Structure and electrochemistry of K-ion Prussian blue analogues
<p>Rechargeable batteries are the pivotal technology for the electrification of energy and transport infrastructure. Prussian blue analogues (PBAs) are an increasingly prominent family of cathode materials for Na- and K-ion batteries, a cheaper and more sustainable alternative to Li-ion batter...
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| Fformat: | Traethawd Ymchwil |
| Iaith: | English |
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2024
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| _version_ | 1826313766953811968 |
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| author | Cattermull, J |
| author2 | Pasta, M |
| author_facet | Pasta, M Cattermull, J |
| author_sort | Cattermull, J |
| collection | OXFORD |
| description | <p>Rechargeable batteries are the pivotal technology for the electrification of energy and transport infrastructure. Prussian blue analogues (PBAs) are an increasingly prominent family of cathode materials for Na- and K-ion batteries, a cheaper and more sustainable alternative to Li-ion batteries. As molecular framework materials, PBAs are structurally distinct from more established layered oxide or polyanionic cathode materials. Structurally, PBAs are most closely related to perovskites, and as yet it is not clear how PBA electrochemistry relates to other cathode materials from this structural perspective.</p>
<p>The objective of this Thesis is to develop structural models for K-ion PBAs in order to understand their potential as a cathode material for rechargeable batteries. The starting point is to consolidate the present literature to identify what the key structural challenges are for PBAs in the context of the cathode material, K2Mn[Fe(CN)6]. This summary highlights many outstanding research questions, with the prevailing theme being the structural transformations that impact the electrochemistry of the material in question. These structural transformations are related to two separate distortion modes—namely, K-ion slides and Jahn–Teller order. In following the longstanding body of work on distortion modes in perovskites, it is first established what drives distortions in PBAs and what useful tools there might be for predicting their magnitude. K-ion slides are then characterised using variable temperature X-ray diffraction measurements and Monte Carlo simulations. Then, a simple geometric relationship is developed to capture the underlying physics of the slide distortion, paving the way for establishing design rules for controlling it. Next, K2Cu[Fe(CN)6] is targeted as a material for synthesis and both structural and electrochemical characterisation. The objective of that study is to introduce structural complexity to a well-characterised ostensibly ‘simple’ system and then explore the impact on its electrochemical properties. Finally, K2Mn[Fe(CN)6] is studied using operando X-ray techniques to explore the phase transformations that occur on cycling and their impact on the system’s electrochemistry. Comparison with well-known cathode materials sheds light on this poorly understood system, revealing the role of non-equilibrium behaviour in PBAs.</p>
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| first_indexed | 2024-09-25T04:20:13Z |
| format | Thesis |
| id | oxford-uuid:3b97d7e4-c6e7-4ff0-81c9-c321d56608f2 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-09-25T04:20:13Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | oxford-uuid:3b97d7e4-c6e7-4ff0-81c9-c321d56608f22024-08-08T16:24:16ZStructure and electrochemistry of K-ion Prussian blue analoguesThesishttp://purl.org/coar/resource_type/c_db06uuid:3b97d7e4-c6e7-4ff0-81c9-c321d56608f2EnglishHyrax Deposit2024Cattermull, JPasta, MGoodwin, A<p>Rechargeable batteries are the pivotal technology for the electrification of energy and transport infrastructure. Prussian blue analogues (PBAs) are an increasingly prominent family of cathode materials for Na- and K-ion batteries, a cheaper and more sustainable alternative to Li-ion batteries. As molecular framework materials, PBAs are structurally distinct from more established layered oxide or polyanionic cathode materials. Structurally, PBAs are most closely related to perovskites, and as yet it is not clear how PBA electrochemistry relates to other cathode materials from this structural perspective.</p> <p>The objective of this Thesis is to develop structural models for K-ion PBAs in order to understand their potential as a cathode material for rechargeable batteries. The starting point is to consolidate the present literature to identify what the key structural challenges are for PBAs in the context of the cathode material, K2Mn[Fe(CN)6]. This summary highlights many outstanding research questions, with the prevailing theme being the structural transformations that impact the electrochemistry of the material in question. These structural transformations are related to two separate distortion modes—namely, K-ion slides and Jahn–Teller order. In following the longstanding body of work on distortion modes in perovskites, it is first established what drives distortions in PBAs and what useful tools there might be for predicting their magnitude. K-ion slides are then characterised using variable temperature X-ray diffraction measurements and Monte Carlo simulations. Then, a simple geometric relationship is developed to capture the underlying physics of the slide distortion, paving the way for establishing design rules for controlling it. Next, K2Cu[Fe(CN)6] is targeted as a material for synthesis and both structural and electrochemical characterisation. The objective of that study is to introduce structural complexity to a well-characterised ostensibly ‘simple’ system and then explore the impact on its electrochemical properties. Finally, K2Mn[Fe(CN)6] is studied using operando X-ray techniques to explore the phase transformations that occur on cycling and their impact on the system’s electrochemistry. Comparison with well-known cathode materials sheds light on this poorly understood system, revealing the role of non-equilibrium behaviour in PBAs.</p> |
| spellingShingle | Cattermull, J Structure and electrochemistry of K-ion Prussian blue analogues |
| title | Structure and electrochemistry of K-ion Prussian blue analogues |
| title_full | Structure and electrochemistry of K-ion Prussian blue analogues |
| title_fullStr | Structure and electrochemistry of K-ion Prussian blue analogues |
| title_full_unstemmed | Structure and electrochemistry of K-ion Prussian blue analogues |
| title_short | Structure and electrochemistry of K-ion Prussian blue analogues |
| title_sort | structure and electrochemistry of k ion prussian blue analogues |
| work_keys_str_mv | AT cattermullj structureandelectrochemistryofkionprussianblueanalogues |