Primena ugljeničnih materijala dobijenih karbonizacijom elektrohemijski geliranih alginata i hitozana u superkondenzatorima

Abstract

The aim of this work is to investigate the capacitive characteristics of carbon-based materials obtained by carbonization of electrochemically synthesized gels based on alginate (CA-i, CA-3i, CA-3n), chitosan (CH-i), as well as their composites (CHA-i) using cyclic voltammetry at different polarization rates. The capacitance characteristics of the examined materials were tested in 6M KOH and 0.5M H2SO4, The specific capacities of the tested materials, in an acidic medium, at a polarization rate of 2 mV / s, decrease according to the following sequence: C-A-i> C-HA-i> C-A-3i> C-A-3n> C-H-i, where the maximum value of the specific capacity is 362 F / g. Also, based on the obtained results, a large decrease in capacity was observed, accompanied by an increase in the speed of polarization of the working electrode. The capacitance properties were successfully separated using the Trasatti and Dunn methods, and the results of both methods are largely consistent. It has been shown that the dominant form of energy storage through Faraday reactions, ie the share of pseudocapacitance, is large in all materials. The highest share of double-layer capacity in acidic medium was recorded in C-H-i, while in the base medium the largest share of double-layer capacity was present in material C-A-3n, due to the fact that electrochemical activity of surface groups (oxygen and / or nitrogen) is pH-dependent.