{"id":{"repo_id":"uic","oai_identifier":"oai:figshare.com:article/31451635"},"canonical_url":"https://search.dev.ndltd.org/etd/uic/oai:figshare.com:article/31451635","repository":{"repo_id":"uic","name":"University of Illinois - Chicago","base_url":"https://api.figshare.com/v2/oai"},"display":{"title":"Study of Functional Complex Oxides at High Pressure-Temperature Conditions","abstract":"Complex oxides are a diverse family of functional materials whose stability and transformations under extreme conditions are central to chemistry, energy research, and the design of novel compounds. This dissertation focuses on lithium cobalt oxyfluoride (Li2CoO2F), a Li-rich disordered rock-salt cathode, together with other representative complex oxides studied under high pressures and temperatures. Synchrotron X-ray diffraction, Raman spectroscopy, neutron scattering, and first-principles calculations were used to probe the structural response of Li2CoO2F across multiple length scales. These studies reveal how fluorination and Li enrichment promote local spinel-like motifs, stabilize metastable frameworks, and modify the elastic behavior under compression and heating. Complementary work on PbTiO3 demonstrates how kinetic barriers and thermodynamic driving forces combine to stabilize unexpected dissociation products, including a previously unreported PbO polymorph at megabar pressures. High-entropy oxide nanoribbons were also examined, with high-pressure experiments showing transformations from orthorhombic to cubic and ultimately amorphous states, underscoring their structural resilience and entropic complexity. Overall, this work provides new insight into the structural response of Li2CoO2F and related oxides under extreme conditions, highlighting how fluorination and Li enrichment influence their stability.","abstract_html":"Complex oxides are a diverse family of functional materials whose stability and transformations under extreme conditions are central to chemistry, energy research, and the design of novel compounds. This dissertation focuses on lithium cobalt oxyfluoride (Li2CoO2F), a Li-rich disordered rock-salt cathode, together with other representative complex oxides studied under high pressures and temperatures. Synchrotron X-ray diffraction, Raman spectroscopy, neutron scattering, and first-principles calculations were used to probe the structural response of Li2CoO2F across multiple length scales. These studies reveal how fluorination and Li enrichment promote local spinel-like motifs, stabilize metastable frameworks, and modify the elastic behavior under compression and heating. Complementary work on PbTiO3 demonstrates how kinetic barriers and thermodynamic driving forces combine to stabilize unexpected dissociation products, including a previously unreported PbO polymorph at megabar pressures. High-entropy oxide nanoribbons were also examined, with high-pressure experiments showing transformations from orthorhombic to cubic and ultimately amorphous states, underscoring their structural resilience and entropic complexity. Overall, this work provides new insight into the structural response of Li2CoO2F and related oxides under extreme conditions, highlighting how fluorination and Li enrichment influence their stability.","abstract_has_math":false,"creators":["Husam Farraj (23292013)"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-12-01T00:00:00Z","date_published":"2025-12-01T00:00:00Z","updated_at":"2026-07-27T21:34:29Z","subjects":["Chemistry","Inorganic"],"languages":[],"rights":["In Copyright","Open Access after 2028-01-01"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://doi.org/10.25417/uic.31451635.v1","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Husam Farraj (23292013)"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-12-01T00:00:00Z"]},{"key":"dc:relation","label":"Dc Relation","values":["https://figshare.com/articles/thesis/Study_of_Functional_Complex_Oxides_at_High_Pressure-Temperature_Conditions/31451635"]},{"key":"dc:type","label":"Dc Type","values":["Text","Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry","Inorganic"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright","Open Access after 2028-01-01"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["10.25417/uic.31451635.v1"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Complex oxides are a diverse family of functional materials whose stability and transformations under extreme conditions are central to chemistry, energy research, and the design of novel compounds. This dissertation focuses on lithium cobalt oxyfluoride (Li2CoO2F), a Li-rich disordered rock-salt cathode, together with other representative complex oxides studied under high pressures and temperatures. Synchrotron X-ray diffraction, Raman spectroscopy, neutron scattering, and first-principles calculations were used to probe the structural response of Li2CoO2F across multiple length scales. These studies reveal how fluorination and Li enrichment promote local spinel-like motifs, stabilize metastable frameworks, and modify the elastic behavior under compression and heating. Complementary work on PbTiO3 demonstrates how kinetic barriers and thermodynamic driving forces combine to stabilize unexpected dissociation products, including a previously unreported PbO polymorph at megabar pressures. High-entropy oxide nanoribbons were also examined, with high-pressure experiments showing transformations from orthorhombic to cubic and ultimately amorphous states, underscoring their structural resilience and entropic complexity. Overall, this work provides new insight into the structural response of Li2CoO2F and related oxides under extreme conditions, highlighting how fluorination and Li enrichment influence their stability."]},{"key":"dc:title","label":"Title","values":["Study of Functional Complex Oxides at High Pressure-Temperature Conditions"]}]}],"canonical_facts":{"dc:creator":["Husam Farraj (23292013)"],"dc:date":["2025-12-01T00:00:00Z"],"dc:description":["Complex oxides are a diverse family of functional materials whose stability and transformations under extreme conditions are central to chemistry, energy research, and the design of novel compounds. This dissertation focuses on lithium cobalt oxyfluoride (Li2CoO2F), a Li-rich disordered rock-salt cathode, together with other representative complex oxides studied under high pressures and temperatures. Synchrotron X-ray diffraction, Raman spectroscopy, neutron scattering, and first-principles calculations were used to probe the structural response of Li2CoO2F across multiple length scales. These studies reveal how fluorination and Li enrichment promote local spinel-like motifs, stabilize metastable frameworks, and modify the elastic behavior under compression and heating. Complementary work on PbTiO3 demonstrates how kinetic barriers and thermodynamic driving forces combine to stabilize unexpected dissociation products, including a previously unreported PbO polymorph at megabar pressures. High-entropy oxide nanoribbons were also examined, with high-pressure experiments showing transformations from orthorhombic to cubic and ultimately amorphous states, underscoring their structural resilience and entropic complexity. Overall, this work provides new insight into the structural response of Li2CoO2F and related oxides under extreme conditions, highlighting how fluorination and Li enrichment influence their stability."],"dc:identifier":["10.25417/uic.31451635.v1"],"dc:relation":["https://figshare.com/articles/thesis/Study_of_Functional_Complex_Oxides_at_High_Pressure-Temperature_Conditions/31451635"],"dc:rights":["In Copyright","Open Access after 2028-01-01"],"dc:subject":["Chemistry","Inorganic"],"dc:title":["Study of Functional Complex Oxides at High Pressure-Temperature Conditions"],"dc:type":["Text","Thesis"]},"updated_at":"2026-07-27T21:34:29Z"}