A Comparative Study of Hydrogen Storage and Hydrocarbon Fuel Processing for Automotive Fuel Cells

Abstract

In recent years, there has been increased interest in fuel cells as a promising energy storage technology. The environmental impacts due to the extensive fossil fuel consumption is becoming increasingly important as greenhouse gas (GHG) levels in the atmosphere continue to rise rapidly. Furthermore, fuel cell efficiencies are not limited by the Carnot limit, a major thermodynamic limit for power plants and internal combustion engines. Therefore, hydrogen fuel cells could provide a long-term solution to the automotive industry, in its search for alternate propulsion systems. Two most important methods for hydrogen delivery to fuel cells used for vehicle propulsion were evaluated in this study, which are fuel processing and hydrogen storage. Moreover, the average fuel cost and the greenhouse gas emission for hydrogen fuel cell (H2 FCV) and gasoline fuel cell (GFCV) vehicles are compared to that of a regular gasoline vehicle based on the Argonne National Lab’s GREET model. The results show that the average fuel cost per 100 miles for a H2 FCV can be up to 57% lower than that of regular gasoline vehicles. Moreover, the obtained results confirm that the well to wheel greenhouse gas emission of both H2 FCV and GFCV is significantly less than that of regular gasoline vehicles. Furthermore, the investment return period for hydrogen storage techniques are compared to fuel processing methods. A qualitative safety and infrastructure dependency comparison of hydrogen storage and fuel processing methods is also presented.

Electrochemical Stability Window of Imidazolium-Based Ionic Liquids as Electrolytes for Lithium Batteries

“…During the past several years, rechargeable batteries have gathered significant attention for applications ranging from plug-in hybrid vehicles to power supplies in aerospace systems. − Improving the specific energy density of lithium batteries while maintaining high safety standards for large-scale applications has always been a challenge due to the high vapor pressure and flammability of conventional organic electrolytes. Room-temperature ionic liquids, which have low vapor pressure, high thermal stability, and low flammability, are considered as a potential alternative due to remarkable safety advantages over conventional organic electrolytes. − In fact, studies investigating potential application of room-temperature ionic liquid electrolytes in lithium–ion and lithium–sulfur batteries have demonstrated cyclability and capacity improvement over the batteries operating with conventional electrolytes. − In our recent studies, we have investigated the thermodynamics and kinetics of cathodic and anodic reactions in lithium–air batteries with ionic liquid electrolytes. − In general, the electrochemical stability window of the electrolyte, defined as the difference between the solvent’s reduction and oxidation potentials, plays a crucial role in large-scale applications of lithium batteries from pure electric and/or hybrid electric vehicles to grid energy storage.…”