Electrolytic degradation of lithia-stabilized polycrystalline. beta. ''-alumina. Final report, September 1, 1977-November 30, 1983

Technical Report · Thu Mar 01 04:00:00 EST 1984

OSTI ID:5113159

Virkar, A V

The principal objective of the project was to theoretically and experimentally examine the degradation of Na-..beta..''-alumina which is used as a solid electrolyte separator in the Na-S battery as well as in the Na heat engine for direct conversion of heat into electricity. The theoretical development which occurred under this contract is however applicable to cationic solid electrolytes in general and not limited to Na-..beta..''-alumina. This is particularly important since now it is known that the ..beta..''-alumina lattice can be made to conduct a host of other ionic species. Thus, it is expected that solid electrolytes will find applications in various technological systems. As such, a thorough knowledge regarding their durability and failure mode is needed. Several pertinent features regarding failure were identified. Mathematical models were developed to quantitatively describe the mode of filament growth. It was subsequently shown that the three dimensional aspects of crack extension must be incorporated into the analysis. Mathematical models on crack extension included electrochemical aspects of metal/solid electrolyte interface. Experimental work involved a study of the behavior of ..beta..''-alumina solid electrolyte under the passage of current in Na/..beta..''/Na cells at temperatures up to 400/sup 0/C. Filament growth studies included room temperature electrolysis tests on Na-..beta..''-alumina, NASICON (Na/sub 3/Zr/sub 2/Si/sub 2/PO/sub 12/) and Ag-..beta..''-alumina. The effect of wetting between Na and Na-..beta..''-alumina on the degradation behavior was demonstrated experimentally as well as analytically. The wetting characteristics of sodium on Na-..beta..''-alumina and NASICON were studied using a sessile drop technique. A study was also initiated to conduct diffusion measurements in liquid and solid metallic alloys. Specifically, diffusivity of Na in molten Sn was determined.

• Research Organization: Utah Univ., Salt Lake City (USA). Dept. of Materials Science and Engineering
• DOE Contract Number: AC02-77ER04451
• OSTI ID: 5113159
• Report Number(s): DOE/ER/04451-28; UTEC-84-028; ON: DE84008668
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
250903* -- Energy Storage-- Batteries-- Materials
Components
& Auxiliaries
36 MATERIALS SCIENCE
360200 -- Ceramics
Cermets
& Refractories
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BATTERY SEPARATORS
CHALCOGENIDES
CHEMICAL REACTIONS
CRACK PROPAGATION
CRYSTAL GROWTH
DECOMPOSITION
DIFFUSION
ELECTRIC BATTERIES
ELECTROCHEMICAL CELLS
ELECTROLYTES
FILAMENTS
MATHEMATICAL MODELS
METAL-NONMETAL BATTERIES
OXIDES
OXYGEN COMPOUNDS
SODIUM-SULFUR BATTERIES
SOLID ELECTROLYTES