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ENERGIX-Stort program energi

New thermoelectric ANtimonides and Silicides With EntRopy stabilization

Alternative title: Nye termoelektriske antimonider og silisider med entropi-stabilisering

Awarded: NOK 7.0 mill.

About 60% of the global primary energy consumption is lost during combustion and heat transfer processes. Energy recovery is therefore a key instrument to restrain the growing energy demand and lower greenhouse-gas emissions. Thermoelectric materials are critical for the successful conversion of waste heat; however, radically new materials must be developed for thermoelectricity to be brought into the world energy market. The scientific community has searched for decades for suitable thermoelectric materials and, although antimonides and silicides stand out as the most promising sustainable systems, they have not yet met the expectations and the field needs alternative research strategies. ANSWER developed unconventional antimonides and silicides through stabilization by substitutional disorder (configurational entropy). The strategy involved replacing a specific element in antimonides or silicides (such as zinc in zinc antimonide or manganese in manganese silicide) with many distinct elements (e.g., mixtures of chromium, iron, cobalt, nickel and copper instead of zinc or manganese). This substitution provided the disorder needed to lower thermal transport, which is key to improving thermoelectric behavior. In addition to the concept of entropy-stabilized covalent compounds for thermoelectricity conversion, ANSWER used a methodology integrating innovative fundamental and experimental approaches: (1) selection of substitutional elements by theoretical modeling and machine learning, (2) fabrication of complex (multiphase) materials, (3) probing at the nanoscale the phases that stand out in terms of thermoelectric conversion, (4) bulk production of the selected phases and (5) quantitative thermoelectric evaluation at the macroscale. Extensive composition domains have been probed for both antimonides and silicides and promising bulk single-phase materials have been synthesized by powder metallurgy techniques. Heusler and CoSb3-related antimonides showed interesting structural and thermoelectric behavior. In the case of silicides, high entropy compounds with the MoSi2 and FeSi structures stood out as the most interesting in terms of thermoelectric properties. The recommended follow-up actions include further fine-tuning of the promising high entropy compounds based on earth-abundant and non-toxic elements. This will be achieved through new joint applications to national and EU funding agencies. ANSWER enabled a deeper fundamental insight into the performance of compounds stabilized by configurational entropy as demonstrated by the scientific publications, as well as the popular dissemination activities, arising from the project.

ANSWER successfully engineered high entropy silicides and antimonides employing advanced theoretical and experimental methodologies. The research strategy involved: Machine Learning and Density Functional Theory tools to guide the systematic exploration of entropy-stabilized compounds; selecting candidate phases by correlating structure, composition and thermoelectric properties; evaluating the thermoelectric behavior of bulk entropy-stabilized materials produced by advanced powder metallurgy methods; and identifying suitable composition ranges for further applied research on thermoelectric materials. The project resulted in scientific renewal and progress beyond the state of the art in the field of functional high-entropy compounds. Significant scientific results from the present work include: the demonstration of entropy stabilization of an antimonide compound; new crystal structures adopted by high-entropy compounds; interesting fundamental behavior such as inversion from p-type to n-type conduction with temperature. The ANSWER project allowed the groups involved at SINTEF and UiO to strengthen their knowledge in the fields of powder metallurgy, high entropy compounds and thermoelectric behavior. In addition, a series of theoretical tools and experimental protocols have been developed, serving as basis for further research. Dissemination was an integral part of all work packages; thus, the research concept and its results were extensively disseminated during the course of the project as attested by the scientific and popular science entries added to the National repository. Notably, two master theses were also carried out in the framework of the project. ANSWER´s results, including the still ongoing activities, will be presented to industry stakeholders interested in high entropy materials, as well as in thermoelectric applications, in a workshop to be held in June 2023. Communication with society will increase attention to sustainability, pointing the way forward.

About 60% of the global primary energy consumption is lost during combustion and heat transfer processes. Thus, energy recovery is a key instrument to restrain the growing global energy demand and lower greenhouse-gas emissions. Thermoelectric materials are critical for successful conversion of waste heat; however, radically new materials must be developed for thermoelectricity to be brought into the world energy market. The scientific community has searched for decades for suitable thermoelectric materials and, although antimonides and silicides stand out as the most promising sustainable systems, they have not yet met the expectations and the field needs alternative research strategies. ANSWER proposes engineering unconventional antimonides and silicides through stabilization by configurational entropy. The strategy involves populating sublattice(s) of antimonides and silicides with nearly-equimolar mixtures of many distinct elements. The occupancy disorder will provide the anharmonicity needed to lower thermal transport, which is key to improve the thermoelectric behavior. In addition, to the concept of entropy-stabilized covalent compounds for thermoelectricity conversion, ANSWER proposes an integrated fundamental and experimental methodology to develop thermoelectric materials: (1) design of the substitutional element set by ab-initio calculations, (2) fabrication of metastable materials followed by relaxation into near-equilibrium structures in multiphase configurations, (3) obtain correlative maps of structure-composition-thermoelectric properties by local probing to scout for disordered crystalline phases that stand out in terms of thermoelectric conversion, (4) bulk production of selected phases and (5) quantitative thermoelectric evaluation to obtain benchmark values. If successful, this project will have impact on global energy management and will give tremendous contributions to materials technology and fundamental materials science.

Publications from Cristin

Funding scheme:

ENERGIX-Stort program energi

Thematic Areas and Topics

IKTBransjer og næringerProsess- og foredlingsindustriInternasjonaliseringDigitalisering og bruk av IKTBransjer og næringerIKTIKT - Bruk og anvendelser i andre fagGrunnforskningDigitalisering og bruk av IKTPrivat sektorLTP3 Et kunnskapsintensivt næringsliv i hele landetDelportefølje InternasjonaliseringLavutslippPortefølje InnovasjonLTP3 Klima, miljø og energiNanoteknologi/avanserte materialerAvanserte materialerLTP3 Fagmiljøer og talenterLTP3 IKT og digital transformasjonLTP3 Nano-, bioteknologi og teknologikonvergensDelportefølje Et velfungerende forskningssystemLTP3 Styrket konkurransekraft og innovasjonsevneInternasjonaliseringInternasjonalt prosjektsamarbeidNaturmangfold og miljøDelportefølje KvalitetMiljøteknologiNanoteknologi/avanserte materialerNanovitenskapPortefølje ForskningssystemetEnergiMiljøvennlig energiMiljøvennlig energi, annetBransjer og næringerEnergi - NæringsområdeBruk/drift av forskningsinfrastrukturPolitikk- og forvaltningsområderPortefølje Muliggjørende teknologierKlimarelevant forskningPolitikk- og forvaltningsområderEnergi - Politikk og forvaltningLTP3 Høy kvalitet og tilgjengelighetPortefølje Energi og transportLTP3 Miljøvennlig energi og lavutslippsløsningerLTP3 Muliggjørende og industrielle teknologierNanoteknologi/avanserte materialerPortefølje Banebrytende forskningEnergiMiljøvennlig energi, annetNaturmangfold og miljøBærekraftig energiGlobale utfordringerMiljøteknologiAnnen miljøteknologiNaturmangfold og miljøMiljøteknologi