Fuel Cell Applications of Single Wall Carbon Nanotubes

Author(s):  
R. P. Raffaelle ◽  
B. Landi ◽  
T. Gennett ◽  
R. S. Morris ◽  
B. Dixon ◽  
...  

Novel carbon materials with nanometer dimensions are of potentially significant importance for a number of advanced technological applications. Currently, considerable interest exists in the possible applications of single wall carbon nanotubes (SWNTs) to proton exchange membrane (PEM) fuel cells. Proposed uses include as anode materials in both hydrogen and direct methanol fuel cells, solid polymer electrolyte additives, active cathode materials and bipolar plate interconnects. One of the desirable attributes afforded by the use of SWNTs in fuel cell applications stems from a combination of their extremely high electrical conductivity and large aspect ratios which results in a low weight percent for the electrical percolation threshold. This conductivity combined with the outstanding catalytic surface area offered by these nanostructured materials makes them a potentially outstanding active material for PEM electrodes. In addition, the high thermal conductivity, enhanced mechanical properties and corrosion resistance of polymer-SWNT composites may play a large role in developing new fuel cell designs such as thin-film microelectronic fuel cells. We will review the current applications involving SWNTs in PEM fuel cells and report on the recent work in the Nanopower Research Lab at RIT and it partners on utilizing high purity SWNT’s in microelectronic fuel cells.

Author(s):  
H. J. Ruf ◽  
B. J. Landi ◽  
R. P. Raffaelle

Considerable interest exists in the application of single wall carbon nanotubes (SWNTs) to proton exchange membrane fuel cells (PEMFCs). Proposed applications include use as anode materials in both hydrogen and direct methanol fuel cells, solid polymer electrolyte additives, active cathode materials, and bipolar plate interconnects. SWNTs have extremely high electrical conductivity and catalytic surface areas which make them potentially outstanding active materials for PEMFC electrodes. Additionally the enhanced mechanical properties may play a roll in developing new fuel cell designs such as thin-film microelectronic fuel cells. In a previous study SWNTs were combined with commercially obtained E-TEK Vulcan XC-72 and Nafion® to produce composite cathode membranes. The addition of nanotubes resulted in enhanced fuel cell performance over an equivalent weight percent doping of E-TEK alone. This increased performance was achieved with a 50% reduction in the quantity of platinum present in the cathode. In the present study we investigate fuel cell performance when both the anode and cathode membranes contain graphite, platinum and SWNTs. The SWNTs were characterized by use of thermogravimetric analysis, Raman and UV/VIS/NIR spectroscopes as well as high resolution field emission scanning electron microscopy. Fuel cell performance was determined by comparison of the IV characteristics.


Author(s):  
Supramanian Srinivasan ◽  
Lakshmi Krishnan ◽  
Andrew B. Bocarsly ◽  
Kan-Lin Hsueh ◽  
Chiou-Chu Lai ◽  
...  

Investments of over $1 B have been made for Fuel Cell R&D over the past five decades, for space and terrestrial applications; the latter includes military, residential power and heating, transportation and remote and portable power. The types of fuel cells investigated for these applications are PEMFCs (proton exchange membrane fuel cells), AFCs (alkaline fuel cells), DMFCs (direct methanol fuel cells), PAFCs (phosphoric acid fuel cells), MCFCs (molten carbon fuel cells), SOFCs (solid oxide fuel cells). Cell structure, operating principles, and characteristics of each type of fuel cell is briefly compared. The performances of fuel cells vs. competing technologies are analyzed. The key issues are which of these energy conversion systems are technologically advanced and economically favorable and can meet the lifetime, reliability and safety requirements. This paper reviews fuel cells vs. competing technologies in each application category from a scientific and engineering point of view.


Author(s):  
Mohammad Kazemi Nasrabadi ◽  
Amir Ebrahimi-Moghadam ◽  
Mohammad Hosein Ahmadi ◽  
Ravinder Kumar ◽  
Narjes Nabipour

Due to low working temperature, high energy density and low pollution, proton exchange fuel cells have been investigated under different operating conditions in different applications. Using platinum catalysts in methanol fuel cells leads to increasing the cost of this kind of fuel cell which is considered as a barrier to the commercialism of this technology. For this reason, a lot of efforts have been made to reduce the loading of the catalyst required on different supports. In this study, carbon black (CB) and carbon nanotubes (CNT) have been used as catalyst supports of the fuel cell as well as using the double-metal combination of platinum-ruthenium (PtRu) as anode electrode catalyst and platinum (Pt) as cathode electrode catalyst. The performance of these two types of electro-catalyst in the oxidation reaction of methanol has been compared based on electrochemical tests. Results showed that the carbon nanotubes increase the performance of the micro-fuel cell by 37% at maximum power density, compared to the carbon black. Based on thee-electrode tests of chronoamperometry and voltammetry, it was found that the oxidation onset potential of methanol for CNT has been around 20% less than CB, leading to the kinetic improvement of the oxidation reaction. The current density of methanol oxidation reaction increased up to 62% in CNT sample compared to CB supported one, therefore the active electrochemical surface area of the catalyst has been increased up to 90% by using CNT compared to CB which shows the significant rise of the electrocatalytic activity in CNT supported catalyst. Moreover, the resistance of the CNT supported sample to poisonous intermediate species has been found 3% more than CB supported one. According to the chronoamperometry test results, it was concluded that the performance and sustainability of the CNT electro-catalyst show remarkable improvement compared to CB electro-catalyst in the long term.


2012 ◽  
Vol 124 (28) ◽  
pp. 7104-7107 ◽  
Author(s):  
Patraporn Luksirikul ◽  
Karaked Tedsree ◽  
Mark G. Moloney ◽  
Malcolm L. H. Green ◽  
Shik Chi Edman Tsang

Author(s):  
C. W. Hong ◽  
C. H. Cheng ◽  
K. Fei

This paper describes the fundamental theory, algorithm and computation methods to predict the performance of proton exchange membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) using a simplified computational fluid dynamics (CFD) approach. Based on the common transport phenomenon inside both fuel cells, the mass, momentum, energy and species equations were derived. Darcy laws were employed to simplify the momentum equation and also to linearize the species equation. The mathematical model was solved in various flow channel designs and some membrane electrode assembly (MEA) options. The major concern is mainly on the cathode side, in the PEMFC case, that dominates the performance deterioration due to potential loss in the flow field. In the case of DMFCs, both anode and cathode sides are simulated. The methanol crossover effect is also included. This virtual performance test bench plays an important role in the prototype fuel cell design. The computer aided design tool is proved to be useful in configuration designs. Additionally, it provides the detailed transport phenomenon inside the fuel cell stack.


Author(s):  
Tao Zhang ◽  
Pei-Wen Li ◽  
Qing-Ming Wang ◽  
Laura Schaefer ◽  
Minking K. Chyu

Two types of miniaturized PEM fuel cells are designed and characterized in comparison with a compact commercial fuel cell device in this paper. One has Nafion® membrane electrolyte sandwiched by two brass bipolar plates with micromachined meander-like gas channels. The cross-sectional area of the gas flow channel is approximately 250 by 250 (μm). The other uses the same Nafion® membrane and anode structure, but in stead of the brass plate, a thin stainless steel plate with perforated round holes is used at cathode side. The new cathode structure is expected to allow oxygen (air) being supplied by free-convection mass transfer. The characteristic curves of the fuel cell devices are measured. The activation loss and ohmic loss of the fuel cells have been estimated using empirical equations. Critical issues such as flow arrangement, water removing and air feeding modes concerning the fuel cell performance are investigated in this research. The experimental results demonstrate that the miniaturized fuel cell with free air convection mode is a simple and reliable way for fuel cell operation that could be employed in potential applications although the maximum achievable current density is less favorable due to limited mass transfer of oxygen (air). The relation between the fuel cell dimensions and the maximum achievable current density is also discussed with respect to free-convection mode of air feeding.


Author(s):  
Nicholas Siefert ◽  
Chi-Hsin Ho ◽  
Shawn Litster

Liquid water management is a critical issue in the development of proton exchange membrane (PEM) fuel cells. Liquid water produced electrochemically can accumulate and flood the microchannels in the cathodes of PEM fuel cells. Since the liquid coverage of the cathode can fluctuate in time for two-phase flow, the rate of oxygen transport to the cathode catalyst layer can also fluctuate in time, and this can cause the fuel cell power output to fluctuate. This paper will report experimental data on the voltage loss and the voltage fluctuations of a PEM fuel cell due to flooding as a function of the number of parallel microchannels and the air flow rate stoichiometric ratio. The data was analyzed to identify general scaling relationships between voltage loss and fluctuations and the number of channels in parallel and the air stoichiometric ratio. The voltage loss was found to scale proportionally to the square root of the number of channels divided by the air stoichiometric ratio. The amplitude of the fluctuations was found to be linearly proportional to the number of microchannels and inversely proportional to the air stoichiometric ratio squared. The data was further analyzed by plotting power spectrums and by evaluating the non-linear statistics of the voltage time-series.


Author(s):  
Chong-Fang Ma ◽  
Hang Guo ◽  
Fang Ye ◽  
Jian Yu

As a clean, high efficiency power generation technology, fuel cell is a promising choice of next generation power device. Widely application of fuel cells will make a contribution to save fuels and reduce atmospheric pollution. In recent years, fuel cells science, technology and engineering have attracted great interest in China. There are more and more Chinese scientists and engineers embark upon fuel cell projects. The government also encourages academic institutions and companies to enter into this area. Research and development of fuel cells are growing rapidly in China. There are many chances and challenges in fuel cells’ research and development. The state of the art of research and development of fuel cells in China was overviewed in this paper. The types of fuel cells addressed in this paper included alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, proton exchange membrane fuel cells and direct methanol fuel cells.


Author(s):  
Scott A. Kenner ◽  
Nicholas M. Josefik ◽  
Scott M. Lux ◽  
James L. Knight ◽  
Melissa K. White ◽  
...  

Background: The U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (ERDC-CERL) continues to manage The Department of Defense (DoD) Residential Proton Exchange Membrane (PEM) Fuel Cell Demonstration Project. This project was funded by the United States Congress for fiscal years 2001 through 2004. A fleet of 91 residential-scale PEM fuel cells, ranging in size from 1 to 5 kW, has been demonstrated at various U.S. DoD facilities around the world. Approach: The performance of the fuel cells has been monitored over a 12-month field demonstration period. A detailed analysis has been performed cataloging the component failures, investigating the mean time of the failures, and the mean time between failures. A discussion of the lifespan and failure modes of selected fuel cell components, based on component type, age, and usage will be provided. This analysis also addresses fuel cell stack life for both primary and back-up power systems. Several fuels were used throughout the demonstration, including natural gas, propane, and hydrogen. A distinction will be made on any variances in performance based on the input fuel stock. Summary: This analysis will provide an overview of the ERDC-CERL PEM demonstration fuel cell applications and the corresponding data from the field demonstrations. Special emphasis will be placed on the components, fuel cell stack life, and input fuel characteristics of the systems demonstrated.


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