Composite of K-doped (NH4)2V3O8/graphene as an anode material for sodium-ion batteries

Abstract

A layer structured K-doped (NH₄)₂V₃O₈/graphene (K-NVG) was prepared via a hydrothermal route and then used as an anode material for sodium-ion batteries for the first time. The K-NVG nanosheets have a diameter in the range of 200–500 nm. The K-NVG electrode exhibited stable cycling and a good rate performance with a reversible capacity of 235.4 mA h g⁻¹, which is much higher than the 90.5 mA h g⁻¹ value of the (NH₄)₂V₃O₈/graphene electrode after 100 cycles at a current density of 100 mA g⁻¹. Simultaneously, the retention rate was maintained at 82% even after 250 cycles at the current density of 300 mA g⁻¹. Such good electrochemical properties may be attributed to the K-NVG's stable layered structure.