Xunhui Xiong

Enhanced electrochemical properties of lithium-reactive V2O5 coated on the LiNi0.8Co0.1Mn0.1O2 cathode material for lithium ion batteries at 60 °C

The cycling performance of a lithium-reactive V2O5 coated LiNi0.8Co0.1Mn0.1O2 material at 60 °C is substantially improved by a wet-coating process. The V2O5-coated materials are obtained from drying a mixture consisting of NH4VO3 and LiNi0.8Co0.1Mn0.1O2 powders dispersed in ethanol at 85 °C followed by firing at 300 °C for 5 h. The morphology of the V2O5-coated LiNi0.8Co0.1Mn0.1O2 particle synthesized by this coating process is characterized by SEM, TEM and EDX analysis. The V2O5 layer is homogeneously coated onto the particle and the coating thickness was found to be approximately 10–30 nm. The capacity improvement at 60 °C is related to the fact that the highly distributed V2O5 near the surface diminishes the side reactions between the cathode and electrolyte. Moreover, the improvements may also benefit from the unique structure and properties of V2O5.

Consolidation of Cu based amorphous powder by hot pressing method

Abstract Amorphous Cu50Zr40Ti10 powder was fabricated in the particle size range <50 μm by gas atomisation method. Gas atomised Cu50Zr40Ti10 amorphous powder exhibits the glass transition temperature Tg of 629·5 K and the crystallisation temperature Tx of 693·2 K respectively. The gas atomised Cu50Zr40Ti10 amorphous powder possesses a high supercooled liquid region ΔTx of 63·7 K suitable for being hot pressed. In addition, the Cu50Zr40Ti10 amorphous powders were consolidated by hot pressing method based on an L9(34) orthogonal design. The optimum consolidation condition for the Cu50Zr40Ti10 amorphous powder is first precompacted under the pressure of 75 MPa, and then consolidated under the pressure of 450 MPa at the temperature of 380°C respectively. The significance of three factors is examined by the analysis of variance for the density and thermal conductivity respectively. The effect of three factors on the density and thermal conductivity is also discussed.