Preparation And Research Of Electrical Properties Of Fe₂O₃-Based Mesoporous Materials

With the development of the times,the application of lithium ion batteries were more and more extensive.Lithium ion batteries have high electrochemical properties,it did not cause pollution and no memory effect when used.So,it was widely used in many electronic devices and new energy powered vehicles.Researchers persevere in optimizing lithium-ion materials to meet people's needs for high-performance lithium-ion batteries.Fe₂O₃ has high theoretical specific capacity,however,Fe₂O₃ face serious volume change in charge and discharge which cause serious capacity loss,and the conductivity of Fe₂O₃ is poor.The high reactivity,favourable charge transport properties and novel structural merits of nanomaterials can effectively improve the performance of lithium ion batteries.In this paper,the preparation and electrical properties of hollow spherical mesoporous Fe₂O₃,double-shell Ti O₂ hollow spheres and Fe₂O₃@Ti O₂ double-layer hollow spheres were studied.The specific work is as follows:(1)The subunits controlled?-Fe₂O₃ hollow spherical particles were synthesized with a facile hydrothermal method.The two-dimensional single-crystalline nanosheets associated with the one-dimensional single-crystalline nanorods self-assembled into the three-dimensional hierarchical flower-like mesoporous?-Fe₂O₃ hollow spheres by adjusting the relative amount of cetyltriethylammnonium bromide in the reac-tion system.The electrochemical measurements indicated that the three-dimensional hierarchical flower-like?-Fe₂O₃ hollow spherical particles contained a remarkable specific capacity,a lower irre-versible capacity loss and an excellent rat performance for their higher specific surface and mesoporous structure.The discharge capacity of the electrodes made by the three-dimensional hierarchical flower-like a-Fe₂O₃ hollow spheres was retained at 875 m A g^-1 even after 100 charge-discharge cycles at the current densities of 200 m A g^-1.(2)Firstly,by using carbonaceous microspheres as templates to adsorb Ti Cl₄aqueous solution,by controlling the adsorption time and calcination to remove the carbon sphere template,the product is double-layer Ti O₂ hollow sphere.By adjusting the adsorption time of carbon spheres in Ti Cl₄ aqueous solution,adsorption in Fe Cl₃ aqueous solution after drying,controlling the adsorption time and calcining,the product is Fe₂O₃@Ti O₂double-layer hollow sphere.The electrochemical measurements indicated that the Fe₂O₃@Ti O₂ double-layer hollow spheres have high specific capacity and better reversible properties.The discharge capacity of the electrodes made by the Fe₂O₃@Ti O₂ double-layer hollow spheres was retained at 735 m A g^-1 even after 100 charge-discharge cycles at the current densities of 200 mAg^-1.