The Preparation Of Graphene Based Compound Hydrogel And Its Electrochemical Performance Study

As a kind of magic carbon materials, graphene possess excellent properties such as large surface area, high mechanical properties and electrical conductivity, which enable it to be potential materials for energy storage, semiconductor and biomedicine. However, restacking between the lamellae limits its industrial application. As an important derivative of graphene, Graphite Oxide (GO) can be reduced into graphene-based materials. Under a certain condition, GO can be formed into Graphene Hydrogel (GH) due to its gel properties. The unique spatial structure of GH can not only prevent the restacking of graphene sheets, but also is convenient as devices material.In this work, GH was prepared through a hydrothermal process from GO solution, which was prepared via a modified Hummers oxidation. Then GH was tested about its structure and performance. The results showed that GO was almost reduced into graphene with a three-dimensional structure and presented a good electrochemical performance.Based on these experiments above, Manganese carbonate/Graphene composite Hydrogel (MGH) and Cobalt tetroxide/Graphene composite Hydrogel (CGH) were prepared via a similar hydrothermal method. The effect of macrostructure, microstructure and the electrochemical performance of MGH and CGH induced by different feeding ratios, loading ratios, solvents and solvent amounts were considered. The result showed that MnC03and CO3O4nanoparticles could not only prevent the restacking of graphene layers, but also contribute to improve the specific capacitance of graphene-based composite materials. Comparing to MnO2(233.8F·g-1), MnCO3(13.5F·g-1) and GH (208.5F·g-1), MGH has a high specific capacitance of613.8F·g-1in a three-electrode system. Similarly, CGH has a relative high specific capacitance of247.9F·g-1comparing to CO3O4(77.9F·g-1) and GH (175.7F·g-1) in a two-electrode system.