Differentiable Solvation Shell Model for Rational Electrolyte Design

Hancheng Zhao; Hongyi Lin; Celia Kelly; Venkatasubramanian Viswanathan

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arXiv · 2609.05671

Differentiable Solvation Shell Model for Rational Electrolyte Design

Hancheng Zhao·Hongyi Lin·Celia Kelly·Venkatasubramanian Viswanathan

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Abstract

Tailoring Li+ solvation structures has emerged as a promising design principle across multiple Li metal battery (LMB) electrolytes, with localized high concentration electrolytes (LHCE) emerging as a leading candidate. However, rational design of these electrolytes remains limited by a poor quantitative understanding of how molecular properties govern Li+ solvation shell composition. Here we introduce a mean field modeling framework, built on an Ising model, that predicts solvation shell composition from donor number (DN), acceptor number (AN), molar ratio, and molecular size. This framework is end-to-end differentiable, which enables parameterization directly from molecular dynamics (MD) solvation structures via gradient-based optimization. Focusing on LHCE, the model achieves 10.7% RMSE and R2=0.87 for shell composition, 2.3% RMSE on free solvent ratio, and further reproduces solvation trends in real LHCE electrolytes, at a fraction of MD's cost. Our model also shows good generalizability on other electrolyte systems in addition to LHCE. Analysis of its interaction terms shows that DN dominates Li+ solvation energetics, providing a thermodynamic basis for empirical DN-based design rules. We further demonstrate the model's design utility on the LiTFSI/tetraglyme (G4) system absent from training. The model identifies fluorobenzene (FB) as a promising diluent and predicts a salt-concentration window with anion-rich solvation shells and low free solvent, favorable for stable anion-derived SEIs and high oxidative stability, respectively. This prediction is validated by higher-fidelity MD. This work establishes an interpretable differentiable framework for predicting Li+ solvation shell composition, with potential to extend to other electrolyte classes.

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Hancheng Zhao, Hongyi Lin, Celia Kelly, Venkatasubramanian Viswanathan. 2026-09-04. Differentiable Solvation Shell Model for Rational Electrolyte Design. https://arxiv.org/abs/2609.05671

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