Preparation And Study On Supercapacitor Performance Of CNT@CoS_x/NiCo-LDH Nanocomposites

With the transitional consumption of fossil energy,it is significant for us to develop nano-electrode materials with excellent electrochemical properties to realize high-efficiency energy conversion and storage.However,under high rate multiple cycles,it is limited because of its poor conductivity and structural instability.Metal-organic framework compounds(MOF)have the advantages of variety diversity,tunable pores,and high specific surface area.Combining sulfide and hydroxide derived from MOF materials improves the stability of the material structure well.Therefore,the combining materials become a topic which is highly focused on high-performance electrochemical energy storage electrode materials.In this work,CNT@ZIF67,CNT@Co S_xand CNT@Co S_x/Ni Co-LDH composites were prepared on good conductivity carbon nanotubes using a structurally stable zeolitic imidazolate cobalt-based organic framework(ZIF-67)as the precursor and template to achieve a controllable synthesis of material composition and structure.To realize the controllable synthesis of the structure and composition of the composite,and to make the best of the synergistic complementary effect of the three compounds,the electrochemical performance of the composite as electrode material for supercapacitors is gradually improved.(1)Mixed the CNT with the ZIF67 of different proportions by simple mechanical stirring,synthesized CNT@ZIF67 nanocomposites.We investigated the effects of the mass ratio of CNT and ZIF67 on the morphology and electrochemical properties of CNT@ZIF67 composites.The results showed that when the m(CNT):m(ZIF67)was 1:2,CNT@ZIF67's specific electric capacity reached 782.7 F g^-1at 1 A g^-1in the three-electrode system.(2)Vulcanized the CNT@ZIF67 by water bath reflux method,CNT@Co S_xnanocomposites were obtained.We investigated the effects of curing agent dosage and healing time on the morphology and electrochemical properties of CNT@Co S_xnanocomposites.The results show that When the dosage of a vulcanizing agent was24 mg and healing time was 1.5 h,CNT@Co S_x's specific capacitance reached 2107.0F g^-1at 1 A g^-1in the three-electrode system.The specific capacity of the CNT@Co S_xmaterias greatly il improved,and the cycling performance and energy density are significantly improved compared with the CNT@ZIF67 material.(3)The nickel source of CNT@Co S_xnanocomposites was added by mechanical stirring at room temperature,CNT@Co S_x/Ni Co-LDH nanocomposites were obtained.We investigated the effects of nickel content on the morphology and electrochemical properties of CNT@Co S_x/Ni Co-LDH nanocomposites.The results showed that when the nickel source was 100 mg,CNT@Co S_x/Ni Co-LDH's specific capacitance reached2794.6 F g^-1at 1 A g^-1three-electrode system.The CNT@Co S_x/Ni Co-LDH material's specific capacity is greatly improved,and the cycling performance and energy density are significantly improved compared with the CNT@Co S_xmaterial.There are 75 pictures,5 tables,and 104 references in this paper.