Mass transport induced asymmetry in charge/discharge behavior of liquid metal batteries

Autor: Paolo Personnettaz, Steffen Landgraf, Michael Nimtz, Norbert Weber, Tom Weier
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Electrochemistry Communications, Vol 105, Iss , Pp - (2019)
Druh dokumentu: article
ISSN: 1388-2481
DOI: 10.1016/j.elecom.2019.106496
Popis: Mass and charge transport in liquid metal batteries are closely intertwined because of the fully liquid interior of the cells. We found that charging and discharging cycles may show pronounced asymmetries. They are caused by the presence (charge) or absence (discharge) of solutal convection. While the direction of thermal gradients in the positive electrode of a liquid metal battery depends on boundary conditions and thermodynamics in a non-trivial manner, the solutal gradient predictably changes direction from charge to discharge. The unstable density distribution during charge drives a flow strong enough to prevent any concentration polarization. In contrast, during discharge, the stable density gradient suppresses convection and leads to a substantial mass transport overvoltage. We illustrate this scenario by experimental data, numerical simulations and a physical model. Keywords: Electrorefining, Liquid electrode, Liquid metal batteries, Mass transport, Overvoltage, Solutal convection
Databáze: Directory of Open Access Journals