Metal Oxide / Graphene (carbon Nanotube) Matrix Composites Controlled Preparation And Electrochemical Energy Storage Properties

Carbon materials have received much attention due to their high specific surface area, good electronic conductivity, and chemical stability recently. However, their practical applications as advanced energy-storage devices have been limited owing to their relatively low specific capacitances. On the other hand, transition metal oxides possess high theatrical specific capacitances and tailoring structures features, but, their cycling stability is not good. As a result, performing the study on the controlled synthesis and electrochemical investigation of the carbon/metal oxide composites would become one of interesting research topics presently. This work main involves in the synthesis of FeMnO3hollow sphere, nanostructural Co3O4particles, as well as their combination with graphene and/or carbon nanotube to prepare carbon based functional composites. The prepared carbon based composites as supercapacitor and lithium ion battery display high specific capacitances, good conductivity, and excellent cycling durability via utilizing their synergetic effects. The detailed results were seen the following:1. FeMnO3hollow sphere are fabricated using simple aging reaction and thermal-treatment process. The as-prepared FeMnO3hollow sphere and graphite oxide are composite via hydrothermal reaction. The as-prepared samples are well-characterized utilizing X-ray powder diffraction (XRD), Scan electron microscope (SEM), Transmission electron microscope (TEM), X-ray photoelectron spectrum (XPS), and Raman spectra techniques. The results demonstrate that the prepared FeMnO3samples undergo specific morphology transition from hollow spheres to solid rod-like aggregates, as accompanied by enhanced crystallization with increasing calcination temperature. Moreover, the prepared FeMnO3/RGO composites are employed as the electrode for supercapacitor. Electrochemical measurement results indicate that the FeMnO3/RGO electrode displays a significantly enhanced specific capacitance of189F g-1and improved cycling lifetime. The likely cause is the synergetic effects between the hollow spherical structure and the high conductivity of RGO. More importantly, the presented synthetic approach is facile, controllable, and reproducible, which could represent a promising avenue for preparing other ferrite-based composites with tailored morphologies and surface textures.2. Co3O4/multiple wall carbon nanotube (MWCNT) hybrid materials were synthesized via strong ultra-sonication assisted shake and magnetic stirring treatment processes. the as-obtained Co3O4/MWCNT hybrids were employed as anode electrolyte materials, their maximum discharge capacity can delivered to1250mA h g-1at current density of0.2C. The capacity of the electrode can be retained above81%after proceeding70cycles for loading20wt%MWCNT sample2, which could be associated with specific hybrid structure as well as the addition of MWCNT. More importantly, the present synthetic approach is facile, controllable, and scalable, which was easily facilitated to prepare of other hybrid materials with specific textures.3. FeMnO3hollow sphere/multiple wall carbon nanotube (MWCNT) composite materials were synthesized via strong ultra-sonication assisted shake and magnetic stirring treatment processes. The as-obtained MWCNT/FeMnO3composite materials used for supercapacitor electrode materials and electrochemical measurement results show that the presented MWCNT/FeMnO3electrode specific capacitance (132F/g) for loading0.02g MWCNT. This paper adopted synthesis method may be applied to other similar metal oxide and MWCNT composite materials.