Supercapacitors efficiency

Under severe conditions (above 700°C), a potassium vapor is formed. It plays a special role in the activation of carbonaceous materials, easily penetrating in the graphitic domains that form cage-like micropores. The efficient development of micropores, which often gives a few-fold increase of the total specific surface area, is very useful for the application of these materials in supercapacitors [13-14]. 

The contribution by Rouzaud et al. teaches to apply a modified version of high resolution Transmission Electron Microscopy (TEM) as an efficient technique of quantitative investigation of the mechanism of irreversible capacity loss in various carbon candidates for application in lithium-ion batteries. The authors introduce the Corridor model , which is interesting and is likely to stimulate active discussion within the lithium-ion battery community. Besides carbon fibers coated with polycarbon (a candidate anode material for lithium-ion technology), authors study carbon aerogels, a known material for supercapacitor application. Besides the capability to form an efficient double electric layer in these aerogels, authors... 

Recent reports describe the use of various porous carbon materials for protein adsorption. For example, Hyeon and coworkers summarized the recent development of porous carbon materials in their review [163], where the successful use of mesoporous carbons as adsorbents for bulky pollutants, as electrodes for supercapacitors and fuel cells, and as hosts for protein immobilization are described. Gogotsi and coworkers synthesized novel mesoporous carbon materials using ternary MAX-phase carbides that can be optimized for efficient adsorption of large inflammatory proteins [164]. The synthesized carbons possess tunable pore size with a large volume of slit-shaped mesopores. They demonstrated that not only micropores (0.4—2 nm) but also mesopores (2-50 nm) can be tuned in a controlled way by extraction of metals from carbides, providing a mechanism for the optimization of adsorption systems for selective adsorption of a large variety of biomolecules. Furthermore, Vinu and coworkers have successfully developed the synthesis of... 

Braking energy is preferably recovered in supercapacitors with an efficiency of 90%. 

Amongst the various options, the fuel cell is the most promising in that it is intrinsically scalable, maintaining high efficiency at both low and high powers, and further it is modular in that from a basic module the total power can be increased to any level by cormecting several modules in series. On the negative side it has a relatively low power density and therefore it is usually coupled with a supercapacitor... 

Figure 9 shows the discharge curves of a Type I polypyrrole-based, a Type II polypyrrole/poly(3-methylthiophene)-based and a Type III poly(dithieno[3,4-6 3, 4 -d]thiophene-based supercapacitor at 4 mA cm discharge current. Types I and II can be assembled using such conventional heterocyclic polymers as polypyrrole, polyaniline and polythiophene, which are efficiently p-dopable polymers and can easily be chemically or electrochemically synthesized from inexpensive... 

Figure 10. Symmetric supercapacitor with composite poly(3-methylthiophene)-carbon-binder electrodes, a) Delivered charge ( ) and coulombic efficiency (o) of galvanostatic cycles (from 2000th to 5000th) at 5 mA cm between 0 and 3.1 V b) potential profiles of supercapacitor (solid line), and of positive (broken line) and negative (dotted line) electrodes during the 2000th galvanostatic cycle.

Supercapacitors [75,76] and fuel cells [77,78] have also been proposed for road vehicles, but are not expected to be widely used in the present decade. As an auxiliary power unit (APU), a fuel cell could replace the alternator for the generation of electrical energy. The motivation for this change would be higher overall efficiency. 

MER 13] Merlet C., Pean C., Rotenberg B., et al, Hidden ions store charge more efficiently in supercapacitors . Nature Communications, vol. 4, p. 2701, 29 October 2013. 

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