Preparation And Their Electrochemistry Performance Of Nickel-Based Oxide(Hydroxide) And Activated Carbon

Supercapacitors have been recognized as unique energy storage devices which have higher energy density than conventional capacitors, and higher power density than batteries, filling the gap between conventional dielectric capacitors and batteries. There are advantages of supercapacitors about release large discharge current instantly, high efficiency of charge-discharge and long cycle life. Based on the above, the promising application of supercapacitors in the fields such as mobile telecommunication, information technology, consumer electronics, electric vehicle, aviation and aerospace, and military force, have been attracting more and more attention throughout the world. It is meaningful to study on supercapacitor materials. This paper is divided into several parts:First of all, we prepared a series of nickel oxide(NiO) and its composites materials using hydrothermal process. We used a series of the measures such as X-rays diffraction(XRD), scan electronic microscope(SEM), cyclic voltammetric measurements(CV), constant charge/discharge measurements, Ac-impedance and so on to examine the structure and properties of products. By experiments we got the conclusions as follows: NiO materials were prepared via a hydrothermal process using ethylene glycol as a hydrolysis-controlling agent and polyethylene glycol (PEG1000) as a surfactant. We found that the addition of ethylene glycol can enhance the electricity, cycle reversibility and specific capacitance of NiO and its composites material, the specific capacitance of 340 F·g^-1 and 246 F·g^-1 were obtained for as-prepared materials.At the second part, this article study on activated carbon electrode materials which prepared by chemical activation from Xinjiang coal. Compared with other System, this activated carbon material has large particle size(μm), high specific surface area and higher capacity. By adding KOH and coal ratio of 3:1, compared with two-step method, activated carbon electrode material prepared by one-step method has smaller particle size, higher dispersion, higher mesopore porosity, smaller equivalent series resistance and charge transfer resistance, its better performance is more suitable for supercapacitor electrode materials. Capacity of one-step method activated carbon electrode material is 160 F·g^-1, when scan rate turn to 5 mV·s^-1. while in the same scan rate , capacity of two-step method activated carbon electrode materials is 115 F·g^-1.At the third part, NiO/ activated carbon (AC) composite materials were prepared by chemical precipitation. It can be found from examinations that the composite material obtained by coal had good properties. It has good retention of charge-discharge in large current and high capacitance. The specific capacitance is 85 F·g^-1 when scan rate turn to 150 mV·s^-1. we use eletrodeposition method to perpare Ni(OH)₂/CNTs material, after electricity test, the high specific capacitance of Ni(OH)2/CNTs material is 2637 F·g^-1 and cycle reversibility also is good.