Asymmetric systems activated carbons

The limitations of manganese dioxide in a two electrode capacitor were overcome by using activated carbon at the negative electrode. Such an asymmetric system was previously proposed13, without sufficient explanation for the performance observed. In the present study, a deep study of the mechanism of charge storage for both electrodes allowed the system to be optimized. 

Asymmetric Systems Using Two Different Activated Carbons.369... 

The first asymmetric systems presented in the literature used a rechargeable battery-type electrode combined with an activated carbon capacitive electrode, either in aqueous [99,100] or in organic [101-109] electrolytes. The reason which led to follow this direction is the possibility to enhance at the same time the cell voltage and the cell capacitance [110-112],... 

The third and the most important approach to meet the goal that is under serious investigation is to develop asymmetric (hybrid) capacitors. As shown in Fig. 4.3 various hybrid capacitor systems are possible by coupling redox-active materials (e.g., graphite [10, 31], metal oxides [5, 14], conducting polymers [17,18]), and an activated carbon (AC). There are suggested two different systems, one is aqueous and the other is non-aqueous. Some of them are listed below in Fig. 4.4. These approaches can overcome the energy density limitation of the... 

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