Abstract: A composite electrode includes two or more types of fibers forming a fiber network, comprising at least a first type of fibers and a second type of fibers. The first type of fibers comprises a first polymer and a first type of particles. The second type of fibers comprises a second polymer and a second type of particles. The second polymer is same as or different from the first polymer. The second type of particles are same as or different from the first type of particles.

Abstract: Nanofiber electrodes for electrochemical devices and fabricating methods of the same are disclosed. In one embodiment, the method includes forming a liquid mixture containing a catalyst, a first polymer of perfluoro sulfonic acid and a second polymer of polyethylene oxide, the first polymer of perfluoro sulfonic acid being pre-treated to remove protons in the first polymer by exchange with a cation species like Na+; and electro spinning the liquid mixture to generate electro spun fibers and deposit the generated fibers on a collector substrate to form a fiber electrode mat comprising a network of fibers, where each fiber has a plurality of particles of the catalyst distributed thereon.

Abstract: A bipolar membrane comprising a cation exchange mat of one or more cation exchange polymers, an anion exchange mat of one or more anion exchange polymers, and an internal 3D bipolar interface, disposed between the cation and anion exchange layers, including a mixture of at least one cation exchange polymer and at least one anion exchange polymer, such that an interface of the at least one cation exchange polymer and the at least one anion exchange polymer is the internal 3D bipolar interface that has a large area, and the at least one cation exchange polymer in the 3D bipolar interface is connected to the one or more cation exchange polymers of the cation exchange layer, and the at least one anion exchange polymer in the 3D bipolar interface is connected to the one or more anion exchange polymers of the anion exchange layer.

Abstract: Nanofiber electrodes for electrochemical devices and fabricating methods of the same are disclosed. In one embodiment, the method includes forming a liquid mixture containing a catalyst, a first polymer of perfluoro sulfonic acid and a second polymer of polyethylene oxide, the first polymer of perfluoro sulfonic acid being pre-treated to remove protons in the first polymer by exchange with a cation species like Na+; and electro spinning the liquid mixture to generate electro spun fibers and deposit the generated fibers on a collector substrate to form a fiber electrode mat comprising a network of fibers, where each fiber has a plurality of particles of the catalyst distributed thereon.

Abstract: A dual fiber mat for making an electrode includes first nanofibers and second nanofibers. The first fibers contain particles for electrochemical reaction and a binder. The second fibers contain particles for electron conduction and a binder. For a Li-ion battery anode, the first fibers include a polymer binder composed of an electron conducting polyfluorene derivative polymer (PFM or PEFM) or PVDF or PAA and silicon nanoparticles or silicon nanorods embedded in the binder. For a Li-ion battery cathode, the first fibers include a binder composed of an electron conducting polymer (PFM or PEFM) or PAA or PVDF and LiCoO2 or LiFePO4 or Li2MnO3 particles embedded in the binder. The second nanofibers include a PFM or PEFM binder or non-conductive polymer binder and electrically conductive nanoparticles embedded in the binder. The dual fiber mat has a thickness in a range of about 50-1000 ?m.

Abstract: An ink for forming nanofiber fuel cell electrodes, and methods of ink formulations, and membrane-electrode-assemblies for electrochemical devices. The ink includes a first amount of a catalyst, a second amount of an ionomer in a salt form, and a third amount of a carrier polymer dispersed in one or more solvents, where a weight ratio of the first amount to the second and third amounts is in a range of about 1-1.5, and a weight ratio of the second amount to the third amount is in a range of about 1-3. The ink has a solids concentration in a range of about 1-30 wt %. Preferably, the solids concentration is in a range of about 10-15%.

Abstract: A bipolar membrane comprising a cation exchange mat of one or more cation exchange polymers, an anion exchange mat of one or more anion exchange polymers, and an internal 3D bipolar interface, disposed between the cation and anion exchange layers, including a mixture of at least one cation exchange polymer and at least one anion exchange polymer, such that an interface of the at least one cation exchange polymer and the at least one anion exchange polymer is the internal 3D bipolar interface that has a large area, and the at least one cation exchange polymer in the 3D bipolar interface is connected to the one or more cation exchange polymers of the cation exchange layer, and the at least one anion exchange polymer in the 3D bipolar interface is connected to the one or more anion exchange polymers of the anion exchange layer.

Abstract: A method of fabricating a composite membrane, includes the steps of: forming a first solution comprising a charged polymer and a first uncharged polymer having a repeat unit of a formula of: where each of X and Y is a non-hydroxyl group; forming a second solution comprising a second uncharged polymer; electrospinning, separately and simultaneously, the first solution and the second solution to form a dual fiber mat; and processing the dual fiber mat to form the composite membrane.

Abstract: A method of forming a membrane-electrode-assembly (MEA) for an electrochemical device. The method includes providing a first solution formed by mixing a Pt/C catalyst, Nafion® and PVDF, and a second solution formed by mixing Pt/C catalyst, Nafion® and PPA; electrospinning respectively the first solution and the second solution to form a first nanofiber mat and a second nanofiber mat; pressing the first nanofiber mat and the second nanofiber mat on opposite sides of a polymer electrolyte membrane to form a catalyst coated membrane (CCM); and pressing a carbon gas diffusion layer on each of the cathode and the anode of the CCM to form the MEA.

Abstract: A method of forming an electrode for an electrochemical device includes mixing at least a first amount of a catalyst and a second amount of an ionomer or an uncharged polymer to form a liquid mixture; delivering the liquid mixture into a metallic needle having a needle tip; applying a voltage between the needle tip and a collector substrate positioned at a distance from the needle tip; and extruding the liquid mixture from the needle tip at a flow rate such as to generate electrospun fibers and deposit the generated fibers on the collector substrate to form a mat comprising a porous network of fibers, where each fiber has a plurality of particles of the catalyst distributed thereon.

Abstract: In one aspect, a method of forming an electrode for an electrochemical device is disclosed. In one embodiment, the method includes the steps of mixing at least a first amount of a catalyst and a second amount of an ionomer or uncharged polymer to form a solution and delivering the solution into a metallic needle having a needle tip. The method further includes the steps of applying a voltage between the needle tip and a collector substrate positioned at a distance from the needle tip, and extruding the solution from the needle tip at a flow rate such as to generate electrospun fibers and deposit the generated fibers on the collector substrate to form a mat with a porous network of fibers. Each fiber in the porous network of the mat has distributed particles of the catalyst. The method also includes the step of pressing the mat onto a membrane.

Abstract: In one aspect of the present invention, a method of fabricating a fuel cell membrane-electrode-assembly (MEA) having an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode electrode, includes fabricating each of the anode electrode, the cathode electrode, and the membrane separately by electrospinning; and placing the membrane between the anode electrode and the cathode electrode, and pressing then together to form the fuel cell MEA.

Abstract: In one aspect of the present invention, a fiber mat is provided. The fiber mat includes at least one type of fibers, which includes one or more polymers. The fiber mat may be a single fiber mat which includes one type of fibers, or may be a dual or multi fiber mat which includes multiple types of fibers. The fibers may further include particles of a catalyst. The fiber mat may be used to form an electrode or a membrane. In a further aspect, a fuel cell membrane-electrode-assembly has an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode electrode. Each of the anode electrode, the cathode electrode and the membrane may be formed with a fiber mat.

Abstract: A method of fabricating a composite membrane, includes the steps of: forming a first solution comprising a charged polymer and a first uncharged polymer having a repeat unit of a formula of: where each of X and Y is a non-hydroxyl group; forming a second solution comprising a second uncharged polymer; electrospinning, separately and simultaneously, the first solution and the second solution to form a dual fiber mat; and processing the dual fiber mat to form the composite membrane.

Abstract: A self-regulating gas generator that, in response to gas demand, supplies and automatically adjusts the amount of gas (e.g., hydrogen or oxygen) catalytically generated in a chemical supply chamber from an appropriate chemical supply, such as a chemical solution, gas dissolved in liquid, or mixture. In some embodiments, the gas generator may employ a piston, rotating rod, or other element(s) to expose the chemical supply to the catalyst in controlled amounts. In another embodiment, the self-regulating gas generator uses bang-bang control, with the element(s) exposing a catalyst, contained within the chemical supply chamber, to the chemical supply in ON and OFF states according to a self-adjusting duty cycle, thereby generating and outputting the gas in an orientation-independent manner. The gas generator may be used to provide gas for various gas consuming devices, such as a fuel cell, torch, or oxygen respiratory devices.

Abstract: In one aspect of the present invention, a method of fabricating a composite membrane includes: forming a first polymer solution from a first polymer and a second polymer solution from a second polymer, respectively, where the first polymer includes a charged polymer and the second polymer includes an uncharged polymer; electrospinning, separately and simultaneously, the first and second polymer solutions to form a dual fiber mat with first polymer fibers and second polymer fibers; and processing the dual fiber mat by softening and flowing one of the first or second polymer fibers to fill in the void space between the other of the first and second polymer fibers so as to form the composite membrane. In some embodiments, the composite membrane may be a proton exchange membrane (PEM) or an anion exchange membrane (AEM).

Abstract: In one aspect of the present invention, a method of fabricating a fuel cell membrane-electrode-assembly (MEA) having an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode electrode, includes fabricating each of the anode electrode, the cathode electrode, and the membrane separately by electrospinning; and placing the membrane between the anode electrode and the cathode electrode, and pressing then together to form the fuel cell MEA.

Abstract: In one aspect of the present invention, a fuel cell membrane-electrode-assembly (MEA) has an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode electrode. At least one of the anode electrode, the cathode electrode and the membrane is formed of electrospun nanofibers.

Abstract: In one aspect of the present invention, a method of fabricating a composite membrane includes: forming a first polymer solution from a first polymer and a second polymer solution from a second polymer, respectively, where the first polymer includes a charged polymer and the second polymer includes an uncharged polymer; electrospinning, separately and simultaneously, the first and second polymer solutions to form a dual fiber mat with first polymer fibers and second polymer fibers; and processing the dual fiber mat by softening and flowing one of the first or second polymer fibers to fill in the void space between the other of the first and second polymer fibers so as to form the composite membrane. In some embodiments, the composite membrane may be a proton exchange membrane (PEM) or an anion exchange membrane (AEM).

Abstract: A proton exchange membrane (PEM) with an ion exchange capacity of not less than 1 molar equivalent per kilogram and less than 20% water swelling is provided. The PEM includes a polymer having a polyphosphazene backbone with a polyaromatic functional group linked to the polyphosphazene as a polyaromatic side chain, a non-polyaromatic functional group linked to the polyphosphazene as a non-polyaromatic side chain, and an acidic functional group linked to the non-polyaromatic side chain. The polyaromatic functional group linked to the polyphosphazene provides for increased thermal and chemical stability, excellent ionic conductivities and low water swelling. The mole fraction of polyaromatic functional groups linked to the polyphosphazene backbone is between 0.05 and 0.60.