Synthesis And Properties Of V₂O₅ And V₂O₅ Composite Materials

Advanced rechargeable lithium ion batteries are attractive for use in consumer electronic and electric vehicle (EV) application because of a favorable combination of voltage, energy density, cycling performance, self-discharge ratio and environmental protection. Intensive research is being conducted to further improve the performance of lithium ion batteries and reduce the cost of electrode materials. On the base of reviewing the development of lithium ion battery and its cathode materials in detail, vanadium pentoxide (V₂O₅) was chosen as cathode material and their synthesis and modification were studied.In this paper, the preparing technological parameters, formation mechanism and structures of V₂O₅ xerogel (V₂O₅XRG), V₂O₅ aerogel-like (V₂O₅ARG-like) and V₂O₅/acetylene black(AB)/Nd₂O₃ composite are systematically studied and discussed, and some properties of the four types of V₂O₅ electrode materials are measured as cathode materials for lithium ion batteries. The main results are as follows:Amorphous V₂O₅ (a-V₂O₅) was prepared from crystalline V₂O₅ (c-V₂O₅) by ultrasonic wave-melt quenching method. Based on the experimental results, the effects of ultrasonic wave in this work have been proved and the problems existing in this work and the corresponding improvements have been pointed out. Then the influence of ultrasonic wave, reaction strength and time on the quality of products has also been studied. Experimental results manifest that ultrasonic wave has the advantage of restraining the formation of greater grains and keep higher specific surface area of the ultrafine powder in the preparation of the a-V₂O₅ powder.The influences of the calcination temperature and time, the concentration ratio of deionized distilled water to c-V₂O₅ and the agitation time on the synthesis of a-V₂O₅ were studied by orthogonal array design and the interactions between the parameters were considered. So the optimum experimental factors were obtained. Lithium rechargeable battery positive electrodes based on these optimum conditions could lead to experimental cells with large discharge specific capacity and good cycling performance.