Nano Particles Make Super Capacitors Even Better
Super capacitors also called ultra capacitors and electric double layer capacitors (EDLC) are capacitors with capacitance values greater than any other capacitor type available today. They have so many advantages like virtually unlimited life cycle - cycles millions of time - 10 to 12 year life, low impedance, charges in seconds, no danger of overcharge, very high rates of charge and discharge and a high cycle efficiency (95% or more). It can act both as a capacitor and battery. It can store huge amounts of charge like a battery and provide high current densities when required like a capacitor.
#-Link-Snipped-# Its most effective usage is in conjunction with a battery so as to handle irregular power supply and power surges. Since a battery can’t handle these power surges, super capacitors are used to smoothen out the power supply. In short it can be used as a power grid buffer.
They are based on a carbon nanotube technology. The carbon technology used in these capacitors creates a very large surface area with an extremely small separation distance called nanostructured electrodes. This construction has two main drawbacks. First, these electrodes are too sensitive to work in industrial scale. Second, they require the addition of some substances that may degrade the performance. So, John Q. Xiao and his team at the University of Delaware (Newark, USA) have now developed a new method of production of electrodes for the electrochemical electrodes. The electrodes are made of nickel oxide or nickel nanocomposites. This new method, they say, is cost-effective and simple and it can also be scaled up for the industry.
First a reaction medium is to be set up. High-boiling polyalcohol, known as polyols are chosen to be used as the reaction medium. The first step is the production of nickel nanoparticles. When seed crystals are introduced into the medium, the medium covers their growth surfaces, thus forming small spherical particles. The nanoparticles are then compacted into pellets and are then arranged on one side of a very thin platinum sheet. At 250 degree Celsius, a layer of nickel oxide (NiO) is formed around the pellet due to annealing and this is the actual active layer. The result of this process is compact, stable, highly porous Ni or NiO electrodes that do not require any kind of a support. The suitable electrolyte is potassium hydroxide.
The large inner surface area is got by high granularity of the environment. It provides the ions with good diffusion pathways. But at the same time the high electrical conductivity is not disturbed since the conductive network of the metal particles is not touched.
Source: #-Link-Snipped-#
#-Link-Snipped-# Its most effective usage is in conjunction with a battery so as to handle irregular power supply and power surges. Since a battery can’t handle these power surges, super capacitors are used to smoothen out the power supply. In short it can be used as a power grid buffer.
They are based on a carbon nanotube technology. The carbon technology used in these capacitors creates a very large surface area with an extremely small separation distance called nanostructured electrodes. This construction has two main drawbacks. First, these electrodes are too sensitive to work in industrial scale. Second, they require the addition of some substances that may degrade the performance. So, John Q. Xiao and his team at the University of Delaware (Newark, USA) have now developed a new method of production of electrodes for the electrochemical electrodes. The electrodes are made of nickel oxide or nickel nanocomposites. This new method, they say, is cost-effective and simple and it can also be scaled up for the industry.
First a reaction medium is to be set up. High-boiling polyalcohol, known as polyols are chosen to be used as the reaction medium. The first step is the production of nickel nanoparticles. When seed crystals are introduced into the medium, the medium covers their growth surfaces, thus forming small spherical particles. The nanoparticles are then compacted into pellets and are then arranged on one side of a very thin platinum sheet. At 250 degree Celsius, a layer of nickel oxide (NiO) is formed around the pellet due to annealing and this is the actual active layer. The result of this process is compact, stable, highly porous Ni or NiO electrodes that do not require any kind of a support. The suitable electrolyte is potassium hydroxide.
The large inner surface area is got by high granularity of the environment. It provides the ions with good diffusion pathways. But at the same time the high electrical conductivity is not disturbed since the conductive network of the metal particles is not touched.
Source: #-Link-Snipped-#
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