Study On Preparation And Characterization Of Nanomaterial For Energy Storage

Based on detailed investigation of a great deal of related literatures, the preparation and the application of the nanomaterials for energy storage have been reviewed, and the recent development of carbon aerogel, nitrides, and oxides for supercapacitor and LiMn₂O₄ and SnO₂ for lithium battery were explained especially. Following that, doped MnO₂ was prepared by hydrothermal method, nanostructure was effectively controlled by the doping of vanadium and chromium, flower-like Ni(OH)₂ and NiO used for supercapacitor was synthesized, the composition ofγ-Mo₂N and several transition metals was successfully realized, and the supercapacitance of the as-prepared material was observably improved. By using peroxide and salt acetate, carbon aerogel with high capacitance was firstly obtained by the ambient pressure drying, and a fast and effective approach of the preparation of carbon aerogel with high capacitance was achieved. On the basis of hydrothermal method, LiMn₂O₄ and SnO₂ for anode material of lithium battery, ZnO and CuI were obtained. The research conclusions provide some original and innovative results, and the major contents can be summarized as follows:The nanoparticles of tetragonal a-MnO₂ were obtained from the reaction of potassium chlorate and sulphate manganese, and the morphology was changed intoβ-MnO₂ as the temperature up to 210℃. Vanadium and chromium ion was doped, orderingα-MnO₂ nanoparticles. Stick-sphere-like, fabricated orchid-like and symmetrical radial structure was obtained respectively by the doping of vanadium and chromium. The mechanism for the morphology was also discussed in the article. Owing to the interconnected net structure of the material, the manganese dioxide compound showed good supercapacitance, with the specific capacitance of 258 F/g after doping.Flower-likeβ-Ni(OH)₂ crystals were successfully prepared and a hydrothermal complexing-precipitation process was developed. The morphology of the flower-like was easily formed with excessive EDA. The composite of NiO and activated carbon demonstrated good electrochemical performance with 1 time broadened potential window and enhanced capacitance and power.Additive plays an important role on the morphology of SnO₂, for example: PVP and CTAB respectively result in the morphology of microsphere and the radial rods of SnO₂, sphericity changed into radial flower-like structure when Zn²⁺ was doped. Zn²⁺doped SnO₂ shows a high capacitance with its initial discharge-capacitance of 1614mAh/g. We got the function of composition of urea and PEG2000 in the synthesis of ZnO nanorods. Trigonometry cluster-like CuI was obtained by microemulsions, CuI nanorods was prepared by the method of precursor microemulsions, and cubic CuI was synthesized by hydrothermal method with the additive of SDS.LiMn₂O₄ was synthesized by hydrothermal method using MnO₂ as precursor firstly, with a uniformly distributed particle diameter and well formed crystal and high capacitance.The efficiency of the active electrode material was enhanced and the resistance and polarization of the electrode were reduced with the addition of carbon aerogel. VO₂ (B) doped LiMn₂O₄ as electrode nanomaterial showed a higher specific capacitance of 275mAh/g than pure LiMn₂O₄.The preparedγ-Mo₂N electrode showed good supercapacitance behaviors, with the potential window from -0.1 to 0.6V, and the capacitance of 126 F/g at a scan rate of 2mV/s. The potential window was broadened 0.20-0.35V after doping with chromium, tantalum, cobalt, vanadium and manganese. Manganese, tantalum and vanadium can enlarge the specific supercapacitance remarkably, and the maximum reached 316F/g.The important influence of category of catalysts to gel time and structure of product in the preparation of carbon aerogel was found, the catalysts arranged by the gradual value of specific capacitance of carbon aerogel are as follows: Na₂CO₃, NaHCO₃, Ca(OH)₂, HAc, NaAc. The treatment before activation plays an important role, after cryodrying treatment the specific capacitance can reach 1.4 times, while it can reach 2.4 times after carefully grinding. Additive of peroxide and amino acid can remarkably improve specific capacitance, with the maximum times of 1.6. The enhancement of middle pore distribution near 2nm plays a crucial role in the increase of specific capacitance. The catalysis of HAc and its salt not only improve the value of specific capacitance to 270F/g, but also leave out supercritical drying and treatment of the solvent exchange, shorten gel time radically, then realize a fast and effective approach of the preparation of carbon aerogel.