| Lightweight and flexibility is one of the most important development trend of portable electronics, and energy storage device is the core-block of the portable electronic products. Therefore, whether flexible portable electronics become popular depends on improving the technology, especially by developing the flexible high-performance energy storage devices. Supercapacitors are a new type of energy storage device between static capacitor and secondary batteries, the promising application of supercapacitors in the fields such as mobile telecommunication, information technology, consumer electronics, electric vehicle, aviation, and military force, have been attracting more and more attention throughout the world. Previous studies have shown that excellent performance of SCs and LIBs have been mainly decided by the type and nanostructure of the electrode material. Therefore, study on supercapacitor and lithium-ion battery anode materials and other basic research areas of great theoretical and practical significance. In this thesis, the transition metal oxide nanostructure materials and their composites as the core, several different properties and different morphologies of nanomaterials by a simple hydrothermal method on different flexible conductive substrates were prepared, and its formation mechanism, structure, morphology, physical and chemical properties, especially the electrochemical properties of a comprehensive in-depth research, mainly includes the following aspects:1. Preparation and electrochemical energy storage research on single-phase nickel-based metal oxide nanomaterials(a) Through a simple, two-step method without template-assisted:large area two-dimensional nanosheets array of NiO was grown on a soft Ni mesh substrate by a simple hydrothermal approach combined with a post-annealing treatment. The characterization of XRD, SEM, TEM, Raman and BET respectively for NiO nanosheets crystal structure, particle morphology and surface area analysis. Final, the NiO nanosheets array was directly used to as a supercapacitor electrode material. Cyclic voltammetry (CV), constant current charge-discharge and electro-chemical impedance (EIS) performance test results show that the as prepared electrode material with good rate capability and excellent cycle performance, due to its reasonable design of nanometer structure.2M KOH aqueous solution as electrolyte, obtained a high capacitance is850 F/g at the current density of5A/g, after3000cycles at the same current densities the capacity remains at91.1%. To sum up the NiO nano array material has high quantity of unit capacitors, excellent cycle stability and great application prospect.2. Preparation and electrochemical energy storage research on composite phase nickel cobalt oxide metal oxide nanomaterials(a) Thought a simple hydrothermal approach combined with a post-annealing treatment, large area of one-dimensional porous NiCo2O4nanoneedle array was grown on flexible carbon cloth substrate. When it was directly used as a anode material for supercapacitor, in2M KOH aqueous solution as electrolyte, the current density of2A g-1to obtain a high capacitance is660F/g, after3000cycles at the same current densities the capacity remains at91.8%. At different magnifications of current density, anode material showes excellent charge-discharge cycle performance, indicate that the material has good electrochemical stability. This is mainly due to the NiCo2O4material itself has a highly reversible electrochemical properties and rational design with one-dimensional arrays.(b) We furthermore develop a facile modified method to fabricate porous N1CO2O4nanoneedle arrays with robust mechanical adhesion on flexible Ni form, nanoflake array and sisal-like MCO2O4nano spheres in the absence of substrate. When used as anode electrodes for supercapacitor, found that one-dimensional NiCo2O4nanoneedle has the best electrochemical performance, mainly own to its one-dimensional needle rapid and orderly electron transport in electrolyte and sufficient electrolyte flow. |
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