleation-growth models often do not realistically describe working cells, failing to capture highly asymmetric out-of-plane growth and finite reactant supply. Here, we introduce a nucleation-growth model to fit potentiostatic nucleation transients that explicitly accounts for a finite amount of reactant and its depletion, reproducing the characteristic current rise upon nucleation, peak, and subsequent decay without ad hoc corrections. Both instantaneous nucleation and progressive nucleation are considered. The model is applied to the nucleation and growth of Li2S at a catalyzed electrode from a lithium polysulfide solution, yielding nucleus densities of up to 6.7 × 109 cm-2 and an effective reaction rate constant of 1.8 × 10-3 s-1. Beyond Li-S batteries, the framework can be extended to other conversion and metal-deposition chemistries in which finite-supply effects dominate.