A continuous multiphase model for liquid metal batteries

TL;DR

This paper develops a detailed 1D multiphase numerical model to simulate the discharge process in Na-Zn liquid metal batteries, capturing complex mass transport, interfacial dynamics, and electrolyte composition variations.

Contribution

It introduces a novel multiphase model that predicts electrolyte composition, species distribution, and capacity effects in Na-Zn LMBs, enhancing understanding of their operation.

Findings

Electrolyte composition varies significantly during discharge.

Volume change and species redistribution impact maximum capacity.

Neglecting convection affects capacity predictions.

Abstract

Liquid metal batteries (LMBs) are a promising alternative for large-scale stationary energy storage for renewable applications. Using high-abundance electrode materials such as Sodium and Zinc is highly desirable due to their low cost and excellent cell potential. LMBs undergo multiple complex mass transport dynamics and as a result, their operation limits and other critical parameters are not fully understood yet. In this work, a multiphase numerical model was developed to resolve electrode and electrolyte components in 1D and simulate the discharge process of a Na-Zn battery including the interfacial displacement of the molten metal electrodes. The variation in electrolyte composition was predicted throughout the process, including the species distribution and its effect on the cell conductivity and capacity. Volume change and species redistribution were found to be important in predicting the maximum theoretical capacity of the cell when neglecting convective phenomena.