β‑NaVP2O7 as a Superior Electrode Material for Na-Ion Batteries

• Published in: Chemistry of materials 2019-09, Vol.31 (18), p.7463-7469
• Main Authors: Drozhzhin, Oleg A, Tertov, Ilya V, Alekseeva, Anastasia M, Aksyonov, Dmitry A, Stevenson, Keith J, Abakumov, Artem M, Antipov, Evgeny V
• Format: Article
• Language: English
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.9b02124

The feasibility of sodium-ion batteries as an alternative to lithium-ion batteries in large-scale storage systems largely depends on the availability of advanced electrode materials leading to enhanced energy density and operational sustainability. Herein, we present a novel β-polymorph of sodium vanadium pyrophosphate NaVP2O7 with the KAlP2O7-type structure obtained via hydrothermal synthesis and further thermal dehydration of a hydrophosphate intermediate. β-NaVP2O7 demonstrates attractive electrochemical behavior as a Na-ion positive electrode (cathode) material with practically achieved a reversible capacity of 104 mAh/g at C/10 current density, an average operating voltage of 3.9 V vs Na/Na+, and only 0.5% volume change between the charged and the discharged states. Electrode material exhibits excellent C-rate capability and cycling stability, providing a capacity of 90 mAh/g at 20C discharge rate and