The Preparation Of Iron-based Hydroxide Electrode Materials And Research Of Its Electrochemistry Property

Supercapacitors play an important role in the current energy storage field,and the main factor affecting their performance is the preparation of electrode materials.It has always been a difficult point in the research field to find electrode materials with high energy density and high cycle life.Under normal circumstances,transition metal oxides(hydroxides)have excellent Faraday capacitance performance and are the preferred electrode material for supercapacitors.However,due to their low conductivity and easy agglomeration and other shortcomings,they affect their performance in electrode materials.Performance.In this thesis,aiming at the shortcomings of current iron electrode materials,iron hydroxide/carbon material composite method is used to prepare high-performance anode materials.The main works are as follows:(1)Using melamine as a raw material,a massive carbon nitride is prepared by air calcination,and then subjected to oxygen etching at high temperature and ultrasonic peeling to obtain a nearly single layer of carbon nitride.Using ferric chloride hexahydrate and ammonium bicarbonate as raw materials,iron oxyhydroxide quantum dots are prepared by the co-precipitation method.The quantum dots are attached to the carbon nitride nanosheets in a self-assembled manner while being formed to obtain a sandwich structure iron oxyhydroxide/carbon nitride composite electrode material.Electrochemical tests show that at a current density of 1 A g^-1,its specific capacity can reach 270.8 F g^-1;after 3000 cycles of charging and discharging at a current density of 5 A g^-1,its capacitance performance can still be maintained as 78.3%.(2)Synthesize polyamic acid(PAA)by linear polycondensation method,then freeze-dry it into aerogel,and then undergo amidation treatment.After the amidation is completed,carbonization is performed to obtain a hard black aerogel.The nitrided aerogel is pulverized by high-speed ball milling,and a sheet-like nitrogen-containing carbon material is obtained.Then,the co-precipitation method is used to load the iron oxyhydroxide quantum dots on the nitrogen-containing carbon material,and finally the iron oxyhydroxide/nitrogen-containing carbon composite electrode material is obtained.Electrochemical tests show that at a current density of 1 A g^-1,its specific capacity can reach 230.1 F g^-1;after 2000 cycles of charging and discharging at a current density of 5 A g^-1,its capacitance performance can still be maintained as 81.5%.(3)The graphene oxide is prepared by the Hummers method,and then it is configured into a graphene oxide solution with a certain concentration.Then use the one-step hydrothermal method to hydrolyze FeCl₃·6H₂O in the graphene oxide solution at high temperature.At the same time,with the reduction of graphene oxide,?-FeOOH/rGO composite is formed.After the sample is washed and dried,it becomes reddish brown.The electrode material.Electrochemical tests show that at a current density of 1 A g^-1,its specific capacity can reach 299.3 F g^-1;after 2000 cycles of charging and discharging at a current density of 5 A g^-1,its capacitance performance can still be maintained as 81.5%.