Search

Tin (Sn) is one of the promising anode candidates for next generation applications in lithium ion batteries with high energy densities, but it suffers from drastic volume change (about 260%) upon lithiation. To address this issue, herein an efficient method is reported for coating Sn nanowires with an amorphous Al2O3 layer (Sn-Al2O3) based on a combination of mechanical pressure injection technique and partial dissolution of the anodic aluminum oxide template. Further, the Sn nanowires coated with Al2O3 are dispersed into carbon matrix (Sn-Al2O3-C) by ball milling. In this structure, Al2O3 helps to maintain structural integrity during charge-discharge process, and the introduced carbon matrix enhances electronic conductivity of the overall electrode. As a result, the Sn-Al2O3-C nanocomposite exhibits an enhanced cyclic and rate performance, namely, retaining the capacities of 1308.8 mAh g−1 at the current density of 30 mA g−1 after 20 cycles, 1063.3 mAh g−1 at the current density of 200 mA g−1, and 834.2 mAh g−1 at the current density of 500 mA g−1 after 100 cycles. [ABSTRACT FROM AUTHOR]

Nanosheets-based ZnO-NiO microspheres were synthesized by a simple hydrothermal route combined with subsequent heat treatment at moderate temperature. The physical properties of the resulting samples were characterized by scanning electron microscopy, transmission electron microscope, and X-ray diffraction, respectively. The results show that composite materials, nanosheets-based ZnO-NiO microspheres have been successfully synthesized. For comparison, nanosheets-based ZnO or NiO microspheres were also prepared in the similar method. The nanosheets-based ZnO-NiO microspheres obtained after annealing at 500 °C showed a remarkable composite effect, delivering a higher discharge capacity (733 mAh g at 100 mA g after 50 cycles) and excellent cycling stability in comparison to those of single ZnO or NiO nanosheets. These findings make ZnO-NiO microspheres promising anodes for lithium-ion batteries. The results of this study also offer possibilities of improving the lithium storage capacity of transition metal oxides by controlling both architecture and composition. [ABSTRACT FROM AUTHOR]

With a theoretically high capacity and suitable discharge/charge plateaus, lithium vanadates (such as Li 0.04 V 2 O 5 ) can be used as cathode material for lithium ion batteries. Herein, Li 0.04 V 2 O 5 nanowires are densely anchored onto reduced graphene oxide (rGO) nanosheets to form a Li 0.04 V 2 O 5 @rGO nanocomposite by a hydrothermal method with subsequent thermal treatment. Due to this unique structure, the Li 0.04 V 2 O 5 @rGO exhibits remarkable rate performance and excellent cycling stability. Specifically, it delivers a reversible discharge capacity of 738.09 mA h g −1 at a current density of 100 mA g −1 in the voltage range of 2.0–4.0 V. After 500 cycles, it still maintains a high capacity of 731.70 mA h g −1 , which represents 95.01% retention of the original reversible capacity. These results indicate that the Li 0.04 V 2 O 5 @rGO could be a promising candidate as cathode active material for long-term cycling performance in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

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]

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]

This paper reports a study on the electrochemical performance of vanadium trioxide (V 2 O 3 ) nanowire arrays as a cathode material for Li-ion battery. V 2 O 3 nanowire arrays are formed via thermal treatment of ammonium vanadium bronze (NH 4 V 4 O 10 ) nanowires in a 5% H 2 and 95% Ar atmosphere. X-ray diffraction confirms the thermal reduction. The V 2 O 3 nanowire arrays as an electrode of lithium-ion battery exhibit high reversible capacity and excellent long-term cycling stability. The discharge capacity increases from 243 to 428 mA h g −1 at the first 20 cycles. After 100 cycles, a stable capacity of 444 mA h g −1 is retained at a current density of 30 mA g −1 . [ABSTRACT FROM AUTHOR]