Reversible multielectron redox activity of the anti-NASICON-type phosphate LiNbV(PO 4 ) 3 towards lithium and sodium intercalation

• Published in: Dalton transactions : an international journal of inorganic chemistry 2024-10, Vol.53 (41), p.16918-16928
• Main Authors: Cherkashchenko, Ilia R, Panin, Rodion V, Dembitskiy, Artem D, Novichkov, Daniil A, Aksyonov, Dmitry A, Antipov, Evgeny V, Khasanova, Nellie R
• Format: Article
• Language: English
• Subjects: Density functional theory; Diffusion barriers; Electrode materials; Intercalation; Ion diffusion; Lithium; Percolation; Sodium; Sol-gel processes
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/d4dt02031f

The LiNbV(PO ) phosphate with the anti-NASICON structure ( = 12.126(1) Å, = 8.6158(4) Å, = 8.6959(6) Å, = 908.5(1) Å , S.G. ) has been synthesized using a Pechini sol-gel process. It exhibits reversible multielectron transitions Li and Na anodes. In a Li half-cell, it supports a 4e transfer due to the activation of the Nb /Nb and V /V 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 and 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(PO ) framework. This study introduces a new approach to improve anti-NASICON-structured electrode materials by utilizing redox transitions of 4d elements for energy storage.