Corrosion Investigations of Materials in Antimony-Tin and Antimony-Bismuth Alloys for Liquid Metal Batteries

摘要

Liquid metal batteries are discussed as stationary electrical energy storage for renewable energies, in order to compensate their fluctuating supply of energy. A liquid metal battery consists of three different liquids, which stay segregated due to density differences and mutual immiscibility. The negative electrode is the low-density liquid metal, and in our case sodium, a medium density molten salt, is the electrolyte and positive electrode is a high-density liquid metal. For the latter, Sb-Sn and Sb-Bi alloys are selected. However, one issue is the compatibility of structural materials with the used liquids. In a first step, the behavior of potential structural materials in Sb_3Sn_7 and SbBi_9 at the temperature of 450 °C up to 750 h was tested. The results showed that the corrosion in SbBi_9 was significantly less than in Sb_3Sn_7 and the most promising materials were molybdenum meta and Max-phase coatings.