Beta-alumina solid electrolyte

Beta-alumina solid electrolyte

Beta-alumina solid electrolyte (BASE) is a fast ion conductor material used as a membrane in several types of molten salt electrochemical cell. There is no known substitute.

β"-Alumina ("beta prime-prime alumina") is an isomorphic form of aluminium oxide (Al2O3) a hard polycrystalline ceramic in which when prepared as an electrolyte is complexed with a mobile ion, which may be Na+, K+ , Li+ , Ag+ , H+ , Pb2+ , Sr2+ or Ba2+ depending on the application. Beta-alumina is a good conductor of its mobile ion yet allows no non-ionized conductivity.

Sodium beta alumina is a non-stoichiometric sodium aluminate known for its rapid transport of Na+ ions. This material selectively passes sodium ions while containing all other liquids, including liquid sodium and liquid sulfur. It is a ceramic which can be formed and sintered by commercially available techniques and its conductivity at operating temperatures — 250 to 300 degrees Celsius — compares favorably with electrolytes used in conventional battery systems such as sulfuric acid and potassium hydroxide. The crystal structure of the Na-Al2O3 provides an essential rigid framework with channels along which the ionic species of the solid can migrate. Ion transport involves hopping from site to site along these channels.

BASE was first developed by researchers at the Ford Motor Company, in the search for a storage device for electric vehicles while developing the sodium-sulfur battery. The NaS battery consists of sulfur at positive electrode, sodium at negative electrode as active materials, and Beta alumina of sodium ion conductive ceramic which separates both electrodes.This hermetically sealed battery is kept at approximately 300 degrees Celsius and is operated under the condition that the active materials at both electrodes are liquid and its electrolyte is solid. At this temperature, since both active materials react smoothly, and internal resistance becomes low enough, the NaS battery has excellent performance. Because of reversible charging and discharging, the NaS battery can be continuously used. Several commercial installations use this type of battery for load leveling.

The sodium sulfur battery was a topic of intense worldwide interest during the 1970s and 1980s, but interest in the technology for vehicle use diminished for a variety of technical and economic reasons. In contrast, its "successor", the sodium nickel chloride battery, is now entering the commercialization phase. The sodium nickel chloride battery (or ZEBRA battery, so-called for the Zeolite Battery Research Africa Project) has been under development for almost 20 years. Y.F.Y. Yao and J.T. Kummer, J. Inorg. Nucl. Chem. 29 (1967) p. 2453

When BASE is used in a sodium nickel chloride (ZEBRA) cell, several requirements must be met. It must have a low resistivity, typically 4 cm at 350 °C, and a strength in excess of 200 MPa. It must be produced in the form of a thin-walled (1.25 mm), convoluted tube by low-cost production methods, and it must maintain a stable resistance in the cell for up to 10 years. These requirements have mostly been met by a variation of the sol-gel process.

BASE is also used in alkali-metal thermal to electric converters. (AMTEC) AMTEC is a high efficiency device for directly converting heat to electricity. AMTEC operates as a thermally regenerative electrochemical cell by expanding sodium through the pressure differential across the (BASE) membrane. BASE electrolytes have been used in some molten-carbonate fuel cells, as well as other liquid electrode/solid electrolyte fuel cell designs.

References


* [http://www.rcub.bg.ac.yu/~todorom/tutorials/rad23.html Hybridization and Cogeneration with Concentrated Solar Radiation (CSR) Technology]
* [http://rruff.geo.arizona.edu/doclib/zk/vol127/ZK127_94.pdf The alkali problem in the crystal structure of beta alumina]
* [http://hrst.mit.edu/hrs/materials/public/Whittingham/Whit_publs/Whit_on_beta_alumina.htm BETA ALUMINA - PRELUDE TO A REVOLUTION IN SOLID STATE ELECTROCHEMISTRY]
* [http://www.sfc.fr/Material/hrst.mit.edu/hrs/materials/public/Beta-alumina.htm Trajectory of beta-alumina]


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Glossary of fuel cell terms — The Glossary of fuel cell terms lists the definitions of many terms used within the fuel cell industry. The terms in this glossary may be used by fuel cell industry associations, in education material and fuel cell codes and standards to name but …   Wikipedia

  • Molten salt battery — Molten salt batteries or liquid sodium battery are a class of primary cell and secondary cell high temperature electric battery that use molten salts as an electrolyte. They offer both a higher energy density through the proper selection of… …   Wikipedia

  • Fast ion conductor — Fast ion conductors, also known as solid electrolytes and superionic conductors, are solid state electrical conductors which conduct due to the movement of ions through voids (or empty crystallographic positions)in their crystal lattice. One… …   Wikipedia

  • Sodium–sulfur battery — Cut away schematic diagram of a sodium–sulfur battery. (image courtesy NASA John Glenn Research Center). A sodium–sulfur battery or liquid metal battery is a type of molten metal battery[1] constructed from sodium (Na) and sulfur ( …   Wikipedia

  • Alkali-metal thermal to electric converter — The Alkali Metal Thermoelectric Converter (AMTEC) is a thermally regenerative electrochemical device for the direct conversion of heat to electrical energy. It is characterized by high potential efficiencies and no moving parts, which make it a… …   Wikipedia

  • Molten carbonate fuel cell — Scheme of a molten carbonate fuel cell Molten carbonate fuel cells (MCFCs) are high temperature fuel cells, that operate at temperatures of 600°C and above. Molten carbonate fuel cells (MCFCs) are currently being developed for natural gas, biogas …   Wikipedia

  • Pile a combustible a carbonate fondu — Pile à combustible à carbonate fondu Schéma d une MCFC Les piles à combustible à carbonate fondu, ou MCFC (d après l acronyme de l appellation anglaise Molten carbonate fuel cell) sont des piles à combustible fonctionnant à des températures à… …   Wikipédia en Français

  • Pile à combustible à carbonate fondu — Schéma d une MCFC Les piles à combustible à carbonate fondu, ou MCFC (d après l acronyme de l appellation anglaise Molten carbonate fuel cell) sont des piles à combustible fonctionnant à des températures à partir de 600 °C et au delà. Elles… …   Wikipédia en Français

  • Sodium-sulfur battery — A sodium sulfur battery is a type of battery constructed from sodium (Na) and sulfur (S). This type of battery has a high energy density, high efficiency of charge/discharge (89 mdash;92%) and long cycle life, and is fabricated from inexpensive… …   Wikipedia

  • Electromotive force — (emf, mathcal{E}) is a term used to characterize electrical devices, such as voltaic cells, thermoelectric devices, electrical generators and transformers, and even resistors. For a given device, if an electric charge Q passes through that device …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”