New Graphene Supercapacitors – Electric Cars
A new type of graphene supercapacitor which can store much energy as a lithium-ion battery has been developed by a team of South Korean scientists. Conventional batteries tend to take long to charge and cannot store braking energy efficiently while graphene supercapacitors stores much energy and charges in only 16 seconds. According to South Korean, they state that `these supercapacitors energy storage devices could be scaled up for manufacturing in the future for electric vehicle applications’. Car manufacturers are continuously researching on ways to improve the efficiency of their vehicles and the best option to do this is to recover and reuse the energy which would otherwise be wasted when the brakes slow down a vehicle. However, in the case of conventional batteries it is difficult and braking takes place over time scales, measured in seconds that is too quick for batteries which takes several hours to recharge and car makers need to find other options in order to store the energy. Supercapacitors seems to be the reasonable option since they can be charged quickly and then discharge the energy in a quick manner and several car manufacturers have been testing this technology. Presently supercapacitors is not ready for the open road since though they charge and discharge energy quickly, they do not store much energy.
Moreover, they also tend to wear out due to repeated use and as the interior material break down with the constant flow of charging in and out it could be a significant problem in a device which will have to be used end number of times during the lifetime of the car.Progress of electric vehicles is on and one of the enabling technologies which would be driver friendly is the battery especially lithium-ion version which has the potential of storing enough energy and provide the cars a reasonable range for driving. It is an appropriate material in storing braking energy and can be what the electric car industry may need. South Korean scientists from Gwangiu Institute of Science and Technology have made the discovery by developing a special porous kind of graphene and amazingly a single gram of this specialized graphene has bigger surface area of a basketball court and this increased surface area helps the supercapacitor to store more energy than its previous versions of the materials that had kept graphene supercapacitors out, as an alternative to lithium-ion batteries for the electric cars.
Accommodates More Electrolytes
Since there is an absence of chemicals, graphene supercapacitors tends to have a much longer life than lithium ion batteries and can charge and discharge in seconds maintaining all this over many tens of thousands of charging cycles. The team created this graphene by reducing graphene oxide particles with hydrazine in water disturbed with ultrasound while the graphene powder was packed in a coin shaped cell, dried at 140 degree Centigrade and at a pressure of 300 kg cm for 5 hours. The outcome of the graphene electrode is highly porous and with the increased surface area, it enables the electrode to accommodate more electrolytes – an ionic liquid known as EBIMF 1 M, which eventually determines the amount of charge which the supercapacitor could maintain.