Single-crystal H2V3O8nanowires: a competitive anode with large capacity for aqueous lithium-ion batteries

Abstract

Single-crystal H₂V₃O₈ nanowires with a width of ∼50 nm were fabricated by a facile one-step hydrothermal method and SEM, TEM, TGA, XRD, XPS were used to characterize their morphology and structure details. The possibility of using this material as an anode candidate for aqueous lithium-ion batteries was investigated for the first time. CV and galvanostatic charge/discharge measurements indicated that the intercalation/deintercalation of Li⁺ in this material in aqueous electrolyte is highly reversible. A discharge capacity of 234 mAh g⁻¹ can be obtained for the synthesized H₂V₃O₈ nanowires at the current density of 0.1 A g⁻¹ in aqueous solution of 5 M LiNO₃ and 0.001 M LiOH, much larger than the available capacities (less than 110 mAh g⁻¹) of other vanadium oxides in aqueous electrolyte. Furthermore, the H₂V₃O₈ nanowires can be charge/discharged upon 50 cycles with nearly no capacity loss in organic electrolyte and a capacity retention over 70% in aqueous electrolyte, showing better cycle stability than other vanadium oxide predecessors for aqueous lithium-ion batteries.