Preparation And Electrochemical Application Of Nickel Cobalt Oxide Material With Different Morphology

In this study,NiCo₂O₄ materials with different morphologies were prepared using aggregates formed by different kinds of surfactants as templates.The formation process of the material and the influencing factors were studied and discussed.The main contents are as follows:（1）NiCo₂O₄ nanorods and firework-shaped microspheres with necklace structure were prepared by hydrothermal method using SDS and CTAB as soft templates.These two kinds of NiCo₂O₄ materials with different morphologies were prepared by adjusting the content ofβ-CD in the process of preparation.By controlling the content ofβ-CD to regulate the aggregation morphology of surfactants,which further pruduce NiCo₂O₄ materials with different morphologies has not been reported.The prepared materials were characterized by various methods.It was found that the prepared materials have uniform morphology,good dispersion and large specific surface area at the same time.By further analyzing the mechanism of the whole formation process,we conclude thatβ-cyclodextrin plays an important role in the whole morphology transformation process.The electrochemical properties of supercapacitors in three electrode devices were studied by using the prepared samples as electrode materials.When the current density is 1 A g^-1,the specific capacitance of firework-shaped NiCo₂O₄ microspheres(697.5 F g^-1)is higher than that of rod-like NiCo₂O₄(525 F g^-1).When used as electrode material,the cyclic test at the scanning rate of 50 mV s^-1has good cycling stability.After 10000 cycles,the specific capacitance retention rate is 85.77%.In view of these results,it can be concluded that the firework-shaped structure has great potential application in the electrode materials of supercapacitors.At the same time,this method also provides a reliable theoretical basis for the preparation of other transition metal materials.（2）NiCo₂O₄ nanorods with different lengths were prepared by hydrothermal method using DDAB and CTAB aggregation as soft templates.In the process of preparation,NiCo₂O₄ nanorods of different lengths were prepared by adjusting the ratio of DDAB:CTAB（DDAB:CTAB ratio of 1:1 and 2:1 were recorded as NCO-1 and NCO-2）.The aggregation morphology of the surfactant was adjusted by controlling the ratio of the two surfactants,and the size of the material was finally affected.When the molar ratio of DDAB to CTAB was1:1,the diameter of the NiCo₂O₄ nanorods was about 30⁵0 nm,and the length of the nanorods was about 100²50 nm.It was formed by the aggregation of NiCo₂O₄nanoparticles with a particle diameter of 5¹5 nm.When the molar ratio of DDAB:CTAB was 2:1,the NiCo₂O₄ nanorods showed the trend of elongation.The nanorods with a diameter of 50¹00 nm,the length of the nanorods up to 600⁸50 nm are still formed by the aggregation of NiCo₂O₄ particles with a diameter of 5¹5 nm,but the length of the nanorods is different from that of NCO-1.The electrochemical properties of supercapacitors were studied by using the prepared samples as electrode materials.When the current density is 1 A g^-1,the specific capacitance of NCO-2(655 F g^-1)is higher than that of NCO-1(515 F g^-1).In view of these results,it can be concluded that NCO-2 has great application potential as electrode materials of supercapacitors.The preparation of NiCo₂O₄ materials with different morphologies is affected by various factors.