ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The layered cobalt oxides as thermoelectric (TE) materials are introduced in detail on theirdevelopments, representative systems, some theories, unsolved problems and approaches for improvingperformances. TE performances of the layered cobalt oxides are discussed from structures, dopedsituations, processes and the dimensionless figure of merit. In contrast with other TE materials, thelayered cobalt oxides show many promising applications. The theory of Seebeck coefficient and hoppingconduction mechanism in the layered cobalt oxides are discussed. Heike formula explains that Seebeckcoefficient origins from electronic spin states and proportions of different value states of Co ion. Anunbalance of the spin and orbital degrees of freedom between Co3+ and Co4+ sites results in the largeSeebeck coefficient. On the basis of the Boltzmann transport equation, Seebeck coefficient is decided byenergy band structures. High state density near Fermi Energy band is responsible for the coexistence oflarge Seebeck coefficient and high electrical conductivity. Hopping conduction mechanism found inexperiments is a main transport way of charge carriers at high temperature for the layered cobalt oxides.Through different materials systems and theories analysis, unsolved problems and new approaches forimproving TE performances are put forward
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/53/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.336-338.814.pdf
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