{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T20:47:38Z","timestamp":1791924458046,"version":"4.3.4"},"reference-count":49,"publisher":"American Chemical Society (ACS)","issue":"40","license":[{"start":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T00:00:00Z","timestamp":1790812800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001843","name":"Science and Engineering Research Board","doi-asserted-by":"publisher","award":["SRG\/2022\/001301"],"award-info":[{"award-number":["SRG\/2022\/001301"]}],"id":[{"id":"10.13039\/501100001843","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100009526","name":"Amrita Vishwa Vidyapeetham University","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100009526","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,13]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>P2-type layered oxides have gained significant attention in energy storage applications due to their superior rate capability and cycling performance. However, P2-type layered oxides suffer from low sodium content and irreversible phase transitions at high voltages, limiting reversible capacity and long-term durability. Although Cu\u2013Mn-based systems offer a high operating voltage through the Cu2+\/Cu3+ redox couple, the accessible voltage window remains narrow, resulting in restricted capacity. In this work, we employ a compositional engineering strategy by introducing Fe into the Cu\u2013Mn framework to enhance both structural stability and redox activity. Fe incorporation enhances structural stability and redox activity by introducing additional cationic redox centers. The synergistic involvement of the Cu2+\/Cu3+ and Fe3+\/Fe4+ redox couples maintains a high average voltage (\u223c3.54 V) while improving electrochemical reversibility. The resulting P2\u2013Na0.7Cu0.3Mn0.6Fe0.1O2 cathode demonstrates a reversible capacity exceeding \u223c90 mAh g\u20131 when combined with CNTs, along with excellent cycling stability. Ex situ XRD analysis reveals reversible phase evolution, confirming enhanced structural robustness during cycling. This study highlights the effectiveness of Fe substitution in optimizing Cu\u2013Mn cathode chemistry, offering a promising pathway for high-energy and durable sodium-ion battery systems.<\/jats:p>","DOI":"10.1021\/acsomega.6c08581","type":"journal-article","created":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T18:01:36Z","timestamp":1790877696000},"page":"62115-62125","source":"Crossref","is-referenced-by-count":0,"title":["Tuning High-Voltage\nCu\u2013Fe Redox in P2-Type\nLayered Metal Oxide Cathodes for Sodium-Ion Batteries"],"prefix":"10.1021","volume":"11","author":[{"given":"Hina","family":"Parappan","sequence":"first","affiliation":[{"name":"Amrita Vishwa Vidyapeetham , , , ,","place":["Kochi, Kerala, India, 682041"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Greeshma","family":"Caroline","sequence":"additional","affiliation":[{"name":"Amrita Vishwa Vidyapeetham , , , ,","place":["Kochi, Kerala, India, 682041"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shantikumar V.","family":"Nair","sequence":"additional","affiliation":[{"name":"Amrita Vishwa Vidyapeetham , , , ,","place":["Kochi, Kerala, India, 682041"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2545-5020","authenticated-orcid":true,"given":"Senthilkumar","family":"Baskar","sequence":"additional","affiliation":[{"name":"Amrita Vishwa Vidyapeetham , , , ,","place":["Kochi, Kerala, India, 682041"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,10,1]]},"reference":[{"key":"2026101315082758600_cit1","doi-asserted-by":"publisher","first-page":"2256","DOI":"10.1038\/s41467-021-22523-3","article-title":"Tuning\nlocal chemistry of P2 layered-oxide cathode for high energy and long\ncycles of sodium-ion battery","volume":"12","author":"Wang","year":"2021","journal-title":"Nat. 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Electrochem. Soc."},{"key":"2026101315082758600_cit8","doi-asserted-by":"publisher","first-page":"2203521","DOI":"10.1002\/aenm.202203521","article-title":"Regulating\nNa occupation in P2-type layered oxide cathode for all-climate sodium-ion\nbatteries","volume":"13","author":"Liu","year":"2023","journal-title":"Adv. Energy Mater."},{"key":"2026101315082758600_cit9","doi-asserted-by":"publisher","first-page":"284","DOI":"10.1021\/acs.accounts.2c00690","article-title":"Layered oxide cathodes for sodium-ion batteries: storage\nmechanism, electrochemistry, and techno-economics","volume":"56","author":"Zuo","year":"2023","journal-title":"Acc. Chem. Res."},{"key":"2026101315082758600_cit10","doi-asserted-by":"publisher","first-page":"1500031","DOI":"10.1002\/advs.201500031","article-title":"Air-stable copper-based\nP2-Na7\/9Cu2\/9Fe1\/9Mn2\/3O2 as a new positive electrode material for sodium-ion\nbatteries","volume":"2","author":"Li","year":"2015","journal-title":"Adv. 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J."},{"key":"2026101315082758600_cit42","doi-asserted-by":"publisher","first-page":"104188","DOI":"10.1016\/j.ensm.2025.104188","article-title":"Fe-rich layered\noxide cathode for sodium-ion batteries enabled by synergistic modulation\nof ion transport and structural stability","volume":"77","author":"Hong","year":"2025","journal-title":"Energy\nStorage Mater."},{"key":"2026101315082758600_cit43","doi-asserted-by":"publisher","first-page":"389","DOI":"10.1016\/j.ensm.2021.11.041","article-title":"Shear-resistant interface of layered oxide cathodes for sodium ion\nbatteries","volume":"45","author":"Huang","year":"2022","journal-title":"Energy Storage Mater."},{"key":"2026101315082758600_cit44","doi-asserted-by":"publisher","first-page":"161239","DOI":"10.1016\/j.cej.2025.161239","article-title":"Preparation and electrochemical\nperformance of Na0. 67Mn0. 67Fe0.\n2Co0. 1Cu0. 03O2 cathode material for sodium-ion batteries","volume":"509","author":"Fengchun","year":"2025","journal-title":"Chem. Eng. J."},{"key":"2026101315082758600_cit45","doi-asserted-by":"publisher","first-page":"2387","DOI":"10.1021\/cm504339y","article-title":"Ordered and disordered\npolymorphs of Na(Ni2\/3Sb1\/3)O2: honeycomb-ordered\ncathodes for Na-ion\nbatteries","volume":"27","author":"Ma","year":"2015","journal-title":"Chem. Mater."},{"key":"2026101315082758600_cit46","doi-asserted-by":"publisher","first-page":"2002199","DOI":"10.1002\/advs.202002199","article-title":"Dual-strategy\nof cation-doping\nand nanoengineering enables fast and stable sodium-ion storage in\na novel Fe\/Mn-based layered oxide cathode","volume":"21","author":"Shen","year":"2020","journal-title":"Adv.\nSci."},{"key":"2026101315082758600_cit47","doi-asserted-by":"publisher","first-page":"6684","DOI":"10.1021\/acs.chemmater.7b01146","article-title":"Structural\nevolution\nand redox processes involved in the electrochemical cycling of P2\u2013Na0.67 [Mn0.66Fe0.20Cu0.14]\nO2","volume":"29","author":"Talaie","year":"2017","journal-title":"Chem. 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