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oai:figshare.com:article/34033219 2026-09-30T14:38:00Z category_1 category_4 category_915 category_7 category_8 category_12 category_14 category_16 category_24 category_873 category_39 category_62 category_128 category_132 category_133 portal_63 item_type_6 month_year_09_2026

Na-Ion Interstitial Site Filling and Structural Evolution in a Tunnel-Structured Vanadium Oxide Insertion Host James Pérez-Vázquez (25144489) Sarbajeet Chakraborty (20383466) Yu-Hsiang Chiang (15440352) Aysan A. Yilmaz (25144492) Victor A. Gomez (25144495) Yuting Luo (1465735) Leonardo Gobbato (25144498) David A. Santos (12456663) Cade Alaniz (25144501) Denis Sheptyakov (1467583) Grigory Smolentsev (1276212) Olga Safonova (2311387) Maarten Nachtegaal (1275900) Mohammed Al-Hashimi (1553671) Sarbajit Banerjee (1270044) Diana Quintero-Castro (23219509) Dominika Baster (8601045) Biophysics Biochemistry Physical Sciences not elsewhere classified Medicine Microbiology Cell Biology Molecular Biology Physiology Evolutionary Biology Chemical Sciences not elsewhere classified Ecology Marine Biology Hematology Infectious Diseases Plant Biology recovered upon desodiation first discharge process establish design principles demonstrates distinct differences c sites concomitant ex situ </ promising insertion host coordinate β sites reversible structural distortions topochemical sodium insertion 5 </ sub 2 </ sub contrast ion insertion mechanisms governing na operando </ ion insertion β ′, sodium storage structural evolution sodiation mechanisms migration mechanisms type cathodes thereby pillaring reversibly insert rare opportunity neutron scattering multivalent ions larger size ion storage ion stoichiometries ion redistribution ion mobility ion batteries electrochemical measurements combine single approximately 0 The tunnel-structured metastable polymorph ζ-V₂O₅ has emerged as a promising insertion host for alkali and multivalent ions, yet the mechanisms governing Na-ion storage remain poorly understood. Here, we combine single-crystal and powder, <i>operando</i> X-ray diffraction, neutron scattering, and <i>ex situ</i> X-ray absorption spectroscopy techniques with electrochemical measurements to elucidate Na-ion insertion and structural evolution in ζ-V₂O₅. Topochemical sodium insertion is limited to approximately 0.27 Na per formula unit, with Na ions initially occupying split seven-coordinate β sites while preserving the tunnel framework. Electrochemical sodiation accesses higher Na-ion stoichiometries and reveals a sequential filling mechanism involving β, β′, and C sites concomitant with Na-ion redistribution and reversible structural distortions. Despite the larger size of Na ions in comparison to Li ions, the tunnel framework remains intact throughout cycling and is recovered upon desodiation. <i>Operando</i> diffraction and X-ray absorption spectroscopy reveal that approximately 0.3 Na per formula unit remains trapped after the first discharge process, thereby pillaring and stabilizing the framework. The preinserted pillared phase enables subsequent reversible Na-ion storage. The ability to reversibly insert both Li and Na ions in ζ-V₂O₅ provides the rare opportunity to contrast ion insertion and migration mechanisms. Comparison of lithiation and sodiation mechanisms in ζ-V₂O₅ demonstrates distinct differences in the thermodynamics and kinetics of ion insertion despite similar insertion sites and ion mobility. These findings provide mechanistic understanding of sodium storage in metastable ζ-V₂O₅ and establish design principles for robust tunnel-type cathodes for Na-ion and dual-ion batteries. 2026-09-30T00:00:00Z Text Journal contribution 10.1021/acsmaterialsau.6c00206.s003 https://figshare.com/articles/journal_contribution/Na-Ion_Interstitial_Site_Filling_and_Structural_Evolution_in_a_Tunnel-Structured_Vanadium_Oxide_Insertion_Host/34033219 CC BY-NC 4.0