{"id":{"repo_id":"cambridge","oai_identifier":"oai:www.repository.cam.ac.uk:1810/344422"},"canonical_url":"https://search.dev.ndltd.org/etd/cambridge/oai:www.repository.cam.ac.uk:1810/344422","repository":{"repo_id":"cambridge","name":"Cambridge University","base_url":"https://api.repository.cam.ac.uk/server/oai/request"},"display":{"title":"Understanding Transition Metal Dissolution from Battery Materials with Solution NMR Methods","abstract":"Rechargeable batteries are a critical modern technology, with widespread and growing use in consumer electronics, transport, and grid energy storage. Lithium-ion batteries commonly use lithium transition metal oxides as cathode materials, many of which can undergo dissolution of the transition metal(s) into the electrolyte solution. Transition metal dissolution can lead to cathode restructuring, electrolyte degradation, thickening of the anode solid electrolyte interphase, and loss of lithium from the active lithium inventory, ultimately causing battery capacity loss. It is generally accepted that dissolved transition metals (e.g., Mn²⁺, Ni²⁺, Co²⁺) are paramagnetic. In NMR measurements, paramagnetic solutes can significantly affect the peak positions and relaxation rates of nearby chemical species in solution. This work therefore explores the use of solution NMR to characterise and quantify transition metal dissolution in battery electrolytes. ¹H, ¹⁹F, ³¹P, and ⁷Li NMR measurements are performed on LiPF₆ solutions containing model transition metal compounds or metals dissolved from cathode materials. NMR of transition metal-contaminated battery electrolyte solutions is used to quantify dissolved metals at micromolar concentrations; determine their oxidation states, spin states, and coordination numbers; and understand the solvation shell in pristine and degraded electrolyte solutions. Specifically, it is shown that Mn²⁺ and Ni²⁺ coordinate primarily to ethylene carbonate in pristine electrolyte solutions, and to difluorophosphate (or other fluorophosphate species) in degraded electrolyte solutions. Sufficient transition metal coordination to fluorophosphate degradation products can induce severe signal broadening, rendering these species undetectable by ¹⁹F and ³¹P NMR, but this issue can be mitigated with the use of suitable coordinating solvents or precipitation agents. This work demonstrates the broad capabilities of easily accessible solution NMR measurements towards elucidating transition metal dissolution-migration-deposition mechanisms. The methods explored in this work may further be applied to any battery chemistry with dissolved paramagnetic species, including sodium-ion, potassium-ion, multivalent, and redox flow chemistries.","abstract_html":"Rechargeable batteries are a critical modern technology, with widespread and growing use in consumer electronics, transport, and grid energy storage. Lithium-ion batteries commonly use lithium transition metal oxides as cathode materials, many of which can undergo dissolution of the transition metal(s) into the electrolyte solution. Transition metal dissolution can lead to cathode restructuring, electrolyte degradation, thickening of the anode solid electrolyte interphase, and loss of lithium from the active lithium inventory, ultimately causing battery capacity loss. It is generally accepted that dissolved transition metals (e.g., Mn²⁺, Ni²⁺, Co²⁺) are paramagnetic. In NMR measurements, paramagnetic solutes can significantly affect the peak positions and relaxation rates of nearby chemical species in solution. This work therefore explores the use of solution NMR to characterise and quantify transition metal dissolution in battery electrolytes. ¹H, ¹⁹F, ³¹P, and ⁷Li NMR measurements are performed on LiPF₆ solutions containing model transition metal compounds or metals dissolved from cathode materials. NMR of transition metal-contaminated battery electrolyte solutions is used to quantify dissolved metals at micromolar concentrations; determine their oxidation states, spin states, and coordination numbers; and understand the solvation shell in pristine and degraded electrolyte solutions. Specifically, it is shown that Mn²⁺ and Ni²⁺ coordinate primarily to ethylene carbonate in pristine electrolyte solutions, and to difluorophosphate (or other fluorophosphate species) in degraded electrolyte solutions. Sufficient transition metal coordination to fluorophosphate degradation products can induce severe signal broadening, rendering these species undetectable by ¹⁹F and ³¹P NMR, but this issue can be mitigated with the use of suitable coordinating solvents or precipitation agents. This work demonstrates the broad capabilities of easily accessible solution NMR measurements towards elucidating transition metal dissolution-migration-deposition mechanisms. The methods explored in this work may further be applied to any battery chemistry with dissolved paramagnetic species, including sodium-ion, potassium-ion, multivalent, and redox flow chemistries.","abstract_has_math":false,"creators":["Allen, Jennifer"],"institution":"University of Cambridge","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Grey, Clare"],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-09-01","date_published":"2022-09-01","updated_at":"2026-07-22T22:24:08Z","subjects":["lithium-ion batteries","transition metal dissolution","solution NMR","paramagnetic NMR"],"languages":["eng"],"rights":[],"rights_urls":["https://www.rioxx.net/licenses/all-rights-reserved/"],"identifier_entries":[{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["0000000298009382"],"render_values":[{"text":"0000-0002-9800-9382","href":"https://orcid.org/0000-0002-9800-9382","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.17863/CAM.91844","outbound_label":"DOI","outbound_source":"dc:identifier.doi"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Grey, Clare"]},{"key":"dc:creator","label":"Author","values":["Allen, Jennifer"]},{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["0000000298009382"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2022-09-01"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cambridge"]},{"key":"dc:relation.isreferencedby.uri","label":"Dc Relation Isreferencedby URI","values":["https://www.repository.cam.ac.uk/handle/1810/344422"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["lithium-ion batteries","transition metal dissolution","solution NMR","paramagnetic NMR"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["https://www.rioxx.net/licenses/all-rights-reserved/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.17863/CAM.91844"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/c51955de-7c4a-4894-b54f-291d8e3212a2/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Rechargeable batteries are a critical modern technology, with widespread and growing use in consumer electronics, transport, and grid energy storage. Lithium-ion batteries commonly use lithium transition metal oxides as cathode materials, many of which can undergo dissolution of the transition metal(s) into the electrolyte solution. Transition metal dissolution can lead to cathode restructuring, electrolyte degradation, thickening of the anode solid electrolyte interphase, and loss of lithium from the active lithium inventory, ultimately causing battery capacity loss. It is generally accepted that dissolved transition metals (e.g., Mn²⁺, Ni²⁺, Co²⁺) are paramagnetic. In NMR measurements, paramagnetic solutes can significantly affect the peak positions and relaxation rates of nearby chemical species in solution. This work therefore explores the use of solution NMR to characterise and quantify transition metal dissolution in battery electrolytes. ¹H, ¹⁹F, ³¹P, and ⁷Li NMR measurements are performed on LiPF₆ solutions containing model transition metal compounds or metals dissolved from cathode materials. NMR of transition metal-contaminated battery electrolyte solutions is used to quantify dissolved metals at micromolar concentrations; determine their oxidation states, spin states, and coordination numbers; and understand the solvation shell in pristine and degraded electrolyte solutions. Specifically, it is shown that Mn²⁺ and Ni²⁺ coordinate primarily to ethylene carbonate in pristine electrolyte solutions, and to difluorophosphate (or other fluorophosphate species) in degraded electrolyte solutions. Sufficient transition metal coordination to fluorophosphate degradation products can induce severe signal broadening, rendering these species undetectable by ¹⁹F and ³¹P NMR, but this issue can be mitigated with the use of suitable coordinating solvents or precipitation agents. This work demonstrates the broad capabilities of easily accessible solution NMR measurements towards elucidating transition metal dissolution-migration-deposition mechanisms. The methods explored in this work may further be applied to any battery chemistry with dissolved paramagnetic species, including sodium-ion, potassium-ion, multivalent, and redox flow chemistries."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["f4e1eef5e3eb4fa145972db10f8f28e7"]},{"key":"dc:title","label":"Title","values":["Understanding Transition Metal Dissolution from Battery Materials with Solution NMR Methods"]}]}],"canonical_facts":{"dc:contributor.advisor":["Grey, Clare"],"dc:creator":["Allen, Jennifer"],"dc:creator.authoridentifier":["0000000298009382"],"dc:date.issued":["2022-09-01"],"dc:description.abstract":["Rechargeable batteries are a critical modern technology, with widespread and growing use in consumer electronics, transport, and grid energy storage. Lithium-ion batteries commonly use lithium transition metal oxides as cathode materials, many of which can undergo dissolution of the transition metal(s) into the electrolyte solution. Transition metal dissolution can lead to cathode restructuring, electrolyte degradation, thickening of the anode solid electrolyte interphase, and loss of lithium from the active lithium inventory, ultimately causing battery capacity loss. It is generally accepted that dissolved transition metals (e.g., Mn²⁺, Ni²⁺, Co²⁺) are paramagnetic. In NMR measurements, paramagnetic solutes can significantly affect the peak positions and relaxation rates of nearby chemical species in solution. This work therefore explores the use of solution NMR to characterise and quantify transition metal dissolution in battery electrolytes. ¹H, ¹⁹F, ³¹P, and ⁷Li NMR measurements are performed on LiPF₆ solutions containing model transition metal compounds or metals dissolved from cathode materials. NMR of transition metal-contaminated battery electrolyte solutions is used to quantify dissolved metals at micromolar concentrations; determine their oxidation states, spin states, and coordination numbers; and understand the solvation shell in pristine and degraded electrolyte solutions. Specifically, it is shown that Mn²⁺ and Ni²⁺ coordinate primarily to ethylene carbonate in pristine electrolyte solutions, and to difluorophosphate (or other fluorophosphate species) in degraded electrolyte solutions. Sufficient transition metal coordination to fluorophosphate degradation products can induce severe signal broadening, rendering these species undetectable by ¹⁹F and ³¹P NMR, but this issue can be mitigated with the use of suitable coordinating solvents or precipitation agents. This work demonstrates the broad capabilities of easily accessible solution NMR measurements towards elucidating transition metal dissolution-migration-deposition mechanisms. The methods explored in this work may further be applied to any battery chemistry with dissolved paramagnetic species, including sodium-ion, potassium-ion, multivalent, and redox flow chemistries."],"dc:format.checksum.md5":["f4e1eef5e3eb4fa145972db10f8f28e7"],"dc:identifier.doi":["10.17863/CAM.91844"],"dc:identifier.uri":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/c51955de-7c4a-4894-b54f-291d8e3212a2/download"],"dc:language":["eng"],"dc:publisher.institution":["University of Cambridge"],"dc:relation.isreferencedby.uri":["https://www.repository.cam.ac.uk/handle/1810/344422"],"dc:rights":["https://www.rioxx.net/licenses/all-rights-reserved/"],"dc:subject":["lithium-ion batteries","transition metal dissolution","solution NMR","paramagnetic NMR"],"dc:title":["Understanding Transition Metal Dissolution from Battery Materials with Solution NMR Methods"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-22T22:24:08Z"}