Aragón María J, Lavela Pedro, Ortiz Gregorio F, Alcántara Ricardo, Tirado José L
Departamento de Química Inorgánica e Ingeniería Química, Instituto Universitario de Investigación en Química Fina y Nanoquímica, Universidad de Córdoba , Campus de Rabanales, Edificio Marie Curie, E-14071 Córdoba, Spain.
Inorg Chem. 2017 Oct 2;56(19):11845-11853. doi: 10.1021/acs.inorgchem.7b01846. Epub 2017 Sep 13.
A slight deviation of the stoichiometry has been introduced in NaV(PO) (0 ≤ x ≤ 0.1) samples to determine the effect on the structural and electrochemical behavior as a positive electrode in sodium-ion batteries. X-ray diffraction and XPS results provide evidence for the flexibility of the NASICON framework to allow a limited vanadium superstoichiometry. In particular, the NaV(PO) formula reveals the best electrochemical performance at the highest rate (40C) and capacity retention upon long cycling. It is attributed to the excellent kinetic response and interphase chemical stability upon cycling. The electrochemical performance of this vanadium superstoichiometric sample in a full sodium-ion cell is also described.
