Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Fuel Cell”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Solid Oxide Fuel Cells Operating on Alternative and Renewable Fuels

This DOE project at the Pennsylvania State University (Penn State) initially involved Siemens Energy, Inc. to (1) develop new fuel processing approaches for using selected alternative and renewable fuels – anaerobic digester gas (ADG) and commercial diesel fuel (with 15 ppm sulfur) – in solid oxide fuel cell (SOFC) power generation systems; and (2) conduct integrated fuel processor – SOFC system tests to evaluate the performance of the fuel processors and overall systems. Siemens Energy Inc. was to provide SOFC system to Penn State for testing. The Siemens work was carried out at Siemens Energy Inc. in Pittsburgh, PA. The unexpected restructuring in Siemens organization, however, led to the elimination of the Siemens Stationary Fuel Cell Division within the company. Unfortunately, this led to the Siemens subcontract with Penn State ending on September 23rd, 2010. SOFC system was never delivered to Penn State. With the assistance of NETL project manager, the Penn State team has since developed a collaborative research with Delphi as the new subcontractor and this work involved the testing of a stack of planar solid oxide fuel cells from Delphi.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2021

An efficient and durable anode for ammonia protonic ceramic fuel cells

Ammonia protonic ceramic fuel cells (PCFCs) have the potential to be a highly efficient power source with high energy density. However, the inadequate catalytic activity of the existing anodes for utilization of ammonia greatly limits the performance of PCFCs. In this study, we report an Fe-modified state-of-the-art Ni cermet anode with greatly enhanced activity and durability toward utilization of ammonia. Cells with an Fe-decorated Ni-BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3 (Ni–BZCYYb) anode demonstrate an excellent performance, achieving peak power densities of 0.360, 0.723, 1.257, and 1.609 W cm –2 at 550, 600, 650, and 700 °C, respectively, which reveal the highest performance of solid oxide fuel cells fueled on ammonia. In addition, the cells show an excellent durability when operated at a constant current density of 0.5 A cm –2 (or a power density of ~0.435 W cm –2 ) at 650 °C. The superior activity and durability of the Fe-modified Ni/BZCYYb anode are attributed to the alternation of NH 3 adsorption strength and N 2 desorption barrier heights, as confirmed by first-principles based mechanistic and microkinetic modeling. Our research provides a valuable guidance for the development of efficient electro-catalysts for ammonia PCFCs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1977

Improved fuel cell

Concept in fuel cell design has two cells, each with its own reactant flow fields bonded into single modular unit. Cells require fewer parts and occupy less space than conventional fuel cells, effecting easier assembly and maintenance.

Bell, W. F.↗
DOE OSTI2020

Modeling Oxygen Transport in High Surface Area Carbon Supports for Polymer-Electrolyte Fuel Cells

Here, an analytical model for resistance to oxygen transport in air electrodes containing carbon black supports with high surface area was developed by combining a Thiele modulus—effectiveness factor approach at the agglomerate scale (~150 nm) with nanoscale diffusional resistance in carbon micropores/pits (~5 nm). This paper extends an earlier model for transport resistance to platinum nanoparticles on low surface area carbon. Differences in transport resistances between catalyst layers with high and low surface area carbon blacks predicted by the model with reasonable geometric dimensions and physical properties are consistent with experimental observations.

08 HYDROGEN↗
DOE OSTI2012

Studies on phase formation, microstructure development and elastic properties of reduced NiO-8YSZ anode supported bi-layer half-cell structures of solid oxide fuel cells

Highlights: Black-Right-Pointing-Pointer Detailed study on the development of microstructure and phase in NiO-8YSZ anodes. Black-Right-Pointing-Pointer Detailed study on elastic properties at high temperatures in air/reducing atmosphere. Black-Right-Pointing-Pointer Effects of initial porosity, composition and other issues are evaluated in detail. -- Abstract: Half-cell structures of solid oxide fuel cells (SOFCs) with a thin and dense electrolyte layer of 8YSZ supported by a thick and porous NiO-8YSZ anode precursor structure were reduced in a gas mixture of 5% H{sub 2}-95% Ar at 800 Degree-Sign C for selected time periods in order to fabricate cermets with desired microstructure and composition, and to study their effects on the elastic properties at ambient and reactive atmospheres. It appears that 2 h of exposure to the reducing conditions is enough to reduce {approx}80% of NiO with an enhanced porosity value of 35%. The Ni-8YSZ cermet phase formation in the anode was analyzed with X-ray diffraction (XRD) in correlation with its microstructure. The elastic properties were determined after the reduction, at room and elevated temperatures using the impulse excitation technique. At room temperature the decrease in the Young's modulus was about 44% (after 8 h of reduction) and can be attributed mainly to the changes in the microstructure, particularly the increase in porosity from {approx}12% to 37%. Young's moduli of the as-received precursor and reduced anodes were evaluated as a function of temperature in air and reducing atmosphere. The results were explained in correlation to the initial porosity, composition and oxidation of Ni at the elevated temperatures.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Synergistic Mn-Co catalyst outperforms Pt on high-rate oxygen reduction for alkaline polymer electrolyte fuel cells

Alkaline polymer electrolyte fuel cells are a class of fuel cells that enable the use of non-precious metal catalysts, particularly for the oxygen reduction reaction at the cathode. While there have been alternative materials exhibiting Pt-comparable activity in alkaline solutions, to the best of our knowledge none have outperformed Pt in fuel-cell tests. Here we report a Mn-Co spinel cathode that can deliver greater power, at high current densities, than a Pt cathode. The power density of the cell employing the Mn-Co cathode reaches 1.1 W cm -2 at 2.5 A cm -2 at 60 °C. Moreover, this catalyst outperforms Pt at low humidity. In-depth characterization reveals that the remarkable performance originates from synergistic effects where the Mn sites bind O 2 and the Co sites activate H 2 O, so as to facilitate the proton-coupled electron transfer processes. Such an electrocatalytic synergy is pivotal to the high-rate oxygen reduction, particularly under water depletion/low humidity conditions.

25 ENERGY STORAGE↗
DOE OSTI2016

A review on the performance and modelling of proton exchange membrane fuel cells

Proton Exchange Membrane Fuel Cells (PEMFC), are energy efficient and environmentally friendly alternative to conventional energy conversion for various applications in stationary power plants, portable power device and transportation. PEM fuel cells provide low operating temperature and high-energy efficiency with near zero emission. A PEM fuel cell is a multiple distinct parts device and a series of mass, energy, transport through gas channels, electric current transport through membrane electrode assembly and electrochemical reactions at the triple-phase boundaries. These processes play a decisive role in determining the performance of the Fuel cell, so that studies on the phenomena of gas flows and the performance modelling are made deeply. This paper gives a comprehensive overview of the state of the art on the Study of the phenomena of gas flow and performance modelling of PEMFC.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Liquids-to-Power Using Low-Temperature Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) operating at high temperatures (>800°C) have been overlooked in the past for automotive applications, primarily due to their longer start-up times and inability to load follow (quickly respond to varying power demands). However, lower operating temperature SOFCs (LT-SOFCs) enable more rapid start-up and several other benefits. Additionally, the rapid deployment of cost-effective LT-SOFC technology for automotive applications relies on the utilization of conventional ‘‘drop-in’’ fuels (e.g., gasoline, diesel, ethanol etc.), that adapts the existing fuel distribution infrastructure. In particular, the liquid-fed LT-SOFCs have the potential to deliver higher “well-to-wheels” fuel conversion efficiencies than H 2 -fed fuel cells as well as take advantage of the higher fuel energy density. Therefore, this review focuses on the benefits/challenges of low-temperature SOFCs (350–650°C) running on liquid fuels. The critical role of anodes and requirements/status of advanced anode materials for the direct utilization of liquid fuels in LT-SOFCs are highlighted.

25 ENERGY STORAGE↗