H.M. Wu

Size and morphology effects of ZnO anode nanomaterials for Zn/Ni secondary batteries

ZnO nanoparticles and nanorods as anode active materials were investigated by charge?discharge cycle measurements. The ZnO nanomaterials with larger specific surface area exhibited higher electrochemical activity than conventional ZnO particles. The discharge capacity delivered by ZnO nanorods exceeded 500?mA?h?g?1 until the 175th cycle. It also exhibited higher midpoint discharge voltage than conventional ZnO. The morphologies of ZnO had a significant effect on the electrochemical properties of the anodes. In the initial cycles, the morphologies of ZnO did not essentially change due to the extension effect, and the electrochemical performance of the electrodes was relatively stable. When increasing the cycles, according to the texture growth mechanism, the large flaky ZnO parallel to the substrate surface predominated to reduce the electrochemical performance. Due to the intensive extension effect, the growth mode of ZnO nanorods changed. The eventual morphology was erect small flaky ZnO crystals that suppressed the production of Zn dendrite and enhanced the capacity maintenance.

Electrodeposited Growth Habit and Growth Mechanism of ZnO as Anode Material of Secondary Alkaline Zn Battery

The process of morphology evolution of ZnO nanorod, nanoparticle, and conventional ZnO as anode materials of secondary Zn battery on the charge-discharge cycling were investigated. ZnO with different morphology and particle size showed different electrodeposited growth habit, including the morphology retention on the initial stage and the formation of lamellar ZnO on the subsequent stage, which resulted in the different electrochemical performance of ZnO. The material utilization of ZnO nanorod and nanoparticle surpassed the conventional ZnO. Epitaxial growth and texture growth were proposed to illuminate the electrodeposited growth habit of ZnO. The epitaxial growth resulted from the influence of the substrate and led to the morphology retention of ZnO nanorod and nanoparticle. The texture growth was mainly influenced by the crystal structure, substrate, current density, etc., including the lateral and outward growth models. The Zn dendrites were the results of preferential growth of some lamellar ZnO, associated with the orientation and the surface protrusion of the lamellar ZnO.

Effect of LiCoO2 coating on the electrochemical performance of LiMn0.9Co0.1O2 cathode materials for Li-ion batteries

Layer-structured LiMn0.9Co0.1O2 cathode materials for lithium-ion batteries were synthesized by ion exchange method. A layer of LiCoO2 was coated on the surface of the as-prepared LiMn0.9Co0.1O2 powder via melting impregnation method. The structure and morphology of the powders were characterized by means of x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties of the cathode materials were investigated using a half-cell in a potential range of 2.0–4.5 V versus Li/Li+. The LiMn0.9Co0.1O2 coated with 7 wt.% of LiCoO2 exhibited good electrochemical properties with a discharge capacity of 158 mAh g−1 and 89% charge retention after 50 cycles.

Photo-assisted chargeability of hydrogen storage alloy/(In0.9Cr0.1)NbO4?:?NiO electrode in KOH solution

Cr-doped InNbO4 powder was synthesized using a solid-state reaction and then loaded with 1.0 wt.% NiO on the particle surface. The powder was characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectrometry. The (In0.9Cr0.1)NbO4 : NiO showed a novel photocatalysis performance with obvious absorption in the visible light region. The Mm (Ni3.6Mn0.4Al0.3Co0.7)/(In0.9Cr0.1)NbO4 :NiO photoelectrode was then fabricated and its photo-assisted electrochemical behaviour was investigated. The electrode exhibited the obvious photo-assisted chargeable properties in KOH solution. The high photocatalysed activity may result from the increase in visible light absorption induced by Cr3 + doping and the higher degree of charge carrier separation induced by NiO particles loading on the Cr-InNbO4 particle surface.

Magnetron Sputtering Sn-Ag-O Thin Film Anodes For Rechargeable Lithium Ion Batteries

Sn-Ag-O thin films were deposited by DC magnetron co-sputtering in a gas mixture of Ar and O₂. The microstructure and morphology of the thin films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The Sn_2.3AgO_0.9 and Sn_1.3AgO_0.6 film films deposited at room temperature showed a mixture of crystalline and glassy structure in XRD patterns, whereas the Sn_0.1AgO_0.1 films only presented metallic silver diffraction peaks. Electrochemical performances of the thin film anodes were investigated by means of charge-discharge tests in half-cells. The volumetric specific capacity increased and the cycling stability decreased upon increasing the relative content of Sn in the films. For the Sn_2.3AgO_0.9 thin film, the cyclability was evidently enhanced after annealing at 200degC