Ballard Power Systems Corporation

Bdf IP Holdings Ltd.

Charles Stone

Alfred E Steck

Jinzhu Wei

Robert D Lousenberg

Timothy J Peckham

Jianfu Ding

Steven Holdcroft

Donald J Burton

Carmen Chuy

Sean M MacKinnon

David Alexander Summers

Biswajit Choudhury

Anilkumar Raghavanpillai

Dave Summers

Anne E Morrison

A water insoluble additive for improving the performance of an ion-exchange membrane, such as in the context of the high temperature operation of electrochemical fuel cells. The insoluble additive comprises a metal oxide cross-linked matrix having acid groups covalently attached to the matrix through linkers. In one embodiment, the metal is silicon and the cross-linked matrix is a siloxane cross-linked matrix containing silicon atoms cross-linked by multiple disiloxy bonds and having  acid groups covalently attached to the silicon atoms through alkanediyl linkers.

Water insoluble additive for improving conductivity of an ion exchange membrane

Ion-exchange materials comprising a polymeric backbone and a plurality of pendent styrenic or fluoridated styrenic macromonomers covalently bonded thereto, wherein the plurality of pendent styrenic or fluorinated styrenic macromonomers comprise a uniform number of styrenic or fluoridated styrenic monomer repeat units, and wherein predominantly all of the styrenic or fluoridated styrenic monomer repeat units have at least one charged group. Processes for making such material, as well as products related thereto, are also disclosed. In a representative embodiment, the ion-exchange material is utilized as a proton-exchange membrane (PEM) for use in a PEM fuel cell.

Ion-exchange materials with improved ion conductivity

Graft polymeric membranes and methods for making graft polymeric membranes have one or more trifluorovinyl aromatic monomers that are radiation graft polymerized to a polymeric base film. The membranes comprise a polymeric base film to which has been graft polymerized substituted &agr;,&agr;,&bgr;-trifluorostyrene and/or &agr;,&agr;,&bgr;-trifluorovinylnaphthylene monomers, which are activated towards graft polymerization. As ion-exchange membranes, the membranes are suitable for use in electrode apparatus, including membrane electrode assemblies in, for example, fuel cells. The membranes can also be crosslinked.

Graft polymeric membranes and ion-exchange membranes formed therefrom

A composite membrane for use in a fuel cell membrane electrode assembly comprises a porous polymeric substrate and an impregnant partially filling the substrate such that the substrate comprises a first region having pores substantially filled with the impregnant, and a second substantially porous region. The impregnant comprises a cation exchange material. The cation exchange material covers one surface of the substrate in a dense surface layer, contiguous with the first region of the substrate. The substrate has greater than 10% residual porosity, and the composite membrane is substantially gas impermeable and has at least one substantially porous major surface.

Composite ion exchange membrane for use in a fuel cell

&agr;,&bgr;,&bgr;-Trifluorostyrene and derivatives thereof synthesized in two steps from 1,1,1,2-tetrafluoroethylene. In the first step, 1,1,1,2-tetrafluoroethylene is reacted with a base, a metal salt such as zinc chloride and an optionally amine to form a trifluorovinyl metal complex. In the second step, the trifluorostyrene or derivative is obtained by reacting the trifluorovinyl metal complex with an aryl transfer agent such as, for example, an aryl triflate or an aryl halide, in the presence of a metal catalyst and optionally a coordinating ligand. Both steps may be carried out in one reactor.

Synthesis of &agr;, &bgr;, &bgr;-trifluorostyrene via in-situ formation of trifluorovinyl metal halide

Stripped porous polymer film and a method for making such film from substantially heterogeneous porous polymer film are described. The heterogeneous film has surface characteristics that are different from the characteristics of the interior bulk material, and the method comprises mechanically stripping at least a portion of at least one surface layer from the heterogeneous film. The stripped porous polymer film may be incorporated into composite membranes. Such composite membranes are particularly suitable for incorporation into membrane electrode assemblies for use in electrochemical cells, including electrochemical fuel cells.

Method of making stripped porous polymer films

A composite membrane is provided in which a porous substrate is impregnated with a polymeric composition comprising various combinations of &agr;,&bgr;,&bgr;-trifluorostyrene, substituted &agr;,&bgr;,&bgr;-trifluorostyrene and ethylene-based monomeric units. Where the polymeric composition includes ion-exchange moieties, the resultant composite membranes are useful in electrochemical applications, particularly as membrane electrolytes in electrochemical fuel cells.

&agr;,&bgr;, &bgr;-trifluorostyrene-based composite membranes

Graft polymeric membranes in which one or more trifluorovinyl aromatic monomers are radiation graft polymerized to a preformed polymeric base film are provided, as well as ion-exchange membranes prepared therefrom. Preferred monomers include substituted &agr;, &bgr;, &bgr;-trifluorostyrenes and trifluorovinyl naphthalenes which are activated towards the grafting reaction or facilitate the introduction of more than one ion-exchange group per monomer unit in the grafted chains. The ion-exchange membranes are useful in dialysis applications, and particularly in electrochemical applications, for example as membrane electrolytes in electrochemical fuel cells and electrolyzers.

A composite membrane is provided in which a porous substrate is impregnated with a polymeric composition comprising various combinations of &agr;, &bgr;, &bgr;-trifluorostyrene, substituted &agr;, &bgr;, &bgr;-trifluorostyrene and ethylene-based monomeric units. Where the polymeric composition includes ion-exchange moieties, the resultant composite membranes are useful in electrochemical applications, particularly as membrane electrolytes in electrochemical fuel cells.

&agr;,&bgr;,&bgr;-trifluorostyrene-based composite membranes

A composite membrane is provided in which a porous substrate is impregnated with a polymeric composition comprising various combinations of .alpha.,.beta.,.beta.-trifluorostyrene, substituted .alpha.,.beta.,.beta.-trifluorostyrene and ethylene-based monomeric units. Where the polymeric composition includes ion-exchange moieties, the resultant composite membranes are useful in electrochemical applications, particularly as membrane electrolytes in electrochemical fuel cells.

.alpha., .beta., .beta.-trifluorostyrene-based composite membranes

Substituted .alpha.,.beta.,.beta.-trifluorostyrene-based composite

Polymeric compositions are derived from copolymers of .alpha.,.beta.,.beta.-trifluorostyrene with a variety of substituted .alpha.,.beta.,.beta.-trifluorostyrenes. These compositions are suitable for use as membranes, particularly as ion-exchange membranes, and most particularly as solid polymer electrolytes in electrochemical applications, such as, for example, electrochemical fuel cells.

Trifluorostyrene and substituted trifluorostyrene copolymeric

Sulfonyl fluoride substituted .alpha.,.beta.,.beta.-trifluorostyrene monomers are disclosed. The monomers are incorporated into polymeric compositions which are conveniently hydrolyzed to produce polymeric compositions which include ion-exchange moieties. The resulting compositions which include ion-exchange moieties are particularly suitable for use as solid polymer electrolytes in electrochemical applications, such as, for example, electrochemical fuel cells.

Substituted trifluorostyrene monomeric compositions

Substituted trifluorostyrene compositions

Polymeric compositions are derived from copolymers of .alpha.,.beta., .beta.-trifluorostyrene with a variety of substituted .alpha.,.beta.,.beta.-trifluorostyrenes. These compositions are suitable for use as membranes, particularly as ion-exchange membranes, and most particularly as solid polymer electrolytes in electrochemical applications, such as, for example, electrochemical fuel cells.

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Vancouver, Canada

Charles Stone