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Oxidative steam reforming of ethanol is an important process for on board production of hydrogen in fuel cell based auxiliary power systems. Although the process has been extensively studied from a catalyst perspective, accurate models that capture species and temperature information required by model-based control algorithms during operation have not yet been developed adequately. In this work, we develop a reduced micro-kinetic model for ethanol oxidative steam reforming, which can be used in computational fluid dynamics (CFD) studies and subsequently to develop model-based control strategies. We experimentally study cordierite monolith based reactors in which Rh/CeO2 catalysts are prepared by the solution-combustion method. The catalyst system is characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), temperature programmed reduction and temperature programmed desorption analyses. The experimental reformer design enables measurement of species concentrations at various points along the reactor length, along with radial temperature profiles. A micro-kinetic model is adapted from the literature and validated against these experiments, with good agreement. The model results suggest a linear activation pathway for ethanol over rhodium catalysts by forming ethoxide, acetyl and acetate intermediates. After formation of single carbon species, the methane reforming pathway is followed. We expect that these studies, when coupled with transient studies will help in formulating model-based control strategies for ethanol reformers in complex fuel cell systems., by Renika Baruah, Marm Dixit, Anand Parejiya, Pratik Basarkar, Atul Bhargav and Sudhanshu Sharma

Today, the burgeoning drive towards global urbanization with over half the earth’s population living in cities, has created major challenges with regards to intracity and intercity transit and mobility. This problem is compounded due to the fact that almost always urbanization and increase in standard of living drives individual automobile ownerships. Over 95% of automobiles are presently powered by some form of fossil fuel and as an unintended consequence, urban centers have also been centers for peak greenhouse gas emissions, a major contributor to global climate change. A revolutionary solution to this conundrum is flight capable electric automobiles or electric aerial vehicles that can tackle both urban mobility and climate change challenges. For such advanced electric platforms, energy storage and delivery component is the vital component towards achieving takeoff, flight, cruise, and landing. The requirements and duty cycle demands on the energy storage system is drastically different when compared to the performance metrics required for terrestrial electric vehicles. As the widely deployed lithium ion-based battery systems are often the primary go-to energy storage choice in electric vehicle related applications, it is imperative that performance metrics and specifications for such batteries towards areal electric vehicles need to be established. In this nascent field, there exists ample opportunities for battery material innovations, understanding degradation mechanism, battery design, development and deployment of battery control and management systems. Thus, this chapter comprehensively discusses battery requirements and identifies battery material chemistries suitable for handling aerial electric automobile duty cycles. The chapter also discusses the battery cell-level metrics pertaining to electrochemical, chemical, mechanical, and structural parameters. Furthermore, specific models for battery degradation, state of health (SOH), capacity and models for full cell performance and degradation are also discussed here. Finally, the chapter also discusses battery safety and future directions of batteries that would power these next generation urban electric aircrafts.

Solid-state battery (SSB) is the new avenue for achieving safe and high energy density energy storage in both conventional but also niche applications. Such batteries employ a solid electrolyte unlike the modern-day liquid electrolyte-based lithium-ion batteries and thus facilitate the use of high-capacity lithium metal anodes thereby achieving high energy densities. Despite this promise, practical realization and commercial adoption of solid-state batteries remain a challenge due to the underlying material and cell level issues that needs to be overcome. This chapter thus covers the specific challenges, design principles and performance improvement strategies pertaining to the cathode, solid electrolyte and anode used in solid state batteries. Perspectives and outlook on specific applications that can benefit from the successful implementation of solid-state battery systems are also discussed. Overall, this chapter highlights the potential of solid-state batteries for successful commercial deployment in next generation energy storage systems.