Preparation Of Nickel-based Electrode Material And Its Capacitance Performance

As we all know,the electrode materials are core component of supercapacitor.The transition metal nickel and its compounds not only have excellent electrochemical properties,but also have the characteristics of low price,wide source,and environmental friendliness,which has become a research focus of electrode materials.The nickel metal,nickel-based sulfide and nickel-based oxalate are used as research objects in this paper.The morphology and electrochemical performance of nickel-based composites were improved by optimizing the process parameters.The specific work is as follows:?1?The green precursor was synthesized by a starch-assisted hydrothermal method and then heat-treated to prepare ultra-thin carbon nanosheets and nickel quantum dot composite materials?C-Ni-QDs?.The high conductivity of ultra-thin carbon nanosheets and the high reactivity of nickel quantum dots were used to improve their capacitance characteristics.Results show that the specific capacitance of C-Ni-QDs electrode can reach 1220 F/g at a current density of 2 A/g,and remain a retention rate of 81.3%at a current density of 20 A/g.At the same time,it also has excellent cycle life,after 2000 cycles,the capacitance retention rate is 97.0%.?2?The?,?-Ni S composite materials were synthesized via a starch-assisted hydrothermal method.The morphology of the composite materials were controlled by changing the amount of starch addition,and then the effect of the microstructure on its capacitive characteristics was studied.The results show the materials exhibit a chain-like morphology composed of nanoparticles and have good capacitance characteristics when the amount of starch addition is 1 g.The specific capacitance can reach 1240 F/g at a current density of 2 A/g,and the capacitance retention rate after2000 cycles at 3 A/g is 86.5%.?3?The Ni S/Ni₃S₄composite materials were synthesized by hydrothermal method.The microstructure of the composite materials were controlled by changing the amount of hydrazine hydrate,and its effect on the capacitance characteristics was studied.Results show that a novel 2D/3D interconnect structure can be obtained,in which 3D graded microspheres are embedded in the interconnected 2D nanosheets when 4 microliters of hydrazine hydrate is added.The materials have a high specific capacitance and excellent cycle life.Its specific capacitance is as high as 1796 F/g at 1A/g,and the cycle capacitance retention rate is 80.5%of the initial value after 1000cycles.?4?Based on the different crystallization habits of Co C₂O₄·2H₂O and Ni C₂O₄·2H₂O,Co_1-xNi_xC₂O₄·2H₂O solid solution co-existing with orthogonal monoclinic phase was prepared by chemical co-precipitation.The effects of different morphology and electrochemical performance were studied by changing different nickel-cobalt ratios.The results show that Co_0.5Ni_0.5C₂O₄·2H₂O exhibits a layered flower-like morphology and has excellent capacitance performance when the nickel-cobalt ratio is 0.5:0.5.It can provide a specific capacitance of 1226 F/g at 1 A/g and 82.9%of the capacitance remains at 20 A/g.It also has an excellent cycle life,which is specifically expressed as a capacitance retention rate of 84.6%after 3000cycles at 10 A/g.This paper has 36 figures,3 tables and 132 references.