Synthesis and Structural Characterization of Novel Intermetallic Clathrates – Prospective Materials for Thermoelectric Applications

Technical Report · Thu Aug 01 04:00:00 EDT 2013

OSTI ID:1089002

Bobev, Svilen ^[1]

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1. Univ. of Delaware, Newark, DE (United States); University of Delaware

The overall objective of the project is to contribute to the development of the fundamental chemistry and physics of new intermetallic clathrates (open framework materials) that can find applications in solid-state energy conversion. Such materials are termed thermoelectric materials and they possess the unique property that a temperature gradient induces a separation of charge in them. Thermoelectric materials are of great practical importance because of their potential for widespread applications in power generation or in cooling devices. Recently, new complex inorganic materials with open framework structures, such as skutterudites and clathrates have been suggested to be a breakthrough in the thermoelectric energy conversion. The basic hypothesis for the thermoelectric properties of such “host-guest” structures is that the conducting host-framework provides a high Seebeck coefficient (S) and electrical conductivity (σ), while low-lying optical modes, associated with the vibration of the guest-atoms, hybridize with the acoustic modes. The proposed interdisciplinary efforts are the initial part of a broader, collaborative program to investigate the structure-bonding-properties relationships in related intermetallic compounds. More specifically, our work is aimed at: 1. Comprehensive and systematic investigations of the crystal chemistry and stoichiometry breadth of new semiconducting clathrates with the type-II or type-III structures. 2. Precise determination of the composition with minimum occupancy of the cages, needed for the thermodynamic stability of the clathrate framework, coupled with investigations to verify the possibility of “rattling” atoms inside the open-framework structure. 3. Extensive physical property measurements (S, σ, k, R_H, C_p, $$\chi_{m}$$). Ultimately, this new phenomenology will be used as a foundation for the rational tuning of potentially interesting properties of the newly synthesized materials.

• Research Organization: Univ. of Delaware, Newark, DE (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: SC0001360
• OSTI ID: 1089002
• Report Number(s): DOE-SC--0001360-1
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Cage Compounds
Clathrates
Crystal Structure
Layered Compounds
Zintl Phases