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A facile and scalable strategy, based on a hydrothermal route, has been applied to fabricate potassium vanadate (KVO) nanowires on Ti fabric. The morphology, crystal structure, chemical composition of the prepared sample are tested and presented in detail. When tested as cathode materials for lithium-ion batteries, the flexible KVO electrode has a high reversible capacity of 270 mAh g −1 at a current density of 100 mA g −1 after 300 cycles. Furthermore, the KVO delivers outstanding rate behavior, even at 960 mA g −1 , a reversible capacity as high as 214.1 mAh g −1 can be retained. The superior electrochemical performance suggests that the KVO nanowires on Ti fabric can be as a potential cathode candidate for flexible rechargeable lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• Metallic Co nanoparticles are in-situ deposited into the discharged TiO 2 nanotube array. • After calcination, the resulting TiO 2 @Co composite has excellent ferromagnetic properties. • The maximum saturation magnetization of TiO 2 @Co composite is 15.85 emu/g. Titanium oxide (TiO 2) nanotube array is prepared by an anodization method, and the TiO 2 nanotube array and a lithium foil are used as working and counter electrodes, respectively, to assemble a lithium-ion battery. After discharge to 0.01 V, the TiO 2 nanotube array is reducible. Metallic Co nanoparticles are in-situ deposited into the discharged TiO 2 nanotube array in saturated cobalt acetate in N-N dimethylformamide solution for the first time. The sample exhibits enhanced magnetic properties after calcination at 500 °C in a reducing agent. The morphology, structure and magnetic properties of the samples are characterized and analyzed in detail. This work provides a new method for the synthesis of one-dimensional functional materials by using TiO 2 nanotube array template. [ABSTRACT FROM AUTHOR]

Abstract Manganese vanadate (Mn 2 V 2 O 7) nanosheets on titanium (Ti) foil are synthesized by a cation-exchange method using sodium vanadate nanowires as the precursor. By varying the cation-exchange time in manganese acetate (Mn(CH 3 COO) 2) aqueous solution, the tunable morphologies and chemical components of the samples are tested, compared and presented in detail. The evolution process contains cation-exchange of Mn2+ and Na+, newly generated H+ to dissolve vanadate, and precipitation manganese vanadate nanosheets on the original sodium vanadate nanowire surface. Furthermore, the thermal and crystal properties of the as-prepared nanosheets are evaluated by calcinations at different temperatures. The Mn 2 V 2 O 7 nanosheets obtained at 250 °C, which are used as electrode of lithium-ion battery, have the first discharge capacity of 1048.0 mAh g−1 at 50 mA g−1. After 100 cycles, the residual capacity is more than 800 mAh g−1. Graphical abstract Manganese vanadate nanosheets on titanium foil are successfully assembled using a cation-exchange method for the first time. As an electrode material, it presents good cyclic performance and high charge-discharge capacity. Image 1 Highlights • Manganese vanadate nanosheets are successfully prepared using a cation-exchange method. • Manganese vanadate nanosheets on titanium foil present a high electrochemical performance for lithium ion battery. • The evolution in this work opens a new way to fabricate inorganic vanadates. [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]

Highlights • The β-Na 0.33 V 2 O 5 nanowires were obtained by an electrodeposited-hydrothermal method. • We have synthesized β-Na 0.33 V 2 O 5 nanowire film with high tap density. • The thickness of the β-Na 0.33 V 2 O 5 nanowires is ∼10.5 μm at 5 h, 2.5 V, 90 °C. • The β-Na 0.33 V 2 O 5 @PPy maintains a capacity of 241.7 mAh g−1 after 50 circulations. Abstract A novel electrodeposited-hydrothermal method has been developed to fabricate high-density β-Na 0.33 V 2 O 5 nanowire film on a metal current collector (Ti foil). The morphology, crystal structure, and the effects of deposition voltage, temperature and time on the prepared samples were tested and presented in detail. The thickness of the β-Na 0.33 V 2 O 5 nanowire film was ∼10.5 μm under experimental conditions of 5 h time, 2.5 V voltage, and 90 °C temperature. When the β-Na 0.33 V 2 O 5 nanowire film was coated with polypyrrole and served as a cathode of lithium-ion battery, it exhibited a high reversible discharge capacity of 269.9 mAh g−1 at a current density of 50 mA g−1. By contrast, the cycling behavior of this material is proved to be much better than the bare β-Na 0.33 V 2 O 5 nanowire film. This research provides a new pathway to explore high tap density cathode materials for lithium-ion battery with enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) nanowire arrays have been prepared for the first time using Na5V12O32 nanowires as a sacrificial template. Fourier-transformed infrared spectroscopy and energy-dispersive X-ray spectroscopy were used to characterize the as-prepared PANI nanowire arrays. Further, the electrochemical properties of the PANI nanowire arrays for lithium-ion batteries were investigated with cyclic voltammetry, galvanostatic charge-discharge experiment, and rate performance. It delivered a high discharge capacity of 119.79 mA h g−1 after 100 cycles between 2.0 and 4.0 V at 30 mA g−1. [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]

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]

In order to improve lithium storage capacity and cycle stability of the electrode materials, the combination of the active material and graphene is an effective way. Reduced graphene oxide (rGO) film on Ti substrate is obtained in an aqueous graphene oxide solution using a two-electrode constant voltage electrodeposition system. Then the rGO film on Ti substrate is used as working electrode to assemble lithium-ion batteries and discharged to 0.01 V. The discharged rGO film further reacts with cobalt ions in the cobalt acetate aqueous solution to fabricate the cobalt oxide (CoO)/rGO-precursor, and subsequently the CoO/rGO-700 composite is obtained by calcining the precursor at 700 °C under N 2. Different measurements are conducted to evaluate the samples. The CoO/rGO-700 composites are further used as electrode material of lithium-ion batteries, which deliver an initial capacity of 1290.6 mAh·g−1 at 100 mA·g−1. For the first time, the synthetic method reported in this work can be extended to the synthesis of other metal or oxide/rGO composites. Unlabelled Image • rGO film is successfully prepared by an electrodeposition method. • CoO nanoparticles are anchored on the discharged-graphene film successfully. • The CoO/rGO-700 composites deliver a reversible capacity of 1290.6 mAh·g−1 at 100 mA·g−1. [ABSTRACT FROM AUTHOR]