Carbon Materials for Supercapacitors Produced by Pyrolysis of Biomass Originated Synthetic Resins. Synthesis and Characterization

BARBERO; TAMBORINI, L.; G. COTELLA; ACEVEDO

Congreso; 65th Annual Meeting of the International Society of Electrochemistry; 2014

ISE

Porous carbon are widely used as supercapacitor materials, due to their large surgace areas, good conductivity and resistance to corrosion.[1] Porous glassy carbon can be obtained by pyrolysis, that is heating in inert atmosphere, of porous phenol-aldehyde resins.[2] While most phenols and aldehydes render porous gels by condensation in basic media, the gels collapse into non porous xerogels upon drying. Therefore, special drying procedures (depresurization of supercritical fluids or sublimation of frozen solvent) are used to maintain the gel porosity during drying. On the other hand, we have shown that resorcinol-formaldehyde gels can be dried in air when a pore stabilizing agent is added to the polymerization solution.[2,3] Therefore, the complex drying can be avoided if the porous matrix is stabilized. The use of monomers produced from biomass is desiderable from an ecological viewpoint. Porous carbons have been prepared by pyrolisis of resins made of tannin (a natural polyphenol) and furfural (a biomass product),[4] or tannin and formaldehyde.[5] However, supercritical or sublimation drying were needed to prepare porous dry resins. In the present communication, we describe the textural and electrochemical properties of porous glassy carbons prepared by condensation of tannin/furfural and tannin/formaldehyde. The porous gels maintain its porosity during conventional drying, obtaining large (> 500 m 2 /g) surface areas, avoiding the use of complex drying procedures. The electrochemical properties are studied using cyclic voltammetry and AC impedance. Specific capacitances larger than 200 F/g were measured. Both the textural and electrochemical properties are highly dependent on the polymerization pH and taninn/water ratio. The specific capacitance values are similar to those previously reported for resorcinol formaldehyde resins, [2,3] while biomass originated monomers are less costly and renewable. On the other hand, the specific capacitance values are similar or larger than those obtained using complex drying procedures.[4,5] References [1] E. Frackowiak, F. Béguin, Carbon, 39(2001)937 -950. [2] M.M. Bruno, N.G. Cotella, M.C. Miras, C.A. Barbero, Colloids and Surfaces A, 362(2010)28-32. [3] J. Balach, L.Tamborini, K. Sapag, D.F. Acevedo, C.A. Barbero, Colloids and Surfaces A, 415(2012)343-348 and refs therein. [4] K. Kraiwattanawong, S.R. Mukai, H. Tamon, A.W. Lothongkum, Microporous and Mesoporous Materials, 98(2007)258-266. [5] A. Szczurek, G. Amaral-Labat, V. Fierro, A. Pizzi, A. Celzard, Carbon, 49(2011)