Jesús Palma

Carbide derived carbon electrode with natural graphite addition in magnesium electrolyte based cell for supercapacitor enhancements

Abstract Herein, we have presented a supercapacitor based on carbide derived carbon (CDC) electrode with natural graphite (NG) addition. The capacitor was analyzed at 22 °C by cyclic voltammetry, galvanostatic charge-discharge and impedance techniques using a 0.5 mol/L of magnesium (II) bis (trifluoro methanesulfonyl) imide (MgTFSI) in ethylene carbonate-propylene carbonate (EC: PC = 1: 1, v/v) as electrolyte. The results conclude that the CDC cell enhancements have been proven by the composite electrode (5%–30% NG to CDC) especially on the cell efficiency and voltage i.e., the CDC cell around 2.5 V limit was improved. An obtainable specific capacitance, real power and energy density are 15 F·g−1, 1.2 kW·kg−1 and 15 Wh·kg−1, respectively.

A 3-V electrochemical capacitor study based on a magnesium polymer gel electrolyte by three different carbon materials

An organic medium with lithium and sodium salts is not so safe in some cases. Structural features of carbon electrodes play a vital role on the capacitor parameters. Based on that above said, we have studied three kinds of supercapacitors using a gel electrolyte from 0.5xa0M of magnesium imide salt–polyethylene oxide (PEO) in propylene carbonate (PC). The cell electrodes were carbide derived carbon (CDC), PICACTIF and YECA activated carbons. The gel component interactions were viewed by infrared spectroscopy. The cell reversibility and symmetric were analyzed using cyclic voltammetry (CV) technique. Linear sweep voltammetry (LSV) technique was taken to approximate the electrolyte stability. Electrochemical impedance spectroscopy (EIS) result reflects the resistance and capacitive behavior of the cells, i.e., The YECA carbon shows a good capacitive behavior over the CDC- and PICACTIF-based cells whereas the CDC cell has shown a low resistance. Galvanostatic charge-discharge study (CD) results have shown a stable and ideal 2.5-V capacitor behavior. The capacitors have also proven an obtainable good specific capacitance, real power, and real energy density of ~25xa0Fxa0g−1, 0.7xa0kWxa0kg−1, and 25xa0W·hxa0kg−1, respectively. Moreover, the cells were tested for 3-V limit.

Photoelectrocatalytic study and scaling up of titanium dioxide electrodes for wastewater treatment

Different TiO2 photoelectrodes have been characterized and tested for the photoelectrocatalytic oxidation of methanol. Particulate electrodes (TiO2/Ti and TiO2/ITO) have been shown to notably favour charge-carrier transfer at the electrolyte interface while a thermal electrode (Ti) has been shown to favour charge-carrier separation when applying an electric potential bias according to cyclic voltammetry technique, as a consequence of differences in TiO2 surface between particulate and thermal electrodes. Particulate electrodes lead to a higher photoelectrocatalytic activity for methanol oxidation compared to that of the thermal electrode, probably due to the pure-rutile TiO2 phase composition of the latter and its lower surface area. TiO2/Ti electrode has been shown to be the most effective photoelectrode tested for methanol oxidation since its activity was improved by the combination of the particulate TiO2 layer and the high electrical conductivity of the support. Generally, photocurrent density measured in the photoelectrochemical cell seems to correlate with activity, whereas this correlation is not observed when using a larger photoelectrocatalytic reactor. In contrast, the activity obtained for the scaled-up electrode is found to be similar in terms of surface kinetic constant to that obtained at laboratory scale.