Enthalpy of formation of Li2Sb and Li3Sb and mixing enthalpy of liquid Li–Sb alloys

Abstract

The enthalpies of formation of Li3Sb and Li2Sb intermetallics and mixing enthalpy of liquid Li–Sb alloys were measured with the use of two calorimetric techniques. The direct reaction calorimetric method was used to measure the formation enthalpy of Li3Sb at 942 K (four separate measurements) and Li2Sb at 820 K (three separate measurements). The enthalpies of formation of Li3Sb and Li2Sb were equal to −70.3 ± 0.3 kJ/mol at. and −66.7 ± 0.5 kJ/mol at., respectively. The partial and integral mixing enthalpies were measured in the Li–Sb system by using the drop calorimetry in three separate series starting from the lithium side at 820 K, 942 K, 1024 K and one series starting from the antimony side at 922 K. The integral molar mixing enthalpy has negative values in the whole concentration range. Partial enthalpies of Li agree with available data from electrochemical measurements. Partial enthalpies of Sb are generally constant, which indicates they were measured in the liquid–solid range.