ABSTRACT
In this work, three-dimensional (3D) TiO2 nanotubes (NTs) on carbon cloth (CC) (TiO2 NTs/CC) were synthesized by a method involving formation of a ZnO@TiO2 nanorod (NRs) on CC (ZnO@TiO2 NRs/CC) structure and a subsequent chemical etching process for ZnO NRs template. The 3D TiO2 NTs/CC were applied as flexible anodes for sodium ion batteries (SIBs). The TiO2 NTs/CC yielded high specific capacity and good cycling stability, superior to that of some reported TiO2 nanocomposites. The TiO2 NTs/CC delivered a reversible capacity of 260 mA·h·g-1 and 85.1% capacity retention over 150 cycles at current density of 0.25 C (1 C = 335 mA·g-1). It also exhibited high rate capacity of 200 mA·h·g-1 at 0.5 C. Even at a high rate of 1.0 C, the TiO2 NTs/CC can still maintain a high capacity of 100 mA·h·g-1. Moreover, it was observed that the electrochemical performance for the TiO2 NTs/CC was much better than that (150 mA·h·g-1 for up to 150 cycles) of a solid TiO2 NRs/CC counterpart, which also demonstrated the capacity enhancement and good cycling stability.
ABSTRACT
The new demands for energy storage systems have been placed with demands for flexible wearable electronics. Herein, rugby-like GeO2 nanoparticles (NPs) have been directly grown on carbon cloth (GeO2 NPs/CC) through a one-step hydrolysis process at room temperature, which can be used as a self-supporting flexible anode for lithium ion battery (LIBs). The rugby-like GeO2 NPs/CC showed an improved lithium-storage performance with features of high reversible capacity ~2000 mA·h·g-1 even after 100 cycles and good cycling stability. Besides, its initial coulomb efficiency (79.1%) was also enhanced compared to that of some reported GeO2-based materials.
ABSTRACT
Controlled synthesis of well-shaped nanocrystals is of significant importance to understand the surface-related properties. Herein, hierarchical Bi2WO6 particles with different morphologies, such as flower-like and pancake-like morphologies were selectively prepared using a simple fluoride ion-assisted hydrothermal process. Morphological modulation of the samples could be easily realized by controlling the initial amount of NH4F. The effect of NH4F as well as the formation mechanism of these Bi2WO6 hierarchical structures were systematically investigated. The morphological control of the final products are proved to be a kinetic control of the reaction, which is closely related to the concentration of fluoride ion in the solution. The as-obtained hierarchical Bi2WO6 particles exhibit different visible-light-driven photo-catalytic activities for the degradation of Rhodamine-B (RhB). The differences in photo-catalytic activities among the as-obtained samples are associated the surface adsorption properties, which result from the synthetic conditions.
