Enhanced electrochemical and structural properties of carbon cryogels by surface chemistry alteration with boron and nitrogen

Resorcinol-formaldehyde (RF) derived carbon cryogels (CCs) with narrow pore size distribution were obtained via chemical modification using ammonia borane (AB). This chemical modification was achieved by adding AB to the hydrogels during the solvent exchange stage. Nitrogen sorption analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy are used to investigate the pore structure, morphology, and electrochemical properties of the modified CCs. After pyrolysis, the AB modified CCs show an increased surface area and larger mesopore volume in comparison to the untreated precursor, In addition, a uniform porous structure with a narrow pore size distribution is produced with a mesopore diameter that does not change significantly during pyrolysis. Moreover, electric double-layer supercapacitors (EDLS) used to characterize the AB modified samples shows pseudocapacitive behavior, higher current density and capacitance. (C) 2009 Elsevier Ltd. All rights reserved.