Benzaid, AbdelaliBounar, NedjemeddineWhba, RawdahSaoudel, AbdelmalekGuler, MihrihanAltin, Serdar2026-04-042026-04-0420252365-6549https://doi.org/10.1002/slct.202504366https://hdl.handle.net/11616/109935Vanadium-doped sodium manganese oxides (O3-NaMnO2) are promising cathode materials for sodium-ion batteries (SIBs) due to their structural stability and enhanced electrochemical performance. This study systematically investigates the effects of V doping (x = 0.03-0.50) on the structural, morphological, and electrochemical properties of NaMnO2 synthesized via a solid-state method. X-ray diffraction (XRD) confirms that low V doping (x <= 0.10) stabilizes the layered O3 structure and suppresses Jahn-Teller (JT) distortions, while higher doping induces a secondary Na0.5VO2 phase. Scanning and transmission electron microscopy (SEM/TEM) reveal that moderate V substitution (x = 0.10) improves particle uniformity and Na-ion transport. Electrochemical measurements show that both x = 0.03 and x = 0.10 exhibit good performance; however, x = 0.03 provides the best overall balance of high capacity, rate capability, and cycling stability, delivering initial charge and discharge capacities of 211 and 124 mAh/g, respectively. Redox and impedance analyses indicate reduced charge-transfer resistance and enhanced Na-ion kinetics at this composition. In contrast, excessive V doping (x >= 0.30) causes structural degradation and capacity fading. These results highlight the importance of controlled V doping in optimizing NaMnO2-based cathodes for high-performance SIBs.eninfo:eu-repo/semantics/openAccesselectrochemical responsesodium ion batteriessodium manganese oxidestructuralvanadium-dopedArticle104610.1002/slct.2025043662-s2.0-105023977398N/AWOS:001630384100001Q30000-0002-0624-60740000-0002-4590-907X0000-0002-4786-897X