Activated carbon nanoporous texture

Texier-Mandoki, N., J. Dentzer, T. Piquero, S. Saadallah, P. David, C. Vix-Guterl, Hydrogen storage in activated carbon materials Role of the nanoporous texture. Carbon 42(12-13), 2744-2747 2004. 

Raymundo-Pinero E, Kierzek K, Machnikowski J, and Beguin F. Relationship between the nanoporous texture of activated carbons and their capacitance properties in different electrolytes. Carbon, 2006 44(12) 2498-2507. 

This chapter intends to discuss the fundamental role played by carbons, taking particularly into account their nanotexture and surface functionality. The general properties of supercapacitors are reviewed, and the correlation between the double-layer capacitance and the nanoporous texture of carbons is shown. The contribution of pseudocapacitance through pseudofaradaic charge transfer reactions is introduced and developed for carbons with heteroatoms involved in functionalities able to participate to redox couples, e.g., the quinone/hydroquinone pair. Especially, we present carbons obtained by direct carbonization (without any further activation) of appropriate polymeric precursors containing a high amount of heteroatoms. 

Industrial supercapacitors are essentially based on nanoporous carbon electrodes. The reasons of the choice lie in the high availability, low cost, chemical inertness, and good electrical conductivity of activated carbons, as well as a high versatility of texture and surface functionality. For these reasons, this chapter will present the capacitance properties of carbon-based electrodes showing optimization strategies playing on the structure/nanotexture of carbon and the nature of the electrolyte. 

In the case of a low content of carbon deposits (Cq ==0.5 wt%) formed at a surface of nanosilica, the amount of bound water increases but it decreases at large Q values due to hydrophobic properties of carbon deposits. The properties of carbon deposits on silica are similar to that of carbon black but in the case of cataly tically active substrate or the presence of metals in the precursors (forming a cataly tically active phase) the texture of carbon can be different from carbon black. For water bound to carbon particles, a certain up-held shift can be observed due to the effects of the jt-electrons current at the carbon sheets (small graphene clusters). However, this shift is not larger as in the case of nanoporous AC because carbon deposits do not have nanopores. 

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