Metal Oxides Of Different Morphologies Hydrothermal Synthesis And Electrochemical Properties

In this paper, a series of studies have been exhibited with respect to the hydrothermal synthesis and electrochemical performance of metal oxides with different morphologies, which is composed of three parts. The first part focuses on the synthesis of Co3O4/graphene composite and Fe2O3/graphite composite by a direct hydrothermal method based on the poor rate capability. of metal oxides as the anode materials for lithium-ion batteries. Moreover, the important role of carbonaceous materials in improving the specific capacity and cyclic stability has also been disussed briefly. The second part focuses on the preparation of SnO2/graphite composite and SnO2nanorod arrays on Ni foam via in situ growth through hydrothermal technique due to poor electrical conductivity and serious volume effect of SnO2as the anode materials for lithium-ion batteries, in which graphite and Ni foam are used as the substrates. In addition, we also make summaries of improving SnO2lithium storage with the help of various analytical methods. The last part focuses on the modification of metal oxides to overcome the defects of poor electrical conductivity and serious volume effect when used as the anode materials for lithium-ion batteries. Polystyrene (PS) micro spheres are adopted as the hard template to synthesize hollow carbon spheres, morphology controlled Fe2O3, NiO and ZnO particles through a hydrothermal process. Besides, the influence of structure on the charge/discharge properties has been summarized. The concrete content of this paper is described as follows:Preparation of Co3O4/graphene composite and Fe2O3/graphite composite are realized through a direct hydrothermal treatment. The two composites show much better electrochemical performance than the MxOy used in each system. Co3O4/graphene composite delivers an initial discharge capacity of1452.8mAh-g-1and charge capacity of831.7mAh-g-1at a current density of50mA/g. After100cycles, it exhibits slightly capacity decay with a loss of174.8mAh-g-1.Synthesis of SnO2/graphite composite and SnO2nanorod arrays on Ni foam via in situ growth through hydrothermal technique has been successfully realized. Morphological characterization reveals that SnO2nanorods grow densely and vertically on the substrates. The results demonstrate that the introduction of substrates can effectively prevent agglomeration of particles and improve the electrochemical performance of electrodes. At a current density of0.8A/g, SnO2nanorod arrays on Ni foam shows superior electrochemical properties, which maintains521.0mAh·g-1over30cycles.Hollow carbon spheres, morphology controlled Fe2O3, NiO and ZnO particles were synthesized by using PS microspheres as the hard template to through a hydrothermal process. The test results discover that the obtained materials have enhanced rate performance. It can be cleraly observed hollow carbon microspheres exhibits a reversible specific capacity of1189.3mAh·g-1at a current density of0.4A/g with a high capacity retention of70%after100cycles.Through the above research, different morphologies controlled synthesis of metal oxides/carbonaceous materials composites and metal oxides have been studied through three ways based on the hydrothermal method. We found that the as-prepared electrode materials have not only solved the problem of the carbonaceous materials with low specific capacity, but also effectively overcome the defects of metal oxides during lithium-ion intercalate/deintercalate process. The work that we have been studied can benefit to the further research.