Two different Co-based nanostructures were produced via thermolytic decomposition or reduction of proper cobalt precursors
in organic solvents under vigorous stirring. The effect of synthesis parameters on the shape, size, and composition of the
particles was examined. We present the differences in the structural and magnetic properties among the as-prepared sub-micron
Co ‘polypod-like’ particles, which display a remarkable value for saturation magnetization (182 emu/g), and the hollow CoO
nanoparticles, which exhibit weak ferromagnetic features. 相似文献
We report stress dependence of growth characteristics of epitaxial γ-Na0.7CoO2 films on various substrates deposited by pulsed laser deposition method. On the sapphire substrate, the γ-Na0.7CoO2 thin film exhibits spiral surface growth with multi-terraces and highly crystallized texture. For the γ-Na0.7CoO2 thin film grown on the (1 1 1) SrTiO3 substrate, the nano-islands of ∼30 nm diameter on the hexagonal grains are observed. These islands indicate that the growth mode changes from step-flow growth mode to Stranski-Krastanow (SK) growth mode. On the (1 1 1) MgO substrate, the large grains formed by excess adatoms covering an aperture between hexagonal grains are observed. These experimental demonstrations and controllability could provide opportunities of strain effects of NaxCoO2, physical properties of thin films, and growth dynamics of heterogeneous epitaxial thin films. 相似文献
Layered metal oxides have attracted increasing attention as cathode materials for sodium-ion batteries (SIBs). However, the application of such cathode materials is still hindered by their poor rate capability and cycling stability. Here, a facile self-templated strategy is developed to synthesize uniform P2-Na0.7CoO2 microspheres. Due to the unique microsphere structure, the contact area of the active material with electrolyte is minimized. As expected, the P2-Na0.7CoO2 microspheres exhibit enhanced electrochemical performance for sodium storage in terms of high reversible capacity (125 mAh g−1 at 5 mA g−1), superior rate capability and long cycle life (86 % capacity retention over 300 cycles). Importantly, the synthesis method can be easily extended to synthesize other layered metal oxide (P2-Na0.7MnO2 and O3-NaFeO2) microspheres. 相似文献
Ultrafast transverse thermoelectric voltage response has been observed in c‐axis inclined epitaxial La0.5Sr0.5CoO3thin films. Voltage signals with the rise time of 7 ns have been detected under the irradiation of pulse laser with duration of 28 ns. A concept, named response rate ratio, has been proposed to evaluate the intrinsic response rate, and this ratio in La0.5Sr0.5CoO3is smaller than that in other reported materials. The low resistivity is thought to be responsible for the ultrafast response, as low resistivity induces small optical penetration depth, and response time has a monotonous increasing relationship with this depth.
