Patent Application
20070160896
This application claims the priority date of the U.S. provisional patent application Ser. No. XX/XXXX filed Dec. 3, 2005 entitled “Plasmonic Fuel Cell”, each of which is incorporated by reference herein in their entirety.
There is NO claim for federal support in research or development of this product.
This invention is related to improvements of fuel cell by nanotechnology effects and materials.
Since electrical production in fuel cells is highly efficient relative to other alternatives, they are seriously considered as realistic alternative, environmentally-sound energy sources.
In the last few years, enormous progress has been made in fuel cell technology. However, there are still many limitations and this progress does not resolve problems in fuel cell technology related to their low performance, such as those described below (but are not limited to them): low reactivity between the electrode/catalyst and the liquid or gas fuels, crossover of liquid and gaseous fuels through the ion conductive membrane-electrolyte, excessively high or low affinities of electrochemical reaction products to the electrode/catalyst and/or membrane-electrolyte, limitation to the use of fuels such as methanol and oxygen/air in the fuel cells over the more environmentally-friendly and cost-effective use of other fuels such as ethanol, alcohols of higher order, and peroxides, carbon monoxide formation in fuel cells, and corrosion of the fuel cell components.
To address these limitations, new breakthrough inventions are needed. The most successful inventions will be based upon the multi-disciplinary use of advances in numerous scientific and technology fields.
For example, in current fuel cell development, there is a need for different catalytic materials other than platinum that possess increased catalytic reactivity with fuels and costs less. However, there are physical and chemical limitations of the catalytic reactivity of many materials, and for these reasons, it is difficult to develop a material with a significantly higher catalytic reactivity than those currently utilized. One of the current approaches of enhancing the catalytic reactivity of materials in fuel cells is to make them smaller thus shrinking these materials to nanometer-sizes (nano-sizes). This approach takes advantage of an increased surface area of catalyst materials that is directly proportional to catalytic reactivity. However, there is a limitation of just how small particles can become and still remain useful in fuel cell technology. Additionally, this surface area versus catalytic reactivity effect is linear and will not lead to a breakthrough in catalyst technology. Therefore, new non-conventional approaches are needed in catalyst technology to enhance catalyst reactivity by several orders of magnitude. Similar breakthroughs are needed in electrode materials and membrane-electrolyte materials, such as ion conductive materials, electron conductive materials, and other doped materials. The outcome of these improvement efforts should dramatically shift the electrical output towards an almost completely efficient level in fuel cells.
Other breakthroughs are also needed in fuel cell technology in order to promote complete “burning” of fuels in fuel cells. There is a great need for the use of propane, ethanol, alcohols of higher order, and/or water (but are not limited to them) as fuels in fuel cells. Again, a new invention or several new combined inventions are needed to improve fuel cell technology.
The invention discloses novel solutions in fuel cell technology that are based upon advances in nanotechnology. The solutions relate to the use of an embedded plurality of nanostructures in a fuel cell, to the nanostructures micro- to nano-positions with respect to each other, to tuned nanostructure properties to energy sources and nanotechnology effects. Such proposed solutions lead to more effective electrochemical reactions, better generation/diffusion of ions, electrons, and reaction products at the reaction sites, to better “burning” of fuels, to reduced fuel cross-over effects, to more robust the fuel cell, to significantly increased production of electricity in the proposed fuel cells, and to other beneficial effects.
One of the embodiments of the invention describes the use of nanotechnology effects such as a surface plasmon resonance (SPR) enhancement and other nanotechnology enhancements. SPR in the nanostructures can provide an enormous enhancement of the nanostructure's reactivity to fuels. Such reactivity enhancement will produce more electricity in the fuel cells and will also promote better or complete “burning” processes, which leads to more efficient and safer fuel cells.
The invention considers the generation of SPR in the nanostructures by the electrochemical reactions occurring in fuel cells or by other internal and/or external energy sources. The electrochemical reactions are usually associated with the generation of electromagnetic radiation and heat that can be used for SPR generation and the other nanotechnology effects. The internal and/or external energy sources such as electromagnetic radiation, thermal, sonic, magnetic, electrochemical, and other energy sources can be powered by the fuel cell itself or by external sources.
In one of the embodiments of the invention it is proposed that SPR enhancement occurs at a reaction site where a luminescent probe is also located. The probe will enhance chemiluminescence produced by the electrochemical reactions by several orders of magnitude. The enhanced chemiluminescence will then be used to generate SPR in nanostructures that will increase their interaction with the fuel.
The invention also discloses fuel cells in which SPR and other nanotechnology effects are generated by the movement of fuel through the micro-/nano-porous/capillary structures of the electrodes. The interaction of fuels with such structures can be so intense as to even provide a separation of electrons and ions in water, which then can be used in the production of electricity in fuel cells. It is also proposed in the invention that an additional forcing of fuel movement through the structures will further enhance electrochemical reactions in the fuel cells due to better separation of fuel molecules and other effects.
Another embodiment of the invention discloses the use of the fuel enriched by the nanostructures. The enriching of fuels is particularly important for ethanol and higher order alcohols, but is not limited to them, where the “burning” processes of these fuels are not complete. The nanostructures in the fuel can have catalytic/ionic/electron properties activated at the reaction side in the electrodes, where SPR and other nanotechnology effects are present.
The invention also describes improvements in fuel cells related to crossover of the fuel through the membrane-electrolyte or excessive accumulation of the reaction products at the membrane-electrolyte site and the electrode sites. It is proposed to utilize the induced hydrophobicity and/or hydrophilicity of the embedded plurality of the nanostructures to mitigate these problems.
a, 5b, and 5c show the carbon nanotubes with other attached nanostructures to inner walls or to external walls, or to both the internal and external walls, respectively.
a and 7b show capillaries built into the electrode based upon the random and fixed (composite) distributions of nanostructures, respectively.
1. Abbreviations.
The invention discloses novel solutions in fuel cell technology that are based upon advances in nanotechnology. The solutions relate to the use of an embedded plurality of nanostructures in a fuel cell, to the nanostructures micro- to nano-positions with respect to each other, to tuned nanostructure properties to energy sources and nanotechnology effects. Such proposed solutions lead to more effective electrochemical reactions, to better generation/diffusion of ions, electrons, and reaction products at the reaction sites, to better “burning” of fuels, to reduced fuel cross-over effects, to more robust the fuel cell, to significant increased production of electricity in the proposed fuel cells, and to other beneficial effects.
The invention considers the use of the embedded plurality of nanostructures of different sizes, shapes, and materials that have relevant impact on their properties and functions in the fuel cell. Therefore, the nanostructures in the proposed fuel cell are especially designed to provide enhanced interactions with a fuel and fuel products in addition to the other interactions with energy sources originating within the fuel cell or powered externally.
Materials for the nanostructures are selected from the group of materials: noble metals, non-noble metals, metal alloys, metal oxides, combinations of metal alloys with metal oxides, non-metallic electron conductive materials, non-metallic semiconductive materials, ion conductive materials, carbon nanotubes, silicates, chemical substances, luminescent probes, but are not limited to them.
The proposed arrangements of the embedded plurality of nanostructures in an electrode 104 are shown in
The embedded nanostructures may have a function or multiple functions in the fuel cells such as (but are not limited to them): hydrogen storage, fuel delivery, hydrophilicity, hydrophobicity, electron conductor, catalyst, ion conductor, luminescent, luminescence enhancer, plasmon generation enhancer, electro-hole pairs generation enhancer. It is proposed that the function or multiple functions of the nanostructures are stimulated or controlled by the energy sources originating within the fuel cell and/or powered externally.
One of the embodiments discloses the use of carbon nanotubes 107 for delivering fuels to an anode electrode 104 and cathode electrode 105, as it is shown in
One of the embodiments of the invention proposes methods of changing nanostructure-fuel reactivity and other nanostructure properties by the presence of other nanostructures, for the purposes of enhancing the performance of the fuel cell. As is show in Figures 5a, 5b, and 5c, the nanostructure (for example, the carbon nanotube 107) has another nanostructure attached, the catalyst 101, to the inner walls or to the external walls, or to both the internal and external walls, respectively. Each configuration of attachments may induce different properties of the carbon nanotube including accelerated fuel movement, increased nanostructure-fuel reactivity, and enhanced storage capabilities of hydrogen or hydrocarbons, but are not limited to them.
One of the designs of this invention also calls for embedding carbon nanotubes 107 into the electrodes (
Another embodiment of the invention is related to fuel cells in which there are embedded “nanometer range”-sized nanostructures. It is well known that such small-sized nanostructures have a total reaction surface area larger than the larger-sized structures. Thus, for equivalent weights of nanostructures, the “nanometer range”-sized nanostructures lead to higher reactivity with fuel. This effect allows a reduction in the amount of certain materials used in fuel cells, which is particularly important for fuel cells using expensive materials such as platinum. However, there exists a limit to how small materials can become and still remain useful in fuel cells.
Therefore, the invention proposes further improvements to fuel-nanostructure reactivity by utilizing in the proposed fuel cell nanotechnology effects such as surface plasmon resonance (SPR), electron-hole pair effects, and luminescence effects, but are not limited to them. The proposed effects increase fuel-nanostructure reactivity by several orders of magnitude and the previously mentioned surface area effect of shrinking the nanostructures to their physical limits to enhance reactivity with fuel will be less important. In order to take advantages of these effects in fuel cells, the nanostructures must be properly selected and especially designed. For example, nanostructures with sharp edges can generate with the internal and external energy sources SPR electromagnetic fields up to 10 microns from the nanostructures, and fuel within 10 microns from these nanostructures is greatly affected by the SPR electromagnetic fields leading to easier chemical breakdown and to the production of more electrons and ions.
The invention discloses a fuel cell in which the SPR electromagnetic fields in the nanostructures are induced by internal and/or external energy sources, and the nanostructure properties are designed to enhance the SPR interactions and other nanotechnology effects with the applied energy sources. For example, to effectively generate SPR electromagnetic fields in silver nanostructures or in gold nanostructures using light, silver nanostructures or gold nanostructures must be illuminated by blue or red light, respectively.
The invention also anticipates the use of nanostructures with a plurality of sizes in the proposed fuel cell. Nanostructures measuring one nanometer have different properties than those measuring 10-20 or 100 nanometers, even if they are made from the same material. Therefore, the proposed use of a plurality of sizes takes advantage of these nanotechnology effects. For example, the one nanometer-sized nanostructures may enhance SPR generation in the 10-20 nanometer-sized nanostructures by absorbing energy from electrochemical reactions and then emitting light which will be reabsorbed by the 10-20 nanometer-sized nanostructures. Another example describes a design of a fuel cell with a plurality of nanostructures in which some of the nanostructures are one nanometer carbon nanotubes.
The fuel flowing through or near the carbon nanotubes will generate not only electrons and ions, but also will induce electron-hole pairs in carbon nanotubes, which during recombination will produce luminescence. This luminescence can be used to generate SPR in the other nanostructures for the purpose of enhancing efficiency of the fuel cell. The luminescent wavelengths of carbon nanotubes can be tuned by their size to maximize fuel cell efficiency. Such a method can also be extended to other nanostructures and it is contemplated as a part of the invention.
The invention also considers SPR generation in the nanostructures by the electrochemical reactions occurring within the fuel cell or by other internal and/or external energy sources. The electrochemical reactions are associated with the generation of electromagnetic radiation and heat that can be used for SPR generation and other nanotechnology effects. The internal and/or external energy sources for SPR generation such as electromagnetic radiation, thermal, sonic, magnetic, and other energy sources can be powered by the fuel cell itself or by external sources, and are considered as a part of the invention.
One of the embodiments of the invention proposes SPR generation at a reaction site where a luminescent probe 108 is also located (
The invention also discloses fuel cells in which SPR and nanotechnology effects are generated by the movement of fuel through the micro-/nano-porous/capillary structures of the electrodes. The interaction of fuels with such structures can be so intense as to even provide a separation of electrons and ions in water, which then can be used in the production of electricity in fuel cells. It is also proposed in the invention that an additional forcing of fuel movement through the structures by internal and/or external energy sources will further enhance electrochemical reactions in the fuel cells.
Another embodiment of the invention discloses the use the fuel enriched by the nanostructures. The enriching of fuels is particularly important for ethanol and higher order alcohols, but is not limited to them, where the “burning” processes of these fuels are usually incomplete. The colloidal nanostructures enriching the fuels can have catalytic/ionic/electron and other properties activated at the reaction side in the electrodes, where SPR and other nanotechnology effects are present.
The invention also describes improvements in the fuel cell related to fuel crossover through the membrane-electrolyte or related to excessive accumulation of the reaction products at a membrane-electrolyte site and the electrode sites. It is proposed to utilize the induced hydrophobicity and/or hydrophilicity by the nanostructures to mitigate these problems. One of the improvements of the fuel cell is shown in
Although the invention has been explained in relation to its preferred embodiment as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.
