{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/102931"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/102931","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Molecular dynamics simulation and neutron scattering studies of nonaqueous electrolyte solutions","abstract":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-12-01","abstract_html":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-12-01","abstract_has_math":false,"creators":["Li, Zhixia"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Nuclear, Plasma, Radiolgc Engr","degree_department":null,"school":null,"contributors":["Zhang, Yang","Kozlowski, Tomasz"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-02-08T18:43:48Z","date_published":"2019-02-08T18:43:48Z","updated_at":"2026-07-22T22:24:42Z","subjects":["Molecular Dynamics Simulation","Neutron Scattering","Redox flow battery","Nonaqueous electrolyte solutions"],"languages":["en"],"rights":["Copyright 2018 Zhixia Li"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/102931","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Zhang, Yang","Kozlowski, Tomasz"]},{"key":"dc:creator","label":"Author","values":["Li, Zhixia"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-02-08T18:43:48Z","2021-02-09T10:15:12Z","2018-12-03","2018-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear, Plasma, Radiolgc Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Molecular Dynamics Simulation","Neutron Scattering","Redox flow battery","Nonaqueous electrolyte solutions"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2018 Zhixia Li"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/102931"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-12-01","The student, Zhixia Li, accepted the attached license on 2018-12-03 at 12:21.","The student, Zhixia Li, submitted this Thesis for approval on 2018-12-03 at 12:29.","Nonaqueous electrolyte solutions have been widely investigated for a variety of applications due to their outstanding properties such as high conductivity and excellent stability. However, establishment of predictive models for nonaqueous electrolytes remains challenging. Molecular packing and clustering effects in complex liquid systems such as redox-active electrolyte solutions are still poorly understood especially at high concentrations. Here, neutron scattering is used to probe the dynamics at molecular level in nonaqueous organic electrolytes over a wide temperature range. Two model solution systems were chosen: one containing highly symmetric electrolyte molecules prone to crystallization and one containing a de-symmetrized liquid electrolyte preferring disordered states. In the latter case, complete supercooling (preservation of a disordered state below the melting point without crystallization) was observed to very low temperatures at high concentrations. However, upon heating, localized cold crystallization occurs, leading to a burst nucleation of microcrystalline solids within liquid-like components. Our findings indicate the clustering in these materials and point out limits in solvation and molecular crowding in concentrated nonaqueous electrolyte fluids. Although molecular dynamics (MD) simulation is promising method to predict numerous properties of nonaqueous electrolytes, quantitative predictions depend critically on the prescribed force fields. We show that several quantum-mechanically refined force fields for the lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) - acetonitrile electrolyte yield structures agreeing well with the experimental neutron pair distribution function (PDF), yet produce dramatically different dynamics disagreeing with NMR measurements. Such glaring discrepancies indicate that inadequate representation of long-range interactions leads to excessive frustration in the free energy landscape. Better agreement is achieved by proportionally scaling down the atomic charges of the ions. This simplification enabled the simulation of concentration dependences of ionic diffusion for 0.2-2 M LiTFSI solutions without sacrificing fit quality of the PDFs. We argue that not only structures but also dynamics constitute important checkpoints towards to computationally design functional electrolytes.","This Thesis was approved for publication on 2018-12-03 at 13:39.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13178 on 2019-02-08 at 11:40:48","Made available in DSpace on 2019-02-08T18:43:48Z (GMT). No. of bitstreams: 2 LI-THESIS-2018.pdf: 22797043 bytes, checksum: bb7936a38e6c5d77a41221665a1f245f (MD5) LICENSE.txt: 4206 bytes, checksum: 22395e949d336f44b05816ff482926e2 (MD5) Previous issue date: 2018-12-03","Embargo set by: Seth Robbins for item 109958 Lift date: 2021-02-08T18:43:54Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 109958 Lift date: 2021-02-08T18:44:50Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 109958 on 2021-02-09T10:15:12Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Molecular dynamics simulation and neutron scattering studies of nonaqueous electrolyte solutions"]}]}],"canonical_facts":{"dc:contributor":["Zhang, Yang","Kozlowski, Tomasz"],"dc:creator":["Li, Zhixia"],"dc:date":["2019-02-08T18:43:48Z","2021-02-09T10:15:12Z","2018-12-03","2018-12"],"dc:description":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-12-01","The student, Zhixia Li, accepted the attached license on 2018-12-03 at 12:21.","The student, Zhixia Li, submitted this Thesis for approval on 2018-12-03 at 12:29.","Nonaqueous electrolyte solutions have been widely investigated for a variety of applications due to their outstanding properties such as high conductivity and excellent stability. However, establishment of predictive models for nonaqueous electrolytes remains challenging. Molecular packing and clustering effects in complex liquid systems such as redox-active electrolyte solutions are still poorly understood especially at high concentrations. Here, neutron scattering is used to probe the dynamics at molecular level in nonaqueous organic electrolytes over a wide temperature range. Two model solution systems were chosen: one containing highly symmetric electrolyte molecules prone to crystallization and one containing a de-symmetrized liquid electrolyte preferring disordered states. In the latter case, complete supercooling (preservation of a disordered state below the melting point without crystallization) was observed to very low temperatures at high concentrations. However, upon heating, localized cold crystallization occurs, leading to a burst nucleation of microcrystalline solids within liquid-like components. Our findings indicate the clustering in these materials and point out limits in solvation and molecular crowding in concentrated nonaqueous electrolyte fluids. Although molecular dynamics (MD) simulation is promising method to predict numerous properties of nonaqueous electrolytes, quantitative predictions depend critically on the prescribed force fields. We show that several quantum-mechanically refined force fields for the lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) - acetonitrile electrolyte yield structures agreeing well with the experimental neutron pair distribution function (PDF), yet produce dramatically different dynamics disagreeing with NMR measurements. Such glaring discrepancies indicate that inadequate representation of long-range interactions leads to excessive frustration in the free energy landscape. Better agreement is achieved by proportionally scaling down the atomic charges of the ions. This simplification enabled the simulation of concentration dependences of ionic diffusion for 0.2-2 M LiTFSI solutions without sacrificing fit quality of the PDFs. We argue that not only structures but also dynamics constitute important checkpoints towards to computationally design functional electrolytes.","This Thesis was approved for publication on 2018-12-03 at 13:39.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13178 on 2019-02-08 at 11:40:48","Made available in DSpace on 2019-02-08T18:43:48Z (GMT). No. of bitstreams: 2 LI-THESIS-2018.pdf: 22797043 bytes, checksum: bb7936a38e6c5d77a41221665a1f245f (MD5) LICENSE.txt: 4206 bytes, checksum: 22395e949d336f44b05816ff482926e2 (MD5) Previous issue date: 2018-12-03","Embargo set by: Seth Robbins for item 109958 Lift date: 2021-02-08T18:43:54Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 109958 Lift date: 2021-02-08T18:44:50Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 109958 on 2021-02-09T10:15:12Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/102931"],"dc:language":["en"],"dc:rights":["Copyright 2018 Zhixia Li"],"dc:subject":["Molecular Dynamics Simulation","Neutron Scattering","Redox flow battery","Nonaqueous electrolyte solutions"],"dc:title":["Molecular dynamics simulation and neutron scattering studies of nonaqueous electrolyte solutions"],"dc:type":["text"],"thesis:degree_discipline":["Nuclear, Plasma, Radiolgc Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:42Z"}