Synthesis of β-LiFe5O8/α-Li2FeO3/α-Fe2O3 from spent lithium iron phosphate battery cathodes for pseudocapacitor applications

Synthesis of β-LiFe5O8/α-Li2FeO3/α-Fe2O3 from spent lithium iron phosphate battery cathodes for pseudocapacitor applications | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Synthesis of β-LiFe 5 O 8 /α-Li 2 FeO 3 /α-Fe 2 O 3 from spent lithium iron phosphate battery cathodes for pseudocapacitor applications R. B. Querubino, E. L. D. Coelho, M. C. Chaves, R. A. Oliveira, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6687717/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 16 You are reading this latest preprint version Abstract In this study, spent lithium iron phosphate (LFP) LIBs from electric vehicles were recycled through hydrometallurgical and pyrometallurgical routes. The spent cathode material was characterized by X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive spectroscopy, scanning electron microscopy (SEM), and inductively coupled plasma optical emission spectrometry. LiFePO 4 , Fe 2 O 3 , and FePO 4 were identified as the predominant phases, and Fe(OH) 3 and Fe 2 (PO 4 )O as secondary phases. Alkaline leaching was found to be effective in recovering lithium and preserving structural components, such as LiFePO 4 . The residue was then used for the synthesis of a novel material. Structural and morphological characterization by XRD, Raman spectroscopy, and SEM revealed a disordered crystalline phase of β-LiFe 5 O 8 /α-Li 2 FeO 3 /α-Fe 2 O 3 with agglomerated grains of irregular particle sizes. The recycled material exhibited pseudocapacitor behavior, with a specific capacitance of 3.0 F g −1 and 82% capacitance retention over 250 charge/discharge cycles at a current density of 0.7 A g −1 showed potential as a pseudocapacitor. lithium-ion battery lithium ferrite pseudocapacitor recycling sustainability Full Text Additional Declarations No competing interests reported. Supplementary Files Fig.S1.tif Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 12 Jul, 2025 Reviewers agreed at journal 08 Jul, 2025 Reviewers agreed at journal 08 Jul, 2025 Reviewers agreed at journal 07 Jul, 2025 Reviews received at journal 05 Jul, 2025 Reviewers agreed at journal 05 Jul, 2025 Reviews received at journal 18 Jun, 2025 Reviewers agreed at journal 06 Jun, 2025 Reviews received at journal 05 Jun, 2025 Reviewers agreed at journal 02 Jun, 2025 Reviewers agreed at journal 01 Jun, 2025 Reviewers agreed at journal 22 May, 2025 Reviewers invited by journal 19 May, 2025 Editor assigned by journal 19 May, 2025 Submission checks completed at journal 19 May, 2025 First submitted to journal 17 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6687717","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":458990959,"identity":"d60c835b-5bc6-4851-8671-6b353483902f","order_by":0,"name":"R. B. 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The spent cathode material was characterized by X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive spectroscopy, scanning electron microscopy (SEM), and inductively coupled plasma optical emission spectrometry. LiFePO\u003csub\u003e4\u003c/sub\u003e, Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, and FePO\u003csub\u003e4\u003c/sub\u003e were identified as the predominant phases, and Fe(OH)\u003csub\u003e3\u003c/sub\u003e and Fe\u003csub\u003e2\u003c/sub\u003e(PO\u003csub\u003e4\u003c/sub\u003e)O as secondary phases. Alkaline leaching was found to be effective in recovering lithium and preserving structural components, such as LiFePO\u003csub\u003e4\u003c/sub\u003e. The residue was then used for the synthesis of a novel material. Structural and morphological characterization by XRD, Raman spectroscopy, and SEM revealed a disordered crystalline phase of β-LiFe\u003csub\u003e5\u003c/sub\u003eO\u003csub\u003e8\u003c/sub\u003e/α-Li\u003csub\u003e2\u003c/sub\u003eFeO\u003csub\u003e3\u003c/sub\u003e/α-Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e with agglomerated grains of irregular particle sizes. The recycled material exhibited pseudocapacitor behavior, with a specific capacitance of 3.0 F g\u003csup\u003e−1\u003c/sup\u003e and 82% capacitance retention over 250 charge/discharge cycles at a current density of 0.7 A g\u003csup\u003e−1\u003c/sup\u003e showed potential as a pseudocapacitor.\u003c/p\u003e","manuscriptTitle":"Synthesis of β-LiFe5O8/α-Li2FeO3/α-Fe2O3 from spent lithium iron phosphate battery cathodes for pseudocapacitor applications","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-21 17:26:16","doi":"10.21203/rs.3.rs-6687717/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-12T13:05:18+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"108460940899282670278085702722587084039","date":"2025-07-08T10:14:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"164051156667327120311416568419774631656","date":"2025-07-08T04:53:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"224309304173708252119824508540515589475","date":"2025-07-07T07:18:55+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-05T13:44:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"74902929193517528384560682899213948481","date":"2025-07-05T11:41:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-18T10:47:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"244363654246582439135299555944384221969","date":"2025-06-06T10:04:05+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-05T07:00:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"34596772181610022958552179068221794266","date":"2025-06-02T06:26:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"141533527064884871917038607926009762387","date":"2025-06-02T01:32:25+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"269028103761741809214056382504901989718","date":"2025-05-22T06:11:38+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-19T18:29:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-19T10:39:51+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-19T10:39:29+00:00","index":"","fulltext":""},{"type":"submitted","content":"Ionics","date":"2025-05-17T14:44:47+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"ionics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":" Learn more about [Ionics](https://www.springer.com/journal/11581) ","snPcode":"11581","submissionUrl":"https://mc.manuscriptcentral.com/ionics","title":"Ionics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ecf9cd6e-38ba-4372-98eb-39a74d3bd5aa","owner":[],"postedDate":"May 21st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-10-22T18:53:19+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-21 17:26:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6687717","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6687717","identity":"rs-6687717","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}