Synthesis Of Ferrite-Based Nanocomposites And Their Applications In Supercapacitors

Supercapacitor,also known as electrochemical capacitor?EC?,is a new type of energy storage device.On the one hand,its energy density is much lower than the battery;On the other hand,its shelf life and service life is much longer than the battery.The development and research of Super capacitor is mainly to replace the pulse battery,which is mainly because the power,shelf life and cycle life of battery is relatively short,and can not meet today's increasingly demanding application.The electrode material of the capacitor largely determines the performance of capacitor,so the research on the electrode material of supercapacitor has become the hotspot of material science recently.At present,there are three main types of electrode materials: carbon material,metal oxides and conductive polymers.The following works were carried out in this theme:1)Mn-doped Fe₃O₄ nanocomposites had been synthesized by hydrothermal method using FeCl₃.6H₂O as the sole source of iron,sodium acetate as precipitant and ethylene glycol as reducing agent and solvent.The structures were characterized by transmission electron microscopy?TEM?,scanning electron microscopy?SEM?and XRD.The nucleation and growth mechanism of Fe₃O₄ nanospheres were studied by controlling the reaction time.The electrochemical performance of Mn-doped Fe₃O₄ nanocomposites were investigated by using KOH as electrolyte.The results show that,due to moderate initial nanocrystal density and microsphere size,the Fe₃O₄-Mn-1.5 has better electrochemical performance: excellent specific capacitance,outstanding cyclic stability.2)Polyaniline and its derivatives,as important conductive polymers,have a wide range of applications,such as coating,battery,sensor,and so on.Iron oxide @ Poly-ophenylenediamine composite has been synthesized by using FeCl₃.6H₂O as the sole source of iron and oxidizing agent,ammonia as precipitant,deionized water as solvent.The structure and composition of the product were characterized by scanning electron microscopy,projection electron microscopy,infrared spectroscopy,X-ray powder diffraction,N₂ adsorption desorption and thermogravimetric analysis.The electrochemical performance of POPD-Fe nanocomposites were investigated by using KOH as electrolyte.The results show that,the POPD-Fe-8 has better electrochemical performance: excellent specific capacitance,outstanding cyclic stability.3)In addition,on the basis of the previous experiment,MnCl₂ was added to prepare the conductive polymer with bimetallic oxide.In the paper,the effect of FeCl₃.6H₂O concentration on the morphology and size of the product was also been investigated.The results show that,the POPD-Mn-Fe-4 has better electrochemical performance: excellent specific capacitance,outstanding cyclic stability.