58 nanotimes News in Brief

 Liquid-Metal Batteries // Multi-Faceted Magnetic Phenomenon Confirmed in the Lab © Based on Material by HZDR, Germany, Image © Tom Weier/HZDR

At the Helmholtz-Zentrum Dresden-Rossendorf  (HZDR, Germany), confirmation of a magnetic instability – the Tayler instability – was successfully achieved for the first time in collaboration with the Leibniz Institute for Astrophysics in Potsdam (AIP). The findings should be able to facilitate construction of large liquid-metal batteries.

The basic principle behind a liquid-metal battery is quite simple: since liquid metals are conductive, they can serve directly as anodes and cathodes. When one pours two suitable metals into a container so that the heavy metal is below and the lighter metal above, and then separates the two metals with a layer of molten salt, the arrangement becomes a galvanic cell. The metals have a tendency to form an alloy, but the molten salt in the middle prevents them from direct mixing. Therefore, the atoms of one metal are forced to release electrons. The ions thus formed wander through the molten salt. Arriving at the site of the other metal, these ions accept electrons and alloy with the second metal. During the charging process, this process is reversed and the alloy is broken up into its original components. In order to avoid the Tayler instability within big batteries – meaning a short circuit – the researchers suggest an internal tube through which the electrical current can be guided in reverse direction. This allows the capacity of the batteries to be considerably increased.

Martin Seilmayer et al.: Evidence for transient Tayler instability in a liquid metal experiment, In: Physical Review Letters, Vol. 108(2012), Issue 24, Article 244501 [4 pages], DOI:10.1103/PhysRevLett.108.244501:

http://dx.doi.org/10.1103/PhysRevLett.108.244501

Frank Stefani et al.: How to circumvent the size limitation of liquid metal batteries due to the Tayler instability, In: Energy Conversion and Management, Vol. 52(2011), Issues 8-9, August 2011, Pages 2982-2986, DOI:10.1016/j.enconman.2011.03.003:

http://dx.doi.org/10.1016/j.enconman.2011.03.003