Study On Nanosized Spinel Lithium Manganate Prepared By An Integrated Technique Of High-gravity Technology And Microwave Technology

One of the most studied materials in this field is spinel LiMnO4, which is considered as very promising lithium battery cathode material due to its high coulombic efficiency, fast charging-discharging reactions, low cost, and no toxicity。Among of these methods, the solid-state reaction is the simplest method to obtain spinel LiMn2O4 However, it has several disadvantages; it results in inhomogeneity, irregular morphology, a large particle size, a broad particle size distribution, poor control of stoichiometry, and longer periods of sintering followed by several grinding process. Hydrothermal process enables the synthesis of the material at a far lower temperature than that of the conventional sintering method, it is difficult to control the composition of the materials precisely. Sol-gel precitation can produce highly homogeneous nanometer sized particles with a narrow particle size distribution has been developed. But the sol-gel method has a complex synthesis route and high synthetic cost. Spray pyrolysis is a new synthetic method of inorganic materials in recent years, which can solve the disadvantages of the traditional liquid phase method and solid phase method. However, spray pyrolysis method is easy to form the hollow particles, the particles’broken pieces will produce debris. This is the not hope to be in the process of preparation. Compared with these methods, co-precipitation is one of the most application prospects because of the cheap raw materials, a simple synthesis and easiness to carrying out. However, the particle size distribution and the dispersed is not well.In this present work, we have synthesized nanosized spinel LiMn2O4 by an integrated technique of high-gravity technology and microwave technology. The method combines high-gravity field and microwave field for the first time. And it has combined Helix Channels of high gravity rotating bed reactor which can control grain size and low-cost advantages and the advantage of microwave controlled calcined. In this paper, we first studied the influence of different process conditions on the preparation of spinel LiMn2O4 by means of TG-DSC, XRD, SEM, TEM and other methods to analyze product. The results show that nanosized spinel LiMn2O4 powders with high crystallinity, uniform particle size, and the average size of about 60 nm can be synthesized when the speed of RHBC is 1000pm, ammonium carbonate as precipitant,microwave calcinations at 750℃ for 2h.And then the paper studied the Ce element doping effects on spinel LiMn2O4. Investigated the influence of different doping amount on the product performance, the products were characterized by means of XRD, SEM. The results show that the Ce element doping does not affect the spinel crystal structure, and doped Ce products have higher crystallinity and crystal properties after better. Before and after doping spinel particles are small particle size, uniform distribution and good dispersion. But it does not affect the morphology of products.