The Synthesis and Characterization of Bioactive Carbon Material Supercapacitor Loaded with Nickel Hydroxide
Supercapacitor is an environmentally friendly energy storage device, which fills the gap between traditional capacitors and batteries, and its energy density and power density are higher than the battery [1]. Moreover, the supercapacitor has the characteristics of high charging and discharging efficiency and long cycle life. This makes it used in the electric vehicles, high powered weapons, standby power in electronic equipment, flash of industrial equipment and ignition device [2]. So it has great significance for the basic research, the development of electronic industry and the electric vehicle to carry out the supercapacitor electrode materials [3]. Here, we firstly prepared the activated carbon materials by carbonizing, activating the biological material, then prepared the nickel hydroxide/activated carbon composites by direct precipitation method, and studied the electrochemical properties of composite materials with different nickel hydroxide (Ni(OH)2) contents (the mass fraction). The results of cyclic voltammetry and constant current charge-discharge are that a small amount of Ni(OH)2 are mixed in the carbon surface and pores, the composite material has a good specific capacitance, stability, charging and discharging performance compared with the activated carbon. When the mass fraction of Ni(OH)2 is 12%, the supercapacitor exhibits the excellent electrochemical properties, its capacitance is up to 400.78F/g which improved 75.21% compared with the activated carbon’s capacitance (228.74F/g). 6mol/L potassium hydroxide (KOH) is used as an electrolyte, the capacitance is only reduced to 94.42% after conducting 1000 times cycle life tests. This means that the supercapacitor shows a good stability.
Research on Carbon-Based Electrode Materials for Supercapacitors
As a new type of energy storage device, supercapacitors with high specific capacitance, fast charge and discharge, and long cycle life have attracted significant attention in the energy storage field. Electrode materials are a crucial factor defining the electrochemical performance of supercapacitors. The standard supercapacitor electrode materials used can be classified into three types:carbon-based materials, metal oxides and hydroxide materials, and conductive polymers. This review introduces the principles of supercapacitors and summarizes recent research progress of carbon-based electrode materials, including pure carbon materials, and the binary and ternary complex materials with carbon.
High voltage supercapacitors using hydrated graphene film in a neutral aqueous electrolyte
Abstract The potential stability windows of chemical converted graphene in different aqueous electrolyte solutions were investigated for the first time. Based on this result, a supercapacitor with a high voltage and long cycle-life was prepared with the hydrated graphene films in the neutral aqueous solution at the maximum voltage of 1.6 and even 1.8 V. The electrochemical performance of the obtained sample was systematically investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. According to the cyclic voltammetry, hydrated graphene film can still retain rectangular shape at the high scan rate of 0.5 V/s in the neutral aqueous electrolyte. At a galvanostatic charge/discharge rate of 1 or 200 A/g, the specific capacitance of 202.3 or 138.1 F/g was delivered, respectively. Furthermore, the EIS results also confirm its fast neutral ion diffusion and high operating frequency of 9.34 Hz.