Redox reactions with empirical potentials: Atomistic battery discharge simulations

TL;DR

This paper introduces a novel atomistic simulation approach using redoxSQE to model complete batteries, focusing on electrode-electrolyte interfaces and capturing key discharge behaviors.

Contribution

It presents the first self-consistent atomistic model of a full battery, enabling detailed study of interfacial phenomena and discharge processes.

Findings

Reproduces qualitative battery discharge properties

Shows capacity dependence on temperature and rate

Demonstrates performance degradation upon recharge

Abstract

Batteries are pivotal components in overcoming some of today's greatest technological challenges. Yet to date there is no self-consistent atomistic description of a complete battery. We take first steps toward modeling of a battery as a whole microscopically. Our focus lies on phenomena occurring at the electrode-electrolyte interface which are not easily studied with other methods. We use the redox split-charge equilibration (redoxSQE) method that assigns a discrete ionization state to each atom. Along with exchanging partial charges across bonds, atoms can swap integer charges. With redoxSQE we study the discharge behavior of a nano-battery, and demonstrate that this reproduces the generic properties of a macroscopic battery qualitatively. Examples are the dependence of the battery's capacity on temperature and discharge rate, as well as performance degradation upon recharge.