Mass transfer in liquid metal batteries

A perfect mass transfer is mandatory for an efficient operation of liquid metal batteries. Especially the positive electrode of the cell should always be well mixed. Mass transfer in liquid metal batteries determines

• the cell voltage
• possible discharge currents
• the cell capacity

In order to achieve an optimal efficiency, the mass transfer in liquid metal batteries needs to be optimised. For this purpose a large number of flow phenomena may be used, as e.g.

• Tayler instability
• electro-vortex flow
• interface instabilities
• thermal convection
• solutal convection
• Marangoni convection

These phenomena are studied at HZDR experimentally, but also numerically using the open source CFD software OpenFOAM.

Flow phenomena

Thermal Effects in Liquid Metal Batteries

Thermal convection appears in liquid metal batteries mainly in the anode, but also in the electrolyte of the cell.

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Electro-Vortex Flow

Electro-vortex flow may appear when an electric current di­verges or con­verges inside a liquid conductor.

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Interfacial instabilities

The metal pad roll instability limits the possible electrolyte layer thickness as well as the electric current for aluminium reduction cells as well as liquid metal batteries.

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The Tayler Instability

The Tayler instability limits the up-scalability of liquid metal batteries and plays a major role in astrophysics.

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Solutal convection

Solutal convection appears when charging a liquid metal battery, and improves mass transfer substantially.

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Radiography of liquid metal batteries

Neutrons and X-rays are used to visualize processes in liquid metal batteries. Cells imaging is performed in operando at temperatures exceeding 600°C.

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Modelling of molten salt electrolytes

Mass transfer in molten salt electrolytes determines the efficiency of liquid metal batteries.

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Publications

• Sarma, M.; Shevchenko, N.; Weber, N.; Weier, T.
  Operando characterisation of Na-Zn molten salt batteries using X-ray radiography: insights into performance degradation and cell failure
  Energy Storage Materials 83(2025) 104654
• Personnettaz, P.; Landgraf, S.; Weier, T.; Weber, N.; Eckert, S.
  Schaltungsanordnungen mit elektrochemischer Zelle und Verfahren zum Betrieb einer elektrochemischen Zelle
  German patent DE 10 2020 134 881
• Duczek, C.; Weber, N.; Nash, W.; Sarma, M.; Weier, T.
  Solutal convection in Na–Zn liquid metal batteries and its impact on self-discharge
  Physics of Fluids 37(2025) 023370
• Duczek, C.; Horstmann, G. M.; Ding, W.; Einarsrud, K. E.; Gelfgat, A. Y.; Godinez-Brizuela, O. E.; Kjos, O. S.; Landgraf, S.; Lappan, T.; Monrrabal, G.; Nash, W.; Personnettaz, P.; Sarma, M.; Sommerseth, C.; Trtik, P.; Weber, N.; Weier, T.
  Fluid mechanics of Na-Zn liquid metal batteries
  Applied Physics Reviews 11(2024), 041326
• Sarma, M.; Lee, J.; Nash, W.; Lappan, T.; Shevchenko, N.; Landgraf, S.; Monrrabal, G.; Trtik, P.; Weber, N.; Weier, T.
  Reusable cell design for high-temperature (600°C) liquid metal battery cycling
  Journal of the Electrochemical Society 171(2024) 040531
• Personnettaz, P.; Klopper, T. S.; Weber, N.; Weier, T.
  Layer coupling between solutal and thermal convection in liquid metal batteries
  International Journal of Heat and Mass Transfer 188(2022) 122555
• Personnettaz, P.; Landgraf, S.; Nimtz, M.; Weber, N.; Weier, T.
  Effects of current distribution on mass transport in the positive electrode of a liquid metal battery
  Magnetohydrodynamics 56(2020) 247-254
• Herreman, W.; Bénard, S.; Nore, C.; Personnettaz, P.; Cappanera, L.; Guermond, J.-L.
  Solutal buoyancy and electrovortex flow in liquid metal batteries
  Physical Review Fluids 5(2020) 074501
• Weber, N.; Nimtz, M.; Personnettaz, P.; Weier, T.; Sadoway, D.
  Numerical simulation of mass transfer enhancement in liquid metal batteries by means of electro-vortex flow
  Journal of Power Sources Advances 1(2020) 100004
• Personnettaz, P.; Landgraf, S.; Nimtz, M.; Weber, N.; Weier, T.
  Mass transport induced asymmetry in charge/discharge behavior of liquid metal batteries
  Electrochemistry Communications 105(2019) 106496
• Weber, N.; Landgraf, S.; Mushtaq, K.; Nimtz, M.; Personnettaz, P.; Weier, T.; Zhao, J.; Sadoway, D.
  Modeling discontinuous potential distributions using the finite volume method, and application to liquid metal batteries
  Electrochimica Acta 318(2019) 857-864
• Weber, N.; Nimtz, M.; Personnettaz, P.; Salas, A.; Weier, T.
  Electromagnetically driven convection suitable for mass transfer enhancement in liquid metal batteries
  Applied Thermal Engineering 143(2018) 293-301
• Ashour, R.; Kelley, D.; Salas, A.; Starace, M.; Weber, N.; Weier, T.
  Competing forces in liquid metal electrodes and batteries
  Journal of Power Sources 378(2018) 301-310
• Kelley, D.; Weier, T.
  Fluid mechanics of liquid metal batteries
  Applied Mechanics Reviews 70(2018) 020801