Search

The LiNbV(PO4)3 phosphate with the anti-NASICON structure (a = 12.126(1) Å, b = 8.6158(4) Å, c = 8.6959(6) Å, V = 908.5(1) Å3, S.G. Pbcn) has been synthesized using a Pechini sol–gel process. It exhibits reversible multielectron transitions versus Li and Na anodes. In a Li half-cell, it supports a 4e− transfer due to the activation of the Nb5+/Nb3+ and V4+/V2+ redox couples, being the first example of 4d metal redox transitions within the anti-NASICON framework confirmed by XANES measurements. X-ray diffraction performed in ex situ and operando regimes disclosed a single-phase mechanism of lithium (de)intercalation. In a Na half-cell, the material demonstrates reversible uptake of 2.77 Na+ ions. Density functional theory calculations revealed percolation barriers of ∼0.5–0.7 eV for Na+ hopping, thus supporting the activation of Na+ ion diffusion in the NbV(PO4)3 framework. This study introduces a new approach to improve anti-NASICON-structured electrode materials by utilizing redox transitions of 4d elements for energy storage. [ABSTRACT FROM AUTHOR]