The Preparation And Electrochemical Performance Of NiCo LDH Composite With Three-dimensional Hierarchical Structure

Supercapacitors are expected to play an important role in the field of green energy development due to their low application cost,high cycle efficiency,good stability and long service life.Electrode material is the core device of supercapacitor,its microstructure and material composition directly affect the electrochemical properties of supercapacitors.In recent years,the preparation of three-dimensional multistage composite electrode structure has been considered as a feasible strategy.In this paper,a unique three-dimensional multistage structure composite electrode material was constructed by optimizing the composition ratio of different materials and adjusting the microstructure of the electrode material,which could improve the disadvantage of the single structure electrode material.At the same time,the electrochemical performance of composite electrode materials has been greatly improved due to the synergistic effect between the multistage structure and different materials.The main research contents of this paper are as follows:?1?Firstly,NiCo LDH nanosheets porous structure was grown on the surface of carbon cloth?CC?as"nucleus".Secondly,the thin Ni?OH?₂ nanosheets were deposited on NiCo LDH nanosheets to form a"shell"by constant current deposition method,and obtained the core-shell heterostructure NiCo@Ni?OH?₂ composite electrode material.Finally,the structural characterization and electrochemical properties characterization of the composite electrode materials were measured.The structural characterization confirmed that the heterostructure of three-dimensional core-shell was prepared successfully.Electrochemical tests showed that NiCo@Ni?OH?₂ composite electrode was a good electrode material.At the current density of 10 m A/cm²,the area ratio capacitance of NiCo@Ni?OH?₂ composite electrode was up to 8.6 F/cm².Even at the high current density of 50 m A/cm²,the composite electrode still keeped 69%of initial capacitance.Therefore,NiCo@Ni?OH?₂ composite electrode had outstanding rate performance and excellent cyclic stability.?2?A unique three-dimensional multistage composite electrode material was prepared.Firstly,basic cobalt carbonate nanosheets?CCH NS?were synthesized on the surface of CC by hydrothermal method.Secondly,the active material NiCo LDH were deposited on the surface of CC@CCH NS by optimizing the molar feed ratio of Ni²⁺and Co²⁺in the electrodeposition solution.Then the three-dimensional multistage structure CC@CCH NS@NiCo LDH?CC@CCH@NC-DH?composite electrode material was obtained.Finally,the structure characterization and electrochemical properties of CC@CCH@NC-DH composite electrode were measured.Experimental CC@CCH@NC-DH electrode had more optimal microstructure and electrochemical performance.When the current density was 10 m A/cm²,the area specific capacitance was 7.71 F/cm²,even if the current density increased to 50 m A/cm²,the composite electrode still had a good rate performance?72%?,and after 5000 cycles at 35m A/cm²,the capacitance retention of CC@CCH@NC-DH electrode was 82.6%.