DISSOLUTION OF BORON IN LITHIUM MELT

The lithium-boron system has been extensively studied due to the pract ical importance of Li-B alloys as anode materials for the production o f lithium batteries. However, many questions remained unexplained, and the phase diagram has not been determined. Some ambiguities also rema ined regarding the existence of a LiB3 compound and the dissolution of boron in lithium melt. To resolve these questions an approach using a b initio molecular orbital (MO) calculations on the Hartree-Fock (HF) level of theory is presented. Stability and rules of bonding for lithi um-boron clusters were calculated using STO-3G, 3-21G, and 6-31G basi s sets. The calculations enabled a formulation of the rules of bonding in lithium-boron clusters which gave a suggestions to the possible me chanism of the interaction of molten lithium with crystalline boron. E xperimental evidence based on chemical and X-ray diffraction analyses, supporting the results of MO calculations, is also given and a new ex planation, which covers all experimental and theoretical data about th e processes which occur during the heating of the lithium-boron mixtur e in the temperature range 300-400 degrees C is presented.