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