Batteries for renewable energy storage could be made cheaper

It has previously been possible to create liquid metal batteries on a small scale but these have encountered mixing problems when they are scaled up to the sizes that are required to store energy from renewable energy sources, such as solar panels and wind turbines.

The so-called ‘stirring’ that occurs in larger liquid metal batteries is a result of the liquids being mixed up due to forces that arise when the current flows between the anode and the cathode.

‘This mixing destroys the functioning of the stratification and the functioning of the battery,’ said Dr Frank Stefani from the Institute of Fluid Dynamics at Helmholtz-Zentrum Dresden-Rossendorf.

The Japanese came up with a solution to overcoming the mixing problem — using sodium and sulphur as the two liquid layers — but this is still relatively expensive. Stefani explained that his team’s approach, which uses relatively cheap metals such as indium, gallium and tin, could be three to five times cheaper than the Japanese batteries.