Voltammetry measurements, room-temperature reference electrodes

Electrolytes for electrochemical devices should resist reduction and oxidation and exhibit a larger electrochemical window. The electrochemical stability of RTMS is generally measured by cyclic voltammetry at room temperature recorded in a three-electrode cell configuration using a platinum, gold, or vitreous carbon electrode as the working electrode, and Ag/AgCl (saturated in solvent) for triethylanunonium formate PILs (Fig. 7.16a) or Li for DESs based on lithium salt (Fig. 7.16b) as the reference electrode. 

Measurements of the open circuit potential (OCP) were performed by linear sweep voltammetry with the anode of the electrolyser set as the working electrode, and the cathode set as both counter and reference electrodes. The hydrogen reference electrode condition was created by saturating the catholyte with H2 gas at the room temperature. The measured OCP values were refered to the standard hydrogen electrode (SHE). Since the potential of the hydrogen reference electrode varied from SHE depending on the HC1 concentration used in the experiement, this correction was taken into account for all measured OCP. 

Apparatus Cyclic voltammetry and amperometric current-time curves were obtained with a Pine Instrument Inc., Model RDE4 bipotentiostat and Kipp Zonen BD 91 XYY recorder equipped with a time base module. All measurements were performed in a conventional single-compartment cell with a saturated calomel electrode as the reference electrode and a Pt mesh as the auxiliary electrode at room temperature. Chronoamperometry was made with EG G Princeton Applied Research potentiostat/galvanostat Model 273 equipped with Model 270 Electrochemical Analysis Software. 

For the electrochemical measurements, the copper-2% zinc alloy was mounted into epoxy (Buehler epoxide resin) by curing at room temperature for about 10 h. The finished metal surface had 1 cm2 exposed. The reference electrode probe and both high-density graphite counter electrodes were also positioned into the beaker. The working electrodes were immersed in the solutions for up to 0.5 h prior to the cyclic voltammetry for monitoring the open circuit potential. 

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