Research On Preparation And Application Of Magnetic Iron Oxide Based Nanocomposites

Magnetic iron oxide nanomaterials have been widely used in lithium-sulfur batteries,supercapacitors,and anti-electromagnetic interference fields.However,iron oxide nanoparticles have a trend to agglomerate.In order to overcome the shortcomings of a single nanometer iron oxide material,this dissertation uses a one-step low temperature chemical deposition method to composite?-Fe₂O₃ with silica and multi-layer graphene respectively.The application of composite materials in anti-interference magnetic rings and electrode materials of lithium-sulfur batteries was discussed.The main research contents are as follows:?1?An iron oxide nanoparticle/silica composite material is prepared by a one-step low temperature chemical deposition method,and an anti-electromagnetic interference magnetic ring is made.The effects of the amount of ethyl orthosilicate on the microstructure and magnetic properties of composites were studied.The research results show that iron oxide and nano-silica nanoparticles are obtained by this method,in which nanocrystalline iron oxide and amorphou silicon are uniformly distributed.As the amount of orthosilicate acetate increases,the proportion of silica in the composite material increases,and the magnetic properties decrease.The composite material has a very small impedance at low frequencies below 5MHz and a large impedance at the frequency range of 300MHz to 2GHz,indicating the possible application on a high-frequency anti-electromagnetic interference magnetic ring.Meanwhile,nano-silica powder is added to reaction solution to prepare iron oxide/silica core-shell composite,and the results show that the obtained composites also have good resistance properties.?2?Nano-iron oxide/multilayer graphene composites were prepared by a one-step low temperature chemical deposition method,and the composites were used to load sulfur The performance of the composites as cathode materials for lithium-sulfur batteries was studied.The influence of sulfur injection temperature on the electrochemical performance of composites was studied.The research results show that the cathode material treated under the reaction conditions at 140?shows the best electrochemical performance,and the composite material has good rate performance and cycle stability,showing the material has a good application prospect as a sulfur carrier in lithium-sulfur batteries.Meanwhile,the anti-electromagnetic interference magnetic properties of iron oxide/multilayer graphene composites were also researched.Due to the synergistic effect of iron oxide nanoparticles and multilayer graphene,the composite shows good impedance characteristics at high frequency range.