Preparation And Electrochemical Performance Study Of Graphene-based Metal Oxide Nanocomposites

With the development of the technology, nanomaterials with single property cannot meet the demand at the moment. Apart from surface effect, volume effect and quantum size effect of nanomaterials, nanocomposites also possess synergistic effect. Comprehensive synergistic effect of the various components can improve the surface properties and the contact area of the various components, leading to better electrochemical performance.Graphene and its derivatives have broad prospects for application due to their flexibility, high conductivity, excellent thermal stability and huge surface area. The combination of graphene and its derivatives with other functional nanomaterials is an effective way to meet increasing demand. Graphene-based nanocomposites have been applied in catalysis, sensors, energy storage, and many other fields. It is important to obtain graphene-based nanocomposites in a simple and controllable way. The most common used methods are in situ crystallization, electro-deposition, solution method, which are often involved with complicated process. In this work, we use electrospinning to fabricate graphene embedded nanofibers and solution evaporation to prepare graphene oxide wrapped nanocomposites, and measure the electrochemical properties of graphene-based nanocomposites.1) The SnO2@G nanofibers were fabricated by electrospinning along with heat treatment. And we used solvent evaporation to wrap the obtained SnO2@G nanofibers with graphene oxide, forming SnO2@G-GO nanocomposites. The morphology and microstructure of the samples were characterized by XRD, TEM, SEM, BET and Raman. The test results show that a multilayer structure SnO2@G-GO nanocomposites were obtained. As the experiments results shows that SnO2@G-GO nanocomposites has a special electrochemical response to water and can serve as humidity sensing material. The water can be detected by the SnO2@G-GO based sensor quickly and accurately.2) The CoMoO4 nanofibers and lotus-root like CoMoO4@G nanofibers are obtained by eletrospinning along with heat treatment. Morphology and microstructure were characterized by XRD, TEM, SEM and so on. We use testing system to study the lithium-ion storage performance of the samples. The results show that the addition of graphene greatly enhances lithium-ion storage performance of CoMoO4. Compared with the pure CoMoO4 NFs, the prepared lotus root-like CoMoO4@G NFs electrode displays higher reversible capacity of 735 mAh g-1 at 100 mA g-1, better rate capability and cycling stability (capacity retains 80% based on the second cycle even after 200 cycles,)...