Preparation and electrochemical characterisation of aluminium liquid battery cells with two different electrolytes (NaCl-BaCl2-AlF3-NaF and LiF-AlF3-BaF2)

Abstract

The possibility of preparation of operating rechargeable liquid battery cells based on aluminium and its alloys is systematically checked. In all cases we started from aluminium as the negative electrode whereas as the positive electrode three different metals were tested: Pb, Bi and Sn. Two types of electrolytes were selected: Na₃AlF₆ -AlF₃ - BaCl₂ - NaCl and Li₃AlF₃ – BaF₂. We show that some of these combinations allowed efficient separation of individual liquid layers. The cells exhibited expected voltages, relatively high current densities and could be charged and discharged several times. The capacities were relatively low (120 mAh in the case of Al-Pb system), mostly due to unoptimised cell construction. Improvements in various directions are possible, especially by hermetically sealing the cells thus preventing salt evaporation. Similarly, solubility of aluminium in alloys can be increased by optimising the composition of positive electrode.