Impedance Analysis of Capacitive and Faradaic Processes in the Pt/[Dema][TfO] Interface.

The electrochemical reaction kinetics, especially the oxygen reduction reaction (ORR) at the cathode, is crucial for the performance of a fuel cell. In this study, the electrochemical processes on a polycrystalline Pt electrode in the presence of protic ionic liquid (PIL) electrolyte diethylmethylammonium triflate [Dema][TfO] are investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy. Since water is continually produced during fuel cell operation, the effect of the water content in the PIL has been intensively analyzed.

Revealing Interfacial Reactions on Pt Electrodes in Ionic Liquids by In Situ Fourier-Transform Infrared Spectroscopy.

In situ monitoring of the electrolyte/electrode interfacial processes, such as the oxygen reduction reaction (ORR), is crucial for the design of electrolytes for fuel cells. In this study, we investigate the electrochemical behavior of platinum electrodes in protic ionic liquids (PILs) by means of in situ Fourier-transform infrared spectroscopy coupled with cyclic voltammetry. The result provides direct evidence of the change of water at the Pt electrode surface due to Pt oxide formation and reduction.

Self-Standing, Ultrasonic Spray-Deposited Membranes for Fuel Cells.

The polymer electrolyte membrane and its contact with electrodes has a significant effect on the performance of fuel and electrolysis cells but the choice of commercially available membranes is limited. In this study, membranes for direct methanol fuel cells (DMFCs) were made by ultrasonic spray deposition from commercial Nafion solution; the effect of the drying temperature and presence of high boiling solvents on the membrane properties was then analyzed. When choosing suitable conditions, membranes with similar conductivity, water uptake, and higher crystallinity than comparable commercial membranes can be obtained.

The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy.

Protic ionic liquids are promising electrolytes for fuel cell applications. They would allow for an increase in operation temperatures to more than 100 °C, facilitating water and heat management and, thus, increasing overall efficiency. As ionic liquids consist of bulky charged molecules, the structure of the electric double layer significantly differs from that of aqueous electrolytes.

Constructing a Multifunctional Interface between Membrane and Porous Transport Layer for Water Electrolyzers.

The cell performance and durability of polymer electrolyte membrane (PEM) water electrolyzers are limited by the surface passivation of titanium-based porous transport layers (PTLs). In order to ensure stable performance profiles over time, large amounts (≥1 mg·cm) of noble metals (Au, Pt, Ir) are most widely used to coat titanium-based PTLs. However, their high cost is still a major obstacle toward commercialization and widespread application.

Acidic Ionic Liquids Enabling Intermediate Temperature Operation Fuel Cells.

Herein we show that protic ionic liquids (PILs) are promising electrolytes for fuel cells operating in the temperature range 100-120 °C. ,-Diethyl--methyl-3-sulfopropan-1-ammonium hydrogen sulfate ([DEMSPA][HSA]), ,-diethyl--methyl-3-sulfopropan-1-ammonium triflate ([DEMSPA][TfO]), ,-diethyl-3-sulfopropan-1-ammonium hydrogen sulfate ([DESPA][HSA]), and ,-diethyl-3-sulfopropan-1-ammonium triflate ([DESPA][TfO]) are investigated in this study with regard to their specific conductivity, thermal stability, viscosity, and electrochemical properties. The [DEMSPA][TfO] and [DESPA][TfO] electrolytes offer high limiting current densities for the oxygen reduction reaction (ORR) on platinum electrodes, that is, about 1 order of magnitude larger than 98% HPO.