Synthesis Of Self-supporting Cobalt-based Bimetal Oxide/Sulphide Materials And Their Performance As Electrode Materials For Supercapacitors

Supercapacitor is a new type energy storage device with performance between lithium-ion battery and conventional capacitor.Compared with lithium-ion batteries and conventional capacitors,supercapacitors have the superiority of high power density,fast charge and discharge speed,environmental friendliness,long service life,etc.,they have potential applications in the fields of electric vehicles and portable electronic devices.Therefore,supercapacitors are one of the research focus for energy storage devices in rencent years.In this thesis,we mainly researched the preparation of in-situ cobalt-based bimetal oxide/sulfide nanomaterials grown on nickel foam/carbon cloth and its application in supercapacitors.The main research contents and details are as follows:?1?The self-supporting NiCo-precursor material was grown in situ on the carbon cloth by electrodeposition method which of Co?NO₃?₂·6H₂O and Ni?NO₃?₂·6H₂O were used as cobalt source and nickel source,respectively.And then the NiCo-precursor materials were Annealed in the air to obtained the honeycombed NiCoO₂/CC nanomaterials.The NiCoO₂/CC material was directly used as a supercapacitor electrode material and it exhibits excellent electrochemical performance,showing a high capacitance of 1874 F/g at the current density of 1 A/g,even the current density increased to 30 A/g,the capacitance is still maintained to1726.4 F/g.After 5000 charge/discharge cycles,its capacitance didn't has clear decay,showing excellent rate and cycle performance.NiCoO₂/CC material was used as positive electrode material,activated carbon?AC?was used as negative electrode material,and 6 M KOH solution was used as an electrolyte to assemble asymmetric supercapacitor?NiCoO₂/CC//AC/CC?.Thecapacitanceof asymmetric supercapacitor is as high as 144.23 F/g,and when the current density is increased to 8 A/g,the capacitance of the supercapacitor is still 82.71 F/g,and the maximum energy density is 51.28 Wh/kg,indicating NiCoO₂/CC material has great application potential as supercapacitor electrode material.?2?Co-Mo-precursor nanomaterials were synthesized in situ on a nickel foam by hydrothermal method which using Co?NO₃?₂·6H₂O and Na₂MoO₄·2H₂O as cobalt and molybdenum sources,respectively.Then,self-supporting CoMoS₄/NF materials was obtained by hydrothermal method using TAA as sulfur soources to sulfurated CoMoO₄/NF?Nickel Foam?,and the mass loading of the CoMoS₄material is about2.29 mg/cm².The obtained CoMoS₄/NF nanomaterial was used as a supercapacitor electrode material and its electrochemical performance was tested.The capacitance was as high as 5665 mF/cm²?2473.79 F/g?at current density of 5 mA/cm².When the current density is increased to 30 mA/cm2,the capacitance is still maintained to 4218mF/cm²?1841.92 F/g?,and after 8000 charge/discharge cycles at a current density of30 mA/cm²,it maintained 65.32%of the initial capacitance,indicating that CoMoS₄/NF nanomaterials have excellent rate performance and great cycle stability.