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A TiC-derived carbon (CDC) and its partially oxidized derivative (ox-red-CDC), oxidized by a modified Hummers method, were studied as promising electrode materials for electrochemical energy storage. To evaluate the electrochemical properties of the carbon materials, cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy measurements were performed in 1 M Li2SO4 using 2- and 3-electrode cells. A partially oxidized surface was shown to improve the capacitance and electrochemical stability of a nanoporous CDC at positive potential values. The respective anodic capacitance of 80 F cm−3 reveals a 15% improvement over the non-oxidized CDC. At negative potential values, the capacitance of two carbon materials is almost equal, 97 vs. 93 F cm−3, for the non-oxidized and partially oxidized CDC materials, respectively. An asymmetric 2-electrode ultracapacitor containing ox-red-CDC as the anode and pristine CDC as the cathode demonstrated an excellent cycle life. The temporary repolarization of the 2-electrode cell after thousands of charge–discharge cycles increased the capacitance and improved the cycling characteristics, likely due to regeneration and cleaning of the electrode surface. [ABSTRACT FROM AUTHOR]

Electroreduction of oxygen in alkaline solution on glassy carbon (GC) electrodes modified with different carbon nanomaterials has been studied. Electrochemical experiments were carried out in 0.1 M KOH employing the rotating disk electrode and rotating ring-disk electrode methods. The GC disk electrodes were modified with carbon nanomaterials using polytetrafluoroethylene as a binder. Four different carbon nanomaterials were used: multiwalled carbon nanotubes, carbon black powder, and two carbide-derived carbons (CDC). For the first time, the electrocatalytic behavior of CDC materials toward oxygen reduction is explored. Electrochemical characterization of the materials showed that all the carbon nanomaterial-modified GC electrodes are highly active for the reduction of oxygen in alkaline solutions. [ABSTRACT FROM AUTHOR]

Devices using electroactive polymer-supported carbon material can be exploited as alternatives to conventional electromechanical actuators in applications where electromechanical actuators have some serious deficiencies. One of the numerous examples is precise microactuators. In this paper, we show for first time the dilatometric effect in nanocomposite material actuators containing carbide-derived carbon (CDC) and polytetrafluoroetylene polymer (PTFE). Transducers based on high surface area carbidederived carbon electrode materials are suitable for short range displacement applications, because of the proportional actuation response to the charge inserted, and high Coulombic efficiency due to the EDL capacitance. The material is capable of developing stresses in the range of tens of N cm-2. The area of an actuator can be dozens of cm², which means that forces above 100 N are achievable. The actuation mechanism is based on the interactions between the high-surface carbon and the ions of the electrolyte. Electrochemical evaluations of the four different actuators with linear (longitudinal) action response are described. The actuator electrodes were made from two types of nanoporous TiC-derived carbons with surface area (SA) of 1150 m² g-1 and 1470 m² g-1, respectively. Two kinds of electrolytes were used in actuators: 1.0 M tetraethylammonium tetrafluoroborate (TEABF4) solution in propylene carbonate and pure ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf). It was found that CDC based actuators exhibit a linear movement of about 1% in the voltage range of 0.8 V to 3.0 V at DC. The actuators with EMITf electrolyte had about 70% larger movement compared to the specimen with TEABF4 electrolyte. [ABSTRACT FROM AUTHOR]

The electrical double-layer and electrochemical characteristics at the nanoporous carbon|acetone, acetonitrile, γ-butyrolactone and propylene carbonate interfaces with addition of (C2H5)3CH3NBF4 electrolyte have been studied by cyclic voltammetry and electrochemical impedance spectroscopy methods. The region of ideal polarizability, values of series and parallel capacitances, pore resistance and other characteristics have been established. Analysis of complex impedance plane plots shows that the nanoporous carbon|1 M (C2H5)3CH3NBF4 electrolyte interface can be simulated by an equivalent circuit, in which the two parallel conduction parts in the solid and liquid phases are interconnected by the double-layer capacitance in parallel with the complex admittance of hindered reaction of the charge transfer process or of the partial charge transfer (i.e., adsorption stage limited) process. The values of the characteristic frequency depend on the electrolyte composition (i.e., on the solvent viscosity and dielectric constant) and on the electrode potential (i.e., on the Gibbs adsorption energy of the solvent molecules and ions at the surface of the nanoporous carbon electrode dependent on the electrode potential). The modified combined Frumkin–Melik-Gaikazyan and Randles-like equivalent circuit, combined Voigt and Frumkin–Melik-Gaikazyan and Newman et al. models have been used for the simulation of the complex impedance plane plots. [Copyright &y& Elsevier]