Preparation And Electrochemical Performance Of Nickel-aluminum Layered Double Hydroxide Composite Materials

Layered double hydroxides?LDHs?are considered as one of the most potential supercapacitor materials because of their unique two-dimensional nanostructure,high electrochemical activity and high theoretical specific capacitance in alkaline electrolyte.However,LDHs have their inherent drawbacks,for instance the poor electronic conductivity,poor cycling stability and easy agglomeration,which limit their application in supercapacitors.To overcome these defects,LDHs is usually compounded with carbon conductive materials to improve the electrical conductivity and mechanical strength of the composites,thus greatly improving the electrochemical properties of the composite material.Ni-Al LDH/rGO composites with ultra-thin structure were prepared by exfoliation and self-assembly techniques.A series of electrochemical performance tests were performed.The results show that the current density of exfoliated Ni-Al LDH/rGO increases from 1 A g^-1 to 20 A g^-1,and the capacity retention rate is 74.9%.The specific capacitance of the composite material remains as 86.5%after 2000 cycles.The assembly of Ni-Al LDH/rGO//AC asymmetric supercapacitor device further demonstrates that the Ni-Al LDH/rGO material has excellent power density and energy density.The Ni-Al LDH/CNTs composites with a core-shell structure were prepared by a hydrothermal reaction method.The results show that NALC-8 exhibits excellent electrochemical performance,which has a high specific discharge capacity of 991 F g^-1at 1A g^-1.The capacity retention rate of NALC-8 was 78.2%after 2000 cycles,which was significantly higher than that of pure NAL?53.5%?.EIS results show that the NALC-8composite material exhibits low charge transfer resistance and ion diffusion resistance.