to Fuel Cells.- Electro-Analytical Techniques in Fuel Cell Research and Development.- Polymer Electrolyte Membrane Fuel Cell.- Fundamentals of Gas Diffusion Layers in PEM Fuel Cells.- Water Problem in PEMFC.- Micro Fuel Cells.- Direct Alcohol and Borohydride Alkaline Fuel Cells.- Phosphoric Acid Fuel Cell Technology.- Carbonate Fuel Cell: Principles and Applications.- Direct Conversion of Coal Derived Carbon in Fuel Cells.- Solid Oxide Fuel Cells: Principles, Designs and State-of-the-Art in Industries.- Materials for Solid Oxide Fuel Cells.- Fuel Cell Power-Conditioning Systems.- Future Directions of Fuel Cell Science and Technology.

Recent Trends in Fuel Cell Science and Technology

This disclosure is concerned with thin gas diffusion electrodes comprising an open pore carbon cloth substrate provided with a uniform mixture of catalytic carbon particles and preferably Teflon particles adhered within the cloth poes and to the yarns of the cloth; processes for making and using the same; and assemblies comprising said electrodes and closely spaced preferably noble metal current collecting contacts for use in electrochemical cells operating at high current densities.

Thin carbon-cloth-based electrocatalytic gas diffusion electrodes, processes, and electrochemical cells comprising the same

A method for making an electrochemical cell electrode involves depositing a layer of dry carbon/hydrophobic polymer floc powder on the surface of a substrate by dispersing the powder as a cloud in a chamber over the substrate and pulling the powder onto the substrate by drawing a vacuum under the substrate. The electrode is subsequently compacted and sintered. Typically the carbon component of the floc is catalyzed, such as with platinum. Thus, the method is for applying a catalyst layer on an electrode substrate. The method is particularly adapted to the high speed manufacture of electrodes.

Dry floc method for making an electrochemical cell electrode

The present invention relates to particle and nanoparticle composites useful as oxygen-reduction electrocatalysts. The particle composites are composed of a palladium or palladium-alloy particle or nanoparticle substrate coated with an atomic submonolayer, monolayer, bilayer, or trilayer of zerovalent platinum atoms. The invention also relates to a catalyst and a fuel cell containing the particle or nanoparticle composites of the invention. The invention additionally includes methods for oxygen reduction and production of electrical energy by using the particle and nanoparticle composites of the invention.

Platinum- and platinum alloy-coated palladium and palladium alloy particles and uses thereof

Ionomer impregnation represents a milestone in the evolution of polymer electrolyte fuel cell (PEFC) catalyst layers. Ionomer acts as the binder, facilitates proton transport, and thereby drastically improves catalyst utilization and effectiveness. However, advanced morphological and functional characterizations have revealed that up to 60% of Pt nanoparticles can be trapped in the micropores of carbon support particles. Ionomer clusters and oxygen molecules can hardly enter into micropores, leading to low Pt utilization and effectiveness. Moreover, the ionomer thin-films covering Pt nanoparticles can cause significant mass transport loss especially at high current densities. Ionomer-free ultra-thin catalyst layers (UTCLs) emerge as a promising alternative to reduce Pt loading by improving catalyst utilization and effectiveness, while theoretical issues such as the proton conduction mechanism remain puzzling and practical issues such as the rather narrow operation window remain unsettled. At present, the development of PEFC catalyst layer has come to a crossroads: staying ionomer-impregnated or going ionomer-free. It is always beneficial to look back into the past when coming to a crossroads. This paper addresses the characterization and modeling of both the conventional ionomer-impregnated catalyst layer and the emerging ionomer-free UTCLs, featuring advances in characterizing microscale distributions of Pt particles, ionomer, support particles and unraveling their interactions; advances in fundamental understandings of proton conduction and flooding behaviors in ionomer-free UTCLs; advances in modeling of conventional catalyst layers and especially UTCLs; and discussions on high-impact research topics in characterizing and modeling of catalyst layers.

https://rd.springer.com/content/pdf/10.1007%2Fs11708-017-0490-6.pdf

Review of characterization and modeling of polymer electrolyte fuel cell catalyst layer: The blessing and curse of ionomer

A fuel cell electrode catalyst, adapted for application to a carbon fiber support mat substrate to form a fuel cell electrode, comprising small crystals of noble metal fuel cell catalyst specie, such as platinum, deposited on discrete particles of an inert carrier or support such as carbon powder, is formed by the repetitive process of: mixing the powder with a dilute solution of the salt so as to form a slurry, the slurry then being concentrated and dried followed by the decomposition of the salt to form a partial product which is then used in place of the carrier powder in a repetition of the process until the desired concentration of catalyst is achieved. Usage of a low concentration of catalyst salt results in a smaller crystallite, which yields a higher surface area of catalyst, for a more active electrode that provides an improved current/voltage performance characteristic at a lower cost.

George Michael Anthony

Papers

Sequential catalyzation of fuel cell supported platinum catalyst