Experimental studies of the electronic structure of I-II and I-III intermetallic compounds: Progress report, June 15, 1985-January 14, 1986

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7063702

Curelaru, I M

The interest in a detailed study of I-II, I-III intermetallic compounds stems from their potential use as electrode materials in high energy density batteries or as solid blankets for nuclear reactors. There also exists a basic interest in the problem, because only a reduced number of I-II, I-III intermetallics (LiAl, LiGa, LiIn, LiZn, LiCd, and NaTl) crystallize in the unusual B32 (Zintl) structure, while others belong to the B2 (CsCl-type) structure. The compound stability and a number of physical properties are essentially different in the two types of I-II, I-III intermetallics. The beta phase of the B32 (Zintl) structure is composed of two interpenetrating diamond-like lattices, one for each constituent element. Most extensive experimental studies have been devoted to LiAl, a mixed electronic and ionic conductor, because of its use as an electrode in lithium-based batteries. These studies include x-ray and neutron diffraction, Hall coefficient, Knight shift, and conductivity measurements. Various approaches to theoretical band structure and cluster model calculations are also available, but their material description and prediction of basic properties are strongly model-dependent and are at variance with each other and with the existing experimental data. The situation is complicated even more by the fact that the beta-Zintl compounds incorporate a significant number of complex constitutional defects at all compositions and temperatures. In Li/sub x/Al/sub 1-x/, lithium vacancies (V/sub Li/) and lithium antisite defects (Li/sub Al/) coexist over the whole composition range (x = 0.48 to x = 0.55), and each of them dominates at one end of the phase. Moreover, evidence exists that lithium vacancies are trapped by lithium antisites, thus limiting the existence of free lithium vacancies to the Li-poor end of the beta-phase.

• Research Organization: Utah Univ., Salt Lake City (USA). Dept. of Materials Science and Engineering
• DOE Contract Number: FG02-84ER45143
• OSTI ID: 7063702
• Report Number(s): DOE/ER/45143-T2; ON: DE88016910
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
656002* -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALI METALS
ALLOYS
ALUMINIUM
DATA PROCESSING
DOCUMENT TYPES
ELECTRONIC STRUCTURE
ELEMENTS
ETCHING
GALLIUM
INTERMETALLIC COMPOUNDS
LITHIUM
METALS
PROCESSING
PROGRESS REPORT
RESEARCH PROGRAMS
SURFACE FINISHING