Study On The Preparation Of FeCo₂X₄?X=O,S?/Polypyrrole Hybrid And Its Supercapacitance

The electrochemical properties of supercapacitor electrode materials have a great relationship with their composition,structure,morphology,therefore,designing electrode materials with appropriate composition and stable morphology structure is an important approach to improve the performance of supercapacitors.In this paper,different binder-free electrode materials were prepared via a simple hydrothermal method,and/or in-situ polymerization by using morphology structure control and reasonable design of different components,and the electrochemical properties as binder-free supercapacitors were investigated systematically.Main works are as follows:?1?Through the hydrothermal method directly growth on nickel foam iron,cobalt precursors,and then by calcining turn iron cobalt precursors to iron cobalt oxides,and the success of the preparation of growth on nickel foam FeCo₂O₄ nanometer array,the material directly as a supercapacitor electrode materials testing of their properties,obtain the higher specific capacity:in the current density of 1 mA cm^-2,its specific capacity reached 1190.47 mF cm^-2,when the current density increased to50 mA cm^-2,its specific capacity still maintain the original 61.09%.At the same time,the electrode material also shows good electrochemical cycle stability.Under the current density of 30 mA cm^-22 cycling for 2000times,its specific capacity without attenuation.These results indicate that the composition of electrode material is a prospect of supercapacitor electrode materials.?2?In order to further enhance FeCo₂O₄ electrode materials specific capacity,we have designed FeCo₂O₄-inorganic organic hybrid polypyrrole electrode materials.With long FeCo₂O₄ nickel foam as base,again with low temperature oxidation polymerization in situ growth outside a layer of conductive polymer polypyrrole,on the preparation of electrode materials,its specific capacity reached 1932.73 mF cm^-2,compared with pure inorganic electrode material,its performance has improved obviously.?3?Of the existing research literature suggests that the metal sulfide is superior to the electrochemical performance of metal oxide,and the current research on binary metallic sulfide mainly concentrated in Ni-Co,few literature reported the composition of binary metallic sulfide Fe-Co.So design through the hydrothermal sulfide method,to convert iron cobalt precursors to iron cobalt sulfides,the oxygen into elemental sulfur in FeCo₂O₄,synthesized growth on nickel foam FeCo₂S₄ nanometer array.Oxides and sulfides in comparison with its specific capacity is greatly improved,and the performance of binary transition metal sulfides are better than single transition metal sulfide.At a current density of 10 mA cm^-2,FeCo₂S₄ nanometer array's specific capacity reached 7155.93 mF cm^-2.When the current density increased to 50 mA cm^-2,its specific capacity still remain to 1644.07 mF cm^-2.At the same time,the electrode material also showed excellent electrochemical cycle stability.the capacitance retention is¹00%after 10000 cycles at a high current density of 50 mA cm^-2.These results suggest that FeCo₂S₄ electrode material has high research value in the application of supercapacitor.?4?Although FeCo₂S₄ electrode materials has high specific capacity and good cycle stability,but its rate performance has much room to improve,so we designed the FeCo₂S₄-PPy inorganic/organic hybrid electrode materials.To loading the FeCo₂S₄ on nickel foam as the basement,and then grow a layer of conductive polymer-polypyrrole?PPy?in the low temperature in situ oxidation polymerization.FeCo₂S₄-PPy electrode materials for preparation of nanowire arrays,ratio of material performance increase to 42.66%.