This is of course very promising simply because it is fast. I will not be surprised if some clever designwill also raise energy density dramatically since we are still just doing whatis tried and true.
Most important, isthat this will surely give us a rapid recharge battery that will be up to plugand play architecture. What I mean bythat is that we can design in an onboard converter to draw AC power in a fewseconds and then plug into the application. Still difficult but a fast battery make the effort worthwhile in a waythat plug and wait battery never could. There was no incentive for eliminating the hardware.
In the event, grapheneis going to be muscling into the battery party and possibly eliminating theexotics completely. To start with it isnaturally lighter, is many times faster from the beginning and starts bymatching present performance of one of the competing protocols. It is not quite yet taking full advantage of super capacitance but when yourecall that it is naturally been engineered in the appropriate dimensions it isgoing to be surprisingly easy to take forward.
There is still work tobe done here but my first thought on coming across graphene was to thinkbattery and this is beginning to flesh it out.
NOVEMBER 26, 2010
A supercapacitor withgraphene-based electrodes was found to exhibit a specific energy density of85.6 Wh/kg at room temperature and 136 Wh/kg at 80 °C (all based on the totalelectrode weight), measured at a current density of 1 A/g. These energy densityvalues are comparable to that of the Ni metal hydride battery, but thesupercapacitor can be charged or discharged in seconds or minutes. The key tosuccess was the ability to make full utilization of the highest intrinsicsurface capacitance and specific surface area of single-layer graphene bypreparing curved graphene sheets that will not restack face-to-face. The curvedmorphology enables the formation of mesopores accessible to and wettable byenvironmentally benign ionic liquids capable of operating at a voltage over 4Volts.
Technologically, the nano graphene-based, ionic liquid-enabled supercapacitorprovides a specific energy density of 85.6 Wh/kg (based on the total electrodeweight) at room temperature and 136 Wh/kg at 80°C, both measured at a currentdensity of 1 A/g (corresponding to a high charge/discharge rate).
a) These are the highest energy density values ever reported for nano carbonmaterial-based supercapaitors dominated by the electric double layer (EDL)mechanism, with minimal contribution from any redox-type pseudocapacitancemechanism.
b) These energy density values are comparable to that of the Ni metal hydridebattery. This new technology provides an energy storage device that storesnearly as much energy as in a battery, but can be recharged in seconds orminutes. We believe that this is truly a breakthrough in energy technology.
The theoretical capacitance of graphene is 550 F/g (Farads per gram).
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