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Highlights • Na 5 V 12 O 32 nanowire arrays were prepared by a facile hydrothermal method. • The nanowire arrays on titanium foil were used for the first time as a cathode in sodium-ion batteries. • Good initial charge/discharge capacities were 166 and 161 mAh·g−1 at a current density of 30 mA·g−1, respectively. • The electrode retained a reversible capacity of 130 mAh·g−1 after 40 cycles. Abstract Sodium vanadate (Na 5 V 12 O 32 or Na 1.25 V 3 O 8) nanowire arrays have been successfully prepared using a facile hydrothermal method with subsequent calcinations. The nanowire arrays on titanium foil annealed at 250 °C were used as a cathode material for sodium-ion batteries in the range of 2.0–4.0 V, producing initial charge and discharge capacity of 166 and 161 mAh·g−1, respectively. The electrode showed good cycle performance and moderate rate performance. These results indicated that Na 5 V 12 O 32 is a promising material for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Iron vanadate nanowires were firstly synthesized by a cation-exchange routine. • Well-dispersed porous iron vanadate nanowires firmly anchored on Ti foil. • The iron vanadate nanowires exhibit superior lithium storage capability. • The charge-discharge process prefers to pseudocapacitive-controlled behavior. Abstract The nanostructuring of materials can solve the problem of low conductivity of the vanadate electrode, thereby increasing the potential for lithium storage performance. The traditional battery is prepared by coating active materials on current collector, which produces large contact resistance between the current collector and the electrodes, impeding the overall electrochemical performances of the battery. In this work, we propose and verify a scheme for directly loading porous iron vanadate nanowire array electrode on titanium foil. The resultant electrode (the as-prepared iron vanadate annealed at 300 °C) exhibits an enhanced lithium storage performance, the discharge capacity after 100 cycles is 1041.10 mAh·g−1 at a current density of 300 mA·g−1. The iron vanadate nanowire electrode is fabricated by a simple and scalable cation-exchange method, which can be provided for the separate and integrated large-scale industrialization of vanadate electrode materials. [ABSTRACT FROM AUTHOR]

Lithium vanadate nanowires have been electrodeposited onto a titanium (Ti) foil by a direct current electrodeposition without template. The morphology, crystal structure, and the effects of deposition voltage, temperature and time on the prepared samples were tested and presented. The as-prepared lithium vanadate nanowires/Ti composite can be used as electrode for lithium-ion battery. Electrochemical measurements showed that the electrode displayed a specific discharge capacitance as high as 235.1 mAh g −1 after 100 cycles at a current density of 30 mA g −1 . This research provides a new pathway to explore high tap density vanadates nanowires on metals with enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Use of hybridized transition-metal oxides nanostructures with a shell coating show promise for improving the electrochemical performance of sodium-ion batteries. Herein, a novel type of designed sodium vanadate @ polypyrrole (Na 5 V 12 O 32 @PPy) nanocomposites with a synergetic core-shell structure was fabricated using sequential hydrothermal and electrodeposition methods. When the Na 5 V 12 O 32 @PPy nanocomposites were employed as a cathode, the assembled sodium-ion batteries exhibited a high reversible discharge capacity of 213 mAh g −1 at a current density of 30 mA g −1 , high rate performance (133 mAh g −1 at 480 mA g −1 ) and superior cycling performance (202 mAh g −1 at 100 mA g −1 after 100 cycles with a capacity retention of 94%). By contrast, the cycling behavior of this novel material proved to be much better than the naked Na 5 V 12 O 32 nanowires. This research provides a new pathway to explore cathode materials for sodium-ion battery with enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Ammonium vanadate (NH 4 V 4 O 10 ) nanowire flowers and nanowires on titanium (Ti) foils are synthesized by hexamethylenetetramine (HMTA)-assisted hydrothermal reactions as a cathode material for lithium-ion battery. The as-prepared NH 4 V 4 O 10 nanowires are about 50 nm in diameter and several micrometers in length. The effects of reaction time, temperature and additive concentration on the resulting morphology are investigated. Reversible lithium intercalation behavior of the nanowires has been evaluated by cyclic voltammetry and galvanostatic discharge–charge cycling. The NH 4 V 4 O 10 nanowires on Ti foil deliver a high discharge capacity of 168.5 mA h g −1 after 100 cycles between 2.0 and 4.0 V at 50 mA g −1 . A high rate capability is obtained with a remaining discharge capacity of about 182.6 mA h g −1 after 35 cycles at various rates. Further, the NH 4 V 4 O 10 nanowires on Ti foil have a higher discharge capacity of 330.5 mA h g −1 after 100 cycles at 0.8–4.0 V at 50 mA g −1 . [ABSTRACT FROM AUTHOR]