Proton Exchange Membrane Technology Research Articles

(Industrial Electrochemistry & Electrochemical Engineering Division New Electrochemical Technology (NET) Award) Development of Large Scale Commercial PEM Electrolysis

Proton Energy Systems (d/b/a Proton OnSite) was founded in 1996, based on the premise that hydrogen generation from proton exchange membrane (PEM)-based electrolysis cells could be made cost competitive versus existing solutions. From small scale laboratory generators, Proton has successfully scaled up products over several design generations. A key advance has been the development of Proton’s C Series, a 30 Nm3/hr or 65 kg/day hydrogen generator based on PEM technology. A building block of this size is more suited for many applications, including common industrial markets and fueling infrastructure for small fleets of cars. This presentation will describe the evolution of Proton’s electrolyzer technology, including improvements in cell stack technology, balance-of-plant scale up, and the strong product platform we have built leading to our next product scale-up effort, for megawatt scale electrolysis applications. Market drivers and applications for various unit capacities, especially the C Series, will also be discussed. Electrolysis based on PEM technology was initially used in space and underwater for life support applications. Reliability is therefore a key characteristic of these systems. Proton has demonstrated over 50,000 hours of continuous operation in house, and has over 2000 systems fielded across product lines, with excellent reliability and up time. An advantage of the PEM systems in general is the ability to generate and electrochemically compress hydrogen at differential pressure, enabling low pressure on the oxygen side of the cell and inexpensive plastic components. The non-corrosive electrolyte also enables low maintenance cost and simpler balance-of-plant. Commercial applications for on-site hydrogen generation are driven by factors such as the desire for low hydrogen inventory, high purity hydrogen requirements, and lack of easily accessible hydrogen delivery infrastructure. Proton’s initial systems were designed to replace helium as the carrier gas in gas chromatographs, or as the lifting gas in weather balloons. The H Series, the precursor to the C Series, was developed specifically to address the electric generator cooling market. Hydrogen is utilized as a cooling fluid for the windings of over 16,000 power plant generators worldwide due to its high heat capacity and low density. Many of these plants are in areas with no reliable hydrogen delivery infrastructure. By 2006, Proton had established a robust cell design leveraging many of the design principles used today. The C Series was developed to serve larger power plants as well as the next level of fueling demonstrations, including small fleets of fuel cell vehicles and fuel cell buses. In addition, it is an appropriate size for heat treating and semiconductor applications. The cell stack, the core technology for the electrochemical system, was originally developed as a replacement for the existing electrolysis stack design for oxygen generation on board submarines. Proton was selected as the preferred developer based on our water electrolysis cell technology knowledge and expertise, leading to the development of a new, larger active area cell stack, including new flow field materials for the hydrogen side of the cell and a thinner cell configuration. This design effort was completed in 18 months, from early 2008 to 2009. Proton is currently under contract to manufacture cell stacks for several submarine platforms. This new cell architecture was then modified for the commercial application, and used as the basis for designing the new C Series system configuration. On the systems side, funding from the U.S. Army / TARDEC led to the development of key balance-of-plant subsystems, such as the implementation of a new gas/water management system, as well as a new high efficiency power supply configuration to drive the cell stacks. Internal investment from Proton paid for the development of system controls, manufacturing processes, and all of the quality documentation and third party agency certification testing required to release this platform as a commercial product. This development effort also spanned about 18 months, from 2009 to early 2011. Currently, Proton is working to translate many of the material advancements from PEM fuel cells to PEM electrolysis cells. While some changes will require modification, there are significant cost savings and efficiency improvements still possible, which Proton has demonstrated to have feasibility. In addition, Proton is performing another scale up effort to launch a megawatt scale product, representing another order of magnitude increase in hydrogen output. These systems will be designed based on requirements for emerging energy markets such as renewable energy capture and biogas methanization, and will also be discussed in this talk. Figure 1

Fuel cell mobile lighting: A fuel cell market transformation project

We report the results of a project aimed to introduce proton exchange membrane (PEM) hydrogen fuel cell technology into aviation ground support equipment (GSE) and rental construction equipment. The purpose of the project was to design, build, field-test and then commercialize fuel cell equipment that is superior to its diesel counterpart. The commercializing of this hydrogen-based technology will help to start the process of displacing diesel fuel use in aviation GSE and in mobile construction equipment. We describe a hydrogen fuel cell mobile lighting tower (H2LT) that combines hydrogen stored as a high pressure gas, PEM fuel cell technology, and advanced lighting into a single unit with uses in aviation and construction. We assembled a project team of 15 institutional partners combining new technology expertise (hydrogen, fuel cells), equipment mass manufacturing capability (mobile light towers, lighting) and influential end-users to field test the H2LT in real-world use in diverse environments. Seed funding provided by Boeing enabled additional funding from the U.S. Department of Energy (DOE) and a preponderance of in-kind contributions from the industrial partners. Prototype units were constructed and field tested in the entertainment industry, at the San Francisco International Airport, at the NASA Kennedy Space Center, with the California Department of Transportation (Caltrans), and with the Connecticut Department of Transportation. The goals of these approximately year-long field tests were to assess operation of the H2LT technology in a wide variety of potentially corrosive environments (cold, wet, hot, humid, salty air) performing a wide variety of tasks, to reduce diesel emissions at these locations, and to help promote hydrogen PEM technology in new influential markets. The H2LT proved to be exceptionally durable in these diverse environments, demonstrating the compatibility of PEM fuel cells and high-pressure hydrogen storage with the construction equipment application. Results from the field tests are discussed, including system performance (efficiency, duration, durability) and the efficacy of refueling the system by different methods (H2 stations, mobile refueling). The H2LT system is compared directly to a comparable diesel-fueled light tower with regard to size, performance and emissions savings. Overall, end users were pleased with the performance of the H2LT, noting the lack of emissions and exceptionally low noise level. Recommendations for improvement were also collected and will be discussed. Two types of lighting used on the H2LT (plasma, LED) were characterized by U.C. Davis in collaboration with Caltrans. LED lighting was found to be the most energy efficient and robust lighting technology for the highly mobile H2LT application. The technical “lessons-learned” are reviewed, along with the plans for commercialization of the H2LT technology by Multiquip Inc. Finally, the benefits to the industrial participants of the project organization are described.

Advances in Proton Exchange Membrane Technology

Significant advances in low humidity and high temperature operation of proton exchange membrane fuel cells have been achieved by using a novel polymeric composite membrane based on Nafion® perfluorosulfonic acid (PFSA) copolymer. A fundamental understanding of the microstructure of currently used ePTFE reinforced Nafion® perfluorosulfonic acid (PFSA) copolymer and how the microstructure limits the high temperature and low humidity performance is discussed. Fuel cell performance data and mechanical stability data of the new composite membrane are also presented in this paper.

Detection of Flooding and Drying inside a PEM Fuel Cell Stack

Proton Exchange Membrane (PEM) fuel cells are currently seen as the most suitable choice for implementation into daily-use applications. However, the PEM technology does not yet fulfill all the necessary requirements that the mass-market demands and proper strides towards elimination of remaining issues have to be taken. Hence, in this paper, the focus is made on water management faults, i.e. flooding and drying. More precisely, it deals with detection of them with the use of Electrochemical Impedance Spectroscopy (EIS). The EIS was successfully applied as a diagnostic tool to a fuel cell stack consisted of 80 cells without usage of any special purpose measurement equipment, where, in addition to the stack current, only voltage of the complete stack was measured. The paper describes the modifications that were made on the EIS to make it capable of handling the diagnostics of fuel cell stacks. The results of the experimental study show that the approach is successful in detecting the flooding and drying faults and that for detection only excitation signals with frequencies between 30 and 300 Hz are required. Based on the experimental data and conclusions, a diagnostic decision algorithm is proposed.

Ni–Mo Nanopowders for Efficient Electrochemical Hydrogen Evolution

Earth-abundant metals are attractive alternatives to the noble metal composite catalysts that are used in water electrolyzers based on proton-exchange membrane technology. Ni–Mo alloys have been previously developed for the hydrogen evolution reaction (HER), but synthesis methods to date have been limited to formation of catalyst coatings directly on a substrate. We report a method for generating unsupported nanopowders of Ni–Mo, which can be suspended in common solvents and cast onto arbitrary substrates. The mass-specific catalytic activity under alkaline conditions approaches that of the most active reported non-noble HER catalysts, and the coatings display good stability under alkaline conditions. We have also estimated turnover frequencies per surface atom at various overpotentials and conclude that the activity enhancement for Ni–Mo relative to pure Ni is due to a combination of increased surface area and increased fundamental catalytic activity.

Advances in Proton Exchange Membrane Technology

not Available.

Advances in Proton Exchange Membrane Technology for High Efficiency Electrolysis

not Available.

Scientific and engineering issues related to PEM technology: Water electrolysers, fuel cells and unitized regenerative systems

Proton exchange membrane (PEM) technology is used in water electrolysers, H2/O2 fuel cells and unitized regenerative fuel cells (URFCs). Such electrochemical devices are of particular interest in view of the so-called hydrogen economy. Several prototypes (kW power range) have been developed and tested in the course of the GenHyPEM project (2005–2008), a STREP research program financially supported by the Commission of the European Communities in the frame of the sixth Framework Programme. The purpose of this communication is to report on the current status of each device in terms of performances and technological development. Current limitations and future perspectives are discussed.

Development and preliminary testing of a unitized regenerative fuel cell based on PEM technology

Results related to the development and testing of a unitized regenerative fuel cell (URFC) based on proton-exchange membrane (PEM) technology are reported. A URFC is an electrochemical device which can operate either as an electrolyser for the production of hydrogen and oxygen (water electrolysis mode) or as a H2/O2 fuel cell for the production of electricity and heat (fuel cell mode). The URFC stack described in this paper is made of seven electrochemical cells (256 cм2 active area each). The nominal electric power consumption in electrolysis mode is of 1.5 kW and the nominal electric power production in fuel cell mode is 0.5 kW. A mean cell voltage of 1.74 V has been measured during water electrolysis at 0.5 A cm−2 (85% efficiency based on the thermoneutral voltage of the water splitting reaction) and a mean cell voltage of 0.55 V has been measured during fuel cell operation at the same current density (37% electric efficiency based on the thermoneutral voltage). Preliminary stability tests are satisfactory. Further tests are scheduled to assess the potentialities of the stack on the long term.

PEM water electrolyzers: From electrocatalysis to stack development

Proton Exchange Membrane (PEM) water electrolysis can be used to produce hydrogen from renewable energy sources and can contribute to reduce CO 2 emissions. The purpose of this paper is to report on recent advances made in PEM water electrolysis technology. Results obtained in electrocatalysis (recent progresses made in low-cost electrocatalysis offer new perspectives for decentralized and domestic applications), on low-cost membrane electrode assemblies (MEAs), cell efficiency, operation at high current density, electrochemical performances and gas purity issues during high-pressure operation, safety considerations, stack design and optimization (for electrolyzers which can produce up to 5 Nm 3 H 2 /h) and performance degradations are presented. These results were obtained in the course of the GenHyPEM project, a 39 months long (2005–2008) research program supported by the European Commission. PEM technology has reached a level of maturity and performances which offers new perspectives in view of the so-called hydrogen economy.

Meeting the challenges in the transport sector

This paper provides an industry leader's perspectives on the potential for transportation fuel cells, reviewing their development progress, describing their advantages and barriers, and identifying paths to successful commercial deployment. UTC Power has developed proton exchange membrane (PEM) fuel cell technology for transportation since 1998, building upon applicable innovations from the company's space fuel cell and stationary fuel cell programs. PEM fuel cell durability improvements are discussed, highlighting achievements in the understanding of decay mechanisms and the design of effective mitigations. The potential for high-volume production to make automotive fuel cells cost competitive with internal combustion engines is explained. The paper underscores the important role that initial deployment of PEM technology for transit buses can play, although development of automotive fuel cells must continue in parallel as the hydrogen infrastructure develops. Suggestions are offered on how policies and regulations, communication and education, and improved codes and standards can all help to promote the widespread use of fuel cells in transportation.

Stacking Up

This article reviews that efficiency on a small scale and a means of curbing emissions make fuel cells an investment for the future. The Connecticut Clean Energy Fund put up the $1.25 million to purchase the fuel cell-power plant from a local company, Fuel Cell Energy Inc., in Danbury. The motive for funding fuel cells goes beyond boosting for local industry, though. As pressures mount on available resources and the environment, fuel cell systems can play a major role in the future of stationary and mobile power generation. Many adherents believe that fuel cell systems promise to provide benefits in a variety of applications. Systems based on PEM and direct methanol technology promise to make power more portable and convenient, and proton exchange membrane (PEM) technology also promises to provide a more efficient, cleaner technology for the automotive industry. PEM, phosphoric acid, molten carbonate, and solid oxide fuel cells are likely to be applied in cogeneration applications that use the exhaust heat.