Synthesis And Lithium Storage Properties Of Molybdenum Oxide/C Nanocomposites

Molybdenum dioxide （MoO₂） is a very unique transition metal oxide with distortedrutile structure. It has the advantages of high conductivity, high melting point, hightheoretical specific capacity and high chemical stability, which makes it a candidate for theanode material of lithium-ion battery. However, its low practical capacity and poor cyclestability limit its practical applications. The main contents of this dissertation are toimprove the capacity and cyclability of the anode material of MoO₂/C nanocomposites toimprove their cyclibility; on the basis of the optimized MoO₂/C nanocomposites, theMoO₂/WO_x/C composite with enhanced electrochemical properties was prepared. Anefficient method, microwave solid-phase sintering, was developed to synthesize theMoO3/Super P composite. The dependence of the electrochemical performance on thepreparation conditions was systematically investigated.MoO₂/C anode materials were synthesized through a conventional solid phasemethod. Glucose was introduced as the carbon source. The effects of different carboncontent and sintering temperature on the crystallinity and morphology and the influence ofdifferent conditions on electrochemical properties were studied. Experiment results showthat the size of MoO₂particales prepared at500°C decreases gradually with the increaseof the carbon content. It is found that the MoO₂product with a carbon content of10%hasthe best cycling performance. The first discharge specific capacity is as high as1190mAhg^-1at a current density of50mA g1. After100cycles, the discharge capacity remains706mAh g^-1, which is almost twice of the theoretical capacity of graphite (372mAh g^-1).On the basis of the optimized MoO₂/C, the MoO₂/WO_x/C composites was prepared.The influence of different molar ratios of MoO₂to WO_x,on the electrochemicalperformance and rate capability of MoO₂/WO_xcomposite was systematically explored.We synthesized MoO3/C by a microwave solid-phase sintering method with Super Pserving as the carbon source. This rapid route could reduce the reaction time, improveefficiency, decrease particle size, and enhance the electrochemical properties of thematerial. The carbon content, crystallinity, micro-structure, morphological characterization were investigated by TG-DTA, XRD, and SEM. The electrochemical properties wereinvestigated by galvanosatic charge-discharge to assess the specific capacity and cyclingperformance.