Battery Resistance Reduction and Battery Materials

Abstract

To provide a battery with reduced resistance.SOLUTION: The electrical resistance of an active cathode and anode membranes can be significantly reduced by the addition of small amounts of conductive additives in a battery system. The reduction in resistance at the cathode and / or anode results in easier transport of electrons through the battery and increase in power, capacity, and speed while reducing Joule heating losses.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] Related Applications This application is an international PCT application titled "Resistance Reduction in Battery and Battery Materials", claiming the benefit of U.S. Provisional Application No. 63 / 038,864, titled "Resistance Reduction in Battery Materials", filed on June 14, 2020, and U.S. Patent Application No. 17 / 340,063, titled "Resistance Reduction in Battery and Battery Materials", filed on June 6, 2021, each of which is incorporated herein by reference.

Background Art

[0002] Background of the Invention 1. Technical Field of the Invention The present invention relates to improving battery performance by increasing the conductivity of the cathode and anode of a battery. More specifically, the present invention relates to a method and system for improving battery performance by reducing the electrical resistance in both the in-plane direction, and particularly the thickness direction, of the active film, thus increasing the conductivity, increasing the charge and discharge rate, and ultimately increasing both the power and energy density.

[0003] Various exemplary embodiments of the present invention are described below. The use of the term "exemplary" means being illustrative or merely by way of example, and any reference to "the invention" in this disclosure is not intended to limit or confine the invention to any one or more exact features or steps of the exemplary embodiments disclosed herein. References to "exemplary embodiments", "one embodiment", "an embodiment", "some embodiments", "various embodiments", etc. can indicate that one or more embodiments of the invention so described may include a particular structure, feature, property, or characteristic, but not all embodiments necessarily include the particular structure, feature, property, or characteristic. Further, repeated use of the phrases "in one embodiment" or "in an exemplary embodiment" may refer to the same embodiment, but not necessarily so.

[0004] 2. Related Art Among many other technologies, a preferred method for storing electrical energy is a battery. Briefly, a battery is a device in which an anode (negatively charged, or reducing electrode) can be filled with electrons by an electrochemical galvanic process, and a cathode (positively charged, or oxidizing electrode) where the electrochemical galvanic reaction is reversed and the stored electrons are released into a circuit to provide current in that way. Batteries in which these reactions are not reversible singly are called primary batteries, and these cannot be recharged. Batteries in which these reactions can be reversed multiple times are called secondary batteries or rechargeable. The examples described in this disclosure are inherently secondary, but those skilled in the art will understand that the concepts described in this disclosure are applicable to both primary and secondary systems.

[0005] The design of a battery and the selection of materials are a function of the galvanic potential between the materials and their ability to provide a potential designed to drive current through a circuit to supply power.

[0006] An important part of battery design is the way to collect and distribute current. The examples described in this disclosure are applicable to lithium-ion rechargeable batteries, but the concepts disclosed in this disclosure (methods and materials for significantly improving current collection) apply to all batteries because all batteries generally use current collectors. For the purposes of this disclosure, all battery systems containing lithium are identified as lithium-ion batteries. The selection of materials used to improve current collection by the methods described in this disclosure needs to be compatible with the electrochemical galvanic reaction of the battery so that the selected materials do not become active corrosion products of the battery.

[0007] For the purposes of this disclosure, the exemplary embodiments described in this disclosure include lithium-ion secondary batteries, specifically cathodes of lithium iron phosphate or lithium nickel manganese cobalt oxide and carbon powder anodes. However, those skilled in the art will understand that the concepts taught in this disclosure can be applied to any battery for which the materials, methods, and techniques described provide the improvements described.

[0008] There are many factors that affect battery performance, such as ion transport through both the anode and cathode and across the separator barrier, chemical kinetics, and SEI (solid electrolyte interphase) formation. The main factor is the ability to transport electrons through a system that is many series resistors; starting from the anode current collector foil, through the anode foil / active material interface, from the anode active material to the electrolyte (where lithium accepts electrons at the anode during charging), transporting that electron and lithium across the barrier to the cathode, separating the electron from lithium at the cathode, passing through the cathode active material, then transporting the electron to the active material / foil interface, and then moving the electron out of the foil to the device in which it functions.

[0009] In the lithium-ion battery system considered by way of example of the present disclosure, current collection at the anode is inherently promoted. This is because the carbon powder used to capture and store lithium ions during the charging cycle is already moderately conductive. Its conductivity is often further improved by the addition of finely divided carbon powder. Nevertheless, the anode film must be thin (e.g., 50 to 100 microns thick) and must be applied to a current collector of copper or nickel foil. Furthermore, its intrinsic volume resistivity, in part, limits the rate at which it can be charged by the ability to conduct current through both the active material and both the carbon / foil interface and the polymer binder (another limiting factor is the ability to transport, accept, and store lithium ions). The relationship between voltage, current, and resistance is defined by Ohm's law. When the conductivity of the anode is higher, the electrical resistance decreases, so the applied voltage required to pass a given current decreases, or conversely, a higher current flows at a given voltage. This reduction in resistance further results in a reduction in resistive heating losses. Also, as the conductivity increases, it becomes possible to use a thicker anode film, and thus the capacity increases.

[0010] However, current collection at the cathode is a different matter because many cathode active materials are either insulators or poor conductors. In the exemplary embodiments described in the present disclosure, lithium iron phosphate (hereinafter, LFP) and lithium nickel manganese cobalt oxide (hereinafter, NMC) are non-conductive insulators. Typically, however, these materials are combined with a small amount of polymer binder and conductive submicron carbon and then thinly spread over an aluminum foil substrate. For a given battery design, the cathode film is approximately twice the thickness of the anode film. To provide an appropriate level of conductivity in the thickness direction of the non-conductive LFP or NMC, a few percent of moderately conductive, finely divided carbon powder (such as named Super P) is added to the mixture. Looking at this more globally, the volume resistivity of the cathode film is about one to two orders of magnitude smaller than that of the anode.

[0011] This large difference in conductivity results in cathode resistance, which is the most extreme limiting factor for the discharge rate or capacity of the battery. For example, to obtain a higher discharge rate (power cell), the cathode needs to be made thinner so that electrons are closer to the current collector foil. However, the thinner the film, the lower the capacity of the battery. Conversely, the capacity of the battery can be increased by increasing the thickness of the cathode film, but in this case, the discharge rate decreases correspondingly. Therefore, it is possible to design for power or for capacity, but not for both. If the conductivity of the cathode can be significantly improved, a significant increase in capacity or power, or a combination of both, can be achieved.

[0012] The same design concept also applies to the trade-off between anode thickness, capacity, and speed. Furthermore, any means of increasing the conductivity of the anode or cathode reduces resistance or impedance across the entire battery system, increases voltage or amperage, and further increases either speed or capacity or both. The increase in conductivity also results in a reduction in Joule heating. The reduction in Joule heating is a very important factor for two reasons. First, due to the reduction in Joule heating, this energy appears in a larger capacity. Second, by reducing heating, a safer battery at a lower temperature is provided.

[0013] Despite many recent advances in the battery industry in the ability to transport, store, and chemically exchange lithium and its ions and electrons, as well as advances in cathode and anode chemistries, the industry has not seen any significant advances in the electrical conductivity of anode or cathode films for decades.

[0014] Therefore, there is a need for more efficient electrodes, i.e., electrodes that significantly improve efficiency, discharge time, recharge rate, power density, and energy density without sacrificing mass or size. Such electrodes are disclosed in the present disclosure. SUMMARY OF THE INVENTION

[0015] SUMMARY OF THE INVENTION The present disclosure addresses developments in the art, particularly addressing problems and needs in the art that are not yet fully solved by currently available electrodes. The electrodes of the present disclosure are easily implemented and provide significant improvements in both power density and energy density. Exemplary electrodes can be used in batteries of all sizes and masses, from use in small electronic devices such as cell phones and laptop computers, to electric vehicles such as golf carts and automobiles, for example, to very large scale centralized batteries for renewable energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Brief Description of the Drawings Exemplary embodiments of the present invention are described more fully hereinafter with reference to the accompanying drawings in which multiple exemplary embodiments of the present invention are shown. Like numbers used in the present disclosure refer to like elements throughout. However, the invention can be embodied in various forms and should not be construed as limited to the embodiments set forth in the present disclosure; rather, these embodiments are provided so that this disclosure will be thorough and complete. Accordingly, the disclosed configurations are merely exemplary and do not limit the scope of the invention, and the full scope of the appended claims and all of their equivalents should be given. Further, many embodiments such as adaptations, variations, modifications, and equivalent configurations are implicitly disclosed by the embodiments set forth in the present disclosure and fall within the scope of the present invention.

[0017] Although certain terms are used in this disclosure, they are used only in a general and descriptive sense and not for purposes of limitation. Unless specifically defined otherwise in this disclosure, such terms are intended to have their broad, ordinary and customary meaning as would be applicable in the relevant industry without conflict and without being limited to any particular embodiment described hereinafter. As used in this disclosure, the article "a" is intended to include one or more elements. Where only one element is intended, the term "one", "single", or similar words are used. When used in this disclosure to join lists of elements, the term "or" indicates at least one of the elements, but does not exclude more than one of the elements of the list. Additionally, unless otherwise clearly indicated from the context of the description, the terms "operator", "user", and "individual" can be used interchangeably in this disclosure.

[0018] The drawings are schematic views of various components and embodiments and are not drawn to scale. In this case, schematic views are used to assist in the understanding of the relative relationships between components. It is understood that these drawings represent only typical exemplary embodiments of the present invention and should not be considered as limiting its scope. The present invention is described and explained with additional specificity and detail with reference to the accompanying drawings:

Figure 1

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Figure 5

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Figure 7

Figure 8

[0019] Improving the conductivity in both the anode and cathode is desirable and beneficial. A greater advantage is derived from the ability to improve the conductivity of the cathode. The anode is moderately conductive, typically having a volume resistivity of about 0.1 ohm-cm; while the volume resistivity of the cathode is about 1 - 10 ohm-cm. Due to the low conductivity of the cathode film, the discharge energy capacity of the battery is limited by the inability of the cathode film to conduct electrons through its thickness to the aluminum foil current collector. Conversely, when more power is desired, the film needs to be made thinner to facilitate faster electron transport to the foil, thus sacrificing capacity. Considering a certain thickness, the higher the conductivity of the cathode film, the faster the discharge rate. Instead, a film with a lower resistivity can be placed thicker at the same resistance, resulting in an increased capacity at the same output rate. Therefore, the energy density can be increased approximately by the ratio of the thicknesses.

[0020] A significant improvement in the conductivity of either the anode or the cathode results in a lower resistivity not only in the in-plane or thickness direction of each of the anode or cathode films, but also generally across the entire battery cell. As a result, the lower the resistance, the higher the voltage required to move a given current, or the higher the current that can be moved at a given voltage. This, in turn, results in either faster charge and discharge or the ability to move electrons more easily through a thicker film, and thus an increase in capacity. Joule heating is also reduced, corresponding to a reduction in temperature and energy loss. The reduction in operating temperature also leads to a more efficient and safer battery.

[0021] This disclosure describes various exemplary methods that can improve the electrical conductivity of the cathode and / or anode. The magnitude of the improvement may be by a fractional margin (such as 25% or 50%, etc.) or by an integer margin such as two-fold, three-fold, or greater. This disclosure further describes improvements in the operation of a completed lithium-ion cell.

[0022] Furthermore, described in this disclosure are exemplary conductive additives for the anode and cathode, as well as their respective effects on the performance of these components. Additionally, battery cells made from these materials are described. Although optimal performance has not yet been achieved, this disclosure clearly demonstrates the effectiveness of these exemplary materials.

[0023] Furthermore, there may be evidence suggesting that morphological changes resulting from adding some of these exemplary materials may facilitate ion transport. It is also proposed that the non-carbon surface of a highly conductive anode additive may inhibit SEI growth. However, at present, both of these ideas are hypothesized and not claimed or exemplified in this disclosure.

[0024] Conductive Additive The following exemplary materials were evaluated for increased conductive performance. It should be understood that the present disclosure is not limited to these exemplary materials and methods. Those skilled in the art, upon understanding the disclosure herein, will understand that the described exemplary materials exemplify a broader concept.

[0025] Metal-coated fibers The addition of metal-coated fibers to either the anode or the cathode improves the conductivity in both membranes. The metal can be any metal and the fiber can be any fiber as long as the chemical, physical, and mechanical properties of the fiber and the metal coating are compatible with each other and with the respective properties of the selected anode or cathode. Minimizing the fiber diameter, maximizing the length, optimizing the length-to-dispersibility-to-effective concentration, minimizing the density, and maximizing the conductivity of the fiber are just some of the highly interrelated properties to be considered.

[0026] Metal-coated fibers have been commercial items for decades. Many metals (to name a few, nickel, silver, aluminum, gold, iron, copper, chromium, cobalt, molybdenum) have been deposited onto various fibers (to name a few, carbon, surface-modified carbon, silicon carbide, silicate, borosilicate, alumina, basalt, quartz, aramid, acrylic, rayon, nylon, cotton, silk). Smaller fiber diameters are more preferred because this increases the available length and specific surface area of the fiber per given unit mass, and the conductive surface area per unit mass available for electron interconnectivity.

[0027] Deposition processes for coating the fibers include vacuum processes (PVD, sputtering, evaporation, etc.), wet chemical processes (electroplating, electroless plating), and chemical vapor deposition (CVD). The general conductivity concept taught in the present disclosure is somewhat constrained by the deposition method, although some of these methods provide better coating uniformity and control.

[0028] Other parameters are important. For example, the selection of the fiber (substrate) and the selection of the metal (coating) need to be compatible with the chemistry of the battery system. The galvanic corrosion potential of the metal coating with respect to the selected ion electrolyte must be greater than the operating voltage of the battery, because if this is relatively low, as will be discussed below with respect to Example 1, it will undergo galvanic corrosion prematurely. In addition, the volume resistivity of the coated fiber needs to be smaller than that of the active film. The wider this improvement, the greater the increase in performance. The length of the fiber is also important. The fiber can be cut to a very precise and consistent length in the range of 0.1 mm to 1.0 mm. In addition, the fiber can also be precisely cut to a conventional length of several millimeters.

[0029] The work on dispersion shows that precise consistency in fiber length significantly reduces the amount of fiber required for the desired conductivity, thereby reducing viscosity and dispersion problems. However, at concentrations high enough to achieve the desired conductivity, fibers longer than 1 mm may entangle and not disperse well. At the other extreme of the length range, fibers 0.1 mm in length disperse very well, but due to their shorter aspect ratio, more of them are required for the desired conductivity. This filling with additional material increases mass and cost, but more importantly, this replaces the active battery material, thereby correspondingly reducing the available capacity.

[0030] The use of fibers of 0.5 mm or about 0.5 mm is particularly suitable for dispersion, and the length can be adjusted upward or downward from 0.5 mm depending on other factors such as diameter or to facilitate dispersion. Fibers produced by any known means can have their length changed within the range of 0.1 mm to 1 mm described above, but it is preferred to use precision-cut fibers, where precision-cut fibers mean that the fibers are uniform within ±10% of the selected length (e.g., for 0.5 mm fibers, all fibers are between 0.45 and 0.55 mm). At that length, the fibers can be dispersed in the active anode and cathode materials up to about 10 mass%. However, in practice, it is difficult to achieve a dispersion exceeding 5%, and a dispersion exceeding about 2% - 3% does not contribute to the conductivity commensurate with their additional mass, cost, or replacement of the active material.

[0031] Various examples of metal-coated fiber additives candidates are shown below, along with an explanation of their relative effectiveness as additives:

[0032] Carbon fibers Continuous woven fabrics, felts, or chopped forms of carbon fibers have been the subject of extensive battery research as current collectors, support members, or mechanical reinforcements. However, these fibers do not exhibit sufficient conductivity to achieve the desired objectives of the present disclosure.

[0033] Nickel-coated carbon fibers Nickel-coated carbon fibers are commercial items. The combination of their small diameter, low density, high aspect ratio, high linear mass yield, excellent electrical conductivity, and environmental stability provides an excellent conductive network in a very small amount. However, the corrosion of nickel with respect to lithium occurs at 3.75 volts, and since lithium NMC cathodes operate at 4.2 volts, the nickel on the fibers corrodes at 3.75 volts, and thus the manufactured battery does not cycle and fails at 3.75 volts. However, in lithium iron phosphate (LFP) batteries, the maximum voltage is 3.6V and the operating voltage is around 3.2V. Therefore (as shown in the example), nickel-coated fibers operate well. For the NMC system, a metal that can withstand more than 3.75V against lithium is required for operation up to 4.2V. Fortunately, aluminum against lithium reacts at 4.7V. Thus, in the example, it is shown that aluminum-coated fibers form this LFP system. This lesson is that the potential voltage of the conductive metal compared to the electrolyte ions must be higher than the operating voltage of the element, whether it is a cathode or an anode. Therefore, nickel-coated fibers are expected to work well with lithium-ion anodes but not with lithium-ion cathodes. In such cases, it is shown in some of the following examples. When the operating voltage of the cathode is low enough, the use of the nickel materials described in the present disclosure is an effective way to reduce resistivity.

[0034] Aluminum-coated fibers The use of aluminum-coated fibers in lithium-ion batteries is a good choice because the lithium / aluminum reaction occurs at 4.7 volts and does not reach the corrosion reaction up to 4.7 volts. With the use of a lithium NMC cathode operating at 4.2 volts, there is no corrosion reaction. As evidence, the current collector in a lithium-ion battery is made of aluminum foil.

[0035] A number of types of aluminum-coated fibers can be contemplated. Aluminum is typically coated onto fibers and fabrics through a vacuum process or a melting process. The uses of these products are usually essentially optical, such as reflectors (optical fibers or mylar balloons) or heat reflectors (gloves for high-temperature processes). These have been commercial items for decades. However, these fibers are large in diameter (usually over 25 microns) and have a density of about 2.7 g / cc. They could be viable candidates, but their large diameter and moderate density result in a linear yield that is hard to call desirable.

[0036] Aluminum-coated carbon fibers Aluminum-coated carbon fibers are not a viable option because aluminum carbide is easily formed.

[0037] Aluminum coating on nickel coating on carbon fiber When a barrier such as a nickel film or coating is placed between carbon and aluminum, aluminum can be deposited as a thin film on the nickel. This is shown in the following success example. However, after about a one-week cycle, the nickel begins to react with lithium and the battery fails.

[0038] Aluminum coating on other fibers Any fiber that does not form carbides during or after deposition, or at least whose surface is already carbide, is a candidate for aluminum deposition. The aluminum deposition is deposited by chemical vapor deposition from any aluminum-containing organometallic compound. Examples of proven aluminum-coated fibers include fibers such as silicon carbide, silicate, alumina, aluminum borosilicate, basalt, quartz, aramid, etc. Each of these fibers has been demonstrated to readily accept a thin aluminum film, but this list is by no means exhaustive. Thus, the fibers (substrates) of aluminum-coated fibers can be selected from the group including carbon, pan ox (oxidized PAN), silica, quartz, silicate, alumina, aluminosilicate, borosilicate, glass, mineral, carbide, nitride, boride, polymer, cellulose, inorganic fiber, and organic fiber.

[0039] Surface Modification of Carbon Fibers The surface of carbon fibers can be modified to silicon carbide, and then aluminum can easily coat the silicon carbide surface. This fiber provides the approach with the smallest diameter and the lowest density.

[0040] Other Metal-Coated Fibers Such metal-coated fibers have been demonstrated to be useful, such as copper-coated carbon fibers.

[0041] Powder and Filamentous Branched Metals When nickel is actively used due to its conductivity, such as in a lithium-ion anode or an LFP cathode, certain nickel powders may function to further provide an electrical path between metal-coated fibers or may function to provide multiple conduction paths through the active material / polymer / foil current collector interface. The synergistic effect of adding other conductive solid shapes, such as small plates or spheres, is known to increase the interconnectivity between metal-coated fibers. In one particularly advantageous method, nickel powder having a highly filamentous and branched structure where the main branches of the structure generally exceed 1 micron in diameter and are somewhat branched (e.g., Inco type 255 powder) can be used. The filamentous branched metal known as "nanostrand" typically has branches with a diameter of less than 1 micron and exhibits a very extensive branching (the "nanostrand" is available from the Conductive Composites Company of Heber City, Utah).

[0042] By using a combination of additives such as metal-coated fibers and filamentous branched structures such as branched nickel powder or nanostrand, the metal-coated fibers and the conductive filamentous structures with a high aspect ratio work together to construct an inclusive network of electron transport paths. The physical properties of the metal-coated fibers and one or more conductive filamentous structures with a high aspect ratio facilitate the construction of an inter-fiber electron transport network that moves electrons between the anode and the current collector interface. The metal-coated fibers function like logs, which are elongated linear electron transport conduits, and the conductive filamentous structures function like twining plants that electrically interconnect the logs.

[0043] When such a combination of additives is used at the anode, the conductivity of the anode is further improved. The carbon powder of the anode is already somewhat conductive, but the spaces between the filamentous networks of the conductive filamentous branched structures are approximately the same dimensions and shape as the particle size of the carbon powder. Thus, the filamentous branched structures somewhat three-dimensionally enclose the carbon particles by themselves, like a spider's web or net (hereinafter referred to as a "nanonet"). This "nanonet" phenomenon leads to a much higher level of electrical interconnectivity between the carbon particles, the filamentous branched structures, the metal-coated fibers, and the current collector foil. This effect is more pronounced for the nanowires due to their smaller diameter and greater degree of branching.

[0044] As shown in the examples given in the following detailed description, the amount of metal coating on the fibers is an important parameter in changing the conductivity.

[0045] These, and other features of the exemplary embodiments of the present invention, will become more fully apparent from the drawings, examples, and the following description, or can be learned by the practice of the invention described below.

[0046] Detailed Description of the Invention Exemplary embodiments of the present disclosure are best understood by reference to the drawings, in which like parts are indicated throughout by like numerals. It will be readily understood that the components of the exemplary embodiments of the present invention can be arranged and designed in a variety of different configurations as schematically depicted and described in the drawings and examples of the present disclosure. Accordingly, the following more detailed description of the exemplary embodiments presented in the drawings and examples is not intended to limit the scope of the invention as set forth in the claims, but merely represents exemplary embodiments of the disclosure.

[0047] This detailed description describes, with reference to the drawings, a representative rechargeable lithium-ion battery 10 known in the prior art, which operates with a standard cathode 12 made of a base cathode material 14 and a standard anode 16 made of a base anode material 18. Exemplary embodiments of the present invention include modified electrodes having increased conductivity that may be components of the enhanced battery, either separately or together.

[0048] Referring to FIG. 1, a representative rechargeable lithium-ion battery 10 known in the prior art is schematically represented. The lithium-ion battery 10 includes a standard cathode 12 made of a base cathode material 14, a standard anode 16 made of a base anode material 18, an electrolyte 20, a separator barrier 22, an anode current collector foil 24, and a cathode current collector foil 26, housed within a battery housing 28. The base cathode material 14 may be any of a number of cathode compounds known to be used in batteries; however, for the purposes of this description, the battery 10 is a lithium-ion battery 10, and exemplary base cathode materials 14 include lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NMC), as well as any other cathode material used in lithium-ion batteries. The base anode material 14 may be any of the anode materials known to be used in batteries; however, for the purposes of this description, the battery 10 is a lithium-ion battery 10, and exemplary base anode materials 14 include carbon power, graphite powder, and any other cathode material used in lithium-ion batteries. Such compounds further contain a small amount of polymer used as a binder. Also, the electrolyte 20 most commonly used in lithium-ion batteries 10 is an organic solution of a lithium salt such as LiPF6. An important role of the electrolyte 20 is to transport positive lithium ions between the cathode 12 and the anode 16.

[0049] Battery 10 operates to transport electrons through a system of components. In FIG. 1, in the discharge mode, electron transport begins at anode current collector foil 24 and then proceeds through the anode foil / active material interface to the anode active material (standard anode 16 in this case). The discharge direction of the electron flow (indicated by schematic flow path 30) is generally indicated by arrow A from negative to positive. Positively charged lithium ions 32 move within electrolyte 20 (in this case, lithium accepts electrons at standard anode 16 during charging), and their electrons and lithium pass through separator barrier 22 (as indicated by dashed arrow B) to reach standard cathode 12. Separation of electrons from lithium (of lithium ions 32) occurs at standard cathode 12. The electrons are transported through the cathode active material (standard cathode 12) to the active material / foil interface and then move the electrons exiting from cathode current collector foil 26 to the device in which it functions.

[0050] FIG. 2 shows battery 10 of FIG. 1 during charging. The charging direction of the electron flow (indicated by schematic flow path 30) reverses as schematically indicated by arrow C from positive to negative. Positively charged lithium ions 32 move within electrolyte 20 from standard cathode 12 through separator barrier 22 (as indicated by dashed arrow D) to standard anode 14.

[0051] Significant improvement in the conductivity of either or both of the anode or cathode results in a lower resistivity not only in the planar or thickness direction of the respective cathode or anode film, but generally also across the entire battery cell. As a result, the lower the resistance, the higher the voltage to move a given current, or the higher the current that moves at a given voltage. This, in turn, results in either faster charge and discharge or the ability to move electrons more easily through a thicker film, thus increasing the capacity. Joule heating is also reduced, corresponding to a reduction in temperature and energy loss. The reduction in operating temperature also leads to a more efficient and safer battery.

[0052] Exemplary conductive additives 34 for the anode 16 and the cathode 12 (see FIGS. 4, 5, 7, and 8) are described in the present disclosure, which significantly improve the conductivity and enhance the performance of these components 12, 16, and the battery 10 in which they are used. By dispersing some of these exemplary additives 34 within the base cathode material 14 and / or the base anode material 18, the resulting reinforced cathode 36 and / or reinforced anode 44 exhibit an increase in conductivity and ion transport within the battery system is promoted. It is also proposed that the non-carbon surface of highly conductive anode additives may inhibit SEI growth.

[0053] FIG. 3 is a representative depiction of a portion of an exemplary embodiment of a cathode 12 generally known in the prior art, showing the base cathode material 14 that makes up the cathode 12. As noted above, the base cathode material 14 may be any of many cathode compounds known to be used in batteries.

[0054] An exemplary embodiment of a reinforced cathode 36 showing metal-coated fibers 38 dispersed throughout the base cathode material 14 is represented in FIG. 4. The depiction in FIG. 4 is not drawn to scale and does not indicate any specific quantity level. Rather, the depiction is merely intended to provide context for the dispersion of the metal-coated fibers 38 within the base cathode material 14.

[0055] FIG. 5 is an enlarged view compared to FIG. 4 and represents an exemplary alternative embodiment of the enhanced cathode 36, showing metal-coated fibers 38 and high aspect ratio conductors 40, such as conductive filamentous structures 42 dispersed throughout the base cathode material 14. Such high aspect ratio conductors 40 are smaller than the metal-coated fibers 38 in at least one physical aspect of the material, such as diameter, mass, or volume, and may further exhibit branching. The electrical conductivity between the conductive metal-coated fibers 38 is further improved by the addition of such high aspect ratio conductors 40. Again, the depiction in FIG. 5 is not drawn to scale and does not indicate any specific quantity level. Rather, the depiction is merely intended to provide context for the dispersion of the metal-coated fibers 38 within the base cathode material 14.

[0056] FIG. 6 is a representative depiction of a portion of an exemplary embodiment of an anode 16 generally known in the prior art, showing the base anode material 18 that creates the anode 16. As described above, the base anode material 16 can be any anode material known to be used in a battery.

[0057] An exemplary embodiment of an enhanced anode 44 showing metal-coated fibers 38 dispersed throughout the base anode material 18 is represented in FIG. 7. The depiction in FIG. 7 is not drawn to scale and does not indicate any specific quantity level. Rather, the depiction is merely intended to provide context for the dispersion of the metal-coated fibers 38 within the base anode material 18.

[0058] Figure 8 is an enlarged view compared to Figure 4 and represents an exemplary embodiment of an alternative enhanced anode 44, showing metal-coated fibers 38 and high aspect ratio conductors 40, such as conductive filamentous structures 42 dispersed throughout the base anode material 18. Such high aspect ratio conductors 40 are smaller than the metal-coated fibers 38 in at least one physical aspect of the material, such as diameter, mass, or volume, and may further exhibit branching. The electrical conductivity between the conductive metal-coated fibers 38 is further improved by the addition of such high aspect ratio conductors 40.

Examples

[0059] Example The following are some representative examples demonstrating the concepts and advancements disclosed in the present disclosure:

[0060] Fiber Selection (Examples 1 - 3)

[0061] Example #1 - Nickel-Coated Carbon Fibers in the Cathode Nickel-coated carbon fibers (7 micron diameter, 40% nickel coating, i.e., 0.25 micron thickness, precision cut to 0.50 mm) provided excellent conductivity in the cathode. The addition of 2 mass% of the described fibers reduced the resistance in the thickness direction of a 100 micron film from 3.5 ohms (without fibers) to 1.5 ohms (2% fibers). However, lithium-ion coin cells fabricated from these films did not cycle. The cells were found to corrode at 3.75 volts before reaching the operating condition of 4.2 volts. This is because the half-cell potentials of nickel and lithium are 3.75 volts. However, this demonstrated that the conductivity could be significantly improved, suggesting that nickel-coated fibers should operate in systems that remain below approximately 3.5 volts (see the following anode examples).

[0062] Example #2 - Aluminum-Coated Fibers The half-cell potential of aluminum and lithium is 4.7 volts. Therefore, aluminum-coated fibers should withstand a cathode having lithium with an operating voltage of 4.2 volts. In this case, a 0.2 micron coating of aluminum was plated over a 0.1 micron coating of nickel on carbon fibers. The doubly coated fibers were cut to a length of 0.50 mm. When 2 mass % of this fiber was added to the cathode, the cell could cycle successfully for about a week, after which the underlying nickel entered into the reaction. When these cathode films were manufactured, the standard cathode (manufactured from the base cathode material) was 90 microns thick, and the fiber-filled cathode (base cathode material filled with metal-coated fibers) was 110 microns thick. This is probably because the added fibers exerted support and resistance, pulling the slightly thicker film. The following table compares the thickness, resistance, voltage, and capacitance of these two cells. (Each value is the average of three samples).

[0063]

Table 1

[0064] Note that the fiber-filled membrane is 23% thicker than the standard membrane, but shows the same resistance and the same voltage as its thinner original membrane. Therefore, the capacitance of the fiber-filled membrane increased by 23%. This means higher capacitance at the same rate (drive resistance), or higher rate at equal capacitance.

[0065] Example #3 - Process of Coating Fibers Containing CVD Aluminum Each of the aforementioned fibers was coated by an aluminum CVD (Chemical Vapor Deposition) process, precision cut to 0.5 mm, and added to the cathode. Examples of fibers include, but are not limited to, silicon carbide, borosilicate, quartz, minerals (basalt), surface-modified carbon, and organic (aramid - Kevlar). In each of these cases, the addition of 1% - 4% of precision-cut aluminum-CVD-coated fibers improved the conductivity of the coating by values similar to those in Example #1 above. Each of these fibers adds certain advantages or disadvantages specific to that particular fiber, but they all act to improve the conductivity of the cathode.

[0066] Cathode (Example 4)

[0067] Example #4 - Precision-cut aluminum-coated fibers to 0.5 mm These coated fibers were dispersed in the standard cathode mixture at 3 wt% (always taking a portion of the mixture for control). This was repeated several times, and the greatest variable was the variation in conductivity between batches of aluminum-coated fibers or fiber types.

[0068] The film was extruded onto aluminum foil using a doctor blade, and a consistent film thickness and mass were achieved by adjusting the height of the blade according to the desired thickness and the ratio of solvent to solid in the mixture. After drying, the non-calendered film was tested for volume resistivity according to ASTM method D2739. The following table reports some of these comparison batches.

[0069]

Table 2

[0070] Using sample set D, the samples were calendered and measured for complex volume resistivity (CVR) and interface resistivity (IR).

[0071]

Table 3

[0072] Example #5 - Higher Fiber Content at the Cathode The standard cathode mixture was filled with 3%, 4%, 5%, and 6% nickel-coated fibers having a 40% nickel coating (250 nm thickness) precision-cut to 0.5 mm. Mixing attempts above 6% resulted in insufficient dispersion. However, the following table showed the improvement in volume resistivity in the thickness direction when films of equal thickness were drawn from these mixtures.

[0073] The volume resistivity of the cathode film was modified with 40% nickel and 0.5 mm long precision-cut nickel-coated carbon fibers.

[0074]

Table 4

[0075] Example #6 - Influence of Nickel Coating Percent on Fibers In the same test as Example #5, one sample was made with a 75% nickel coating on the fiber, and the mass and thickness of nickel on the fiber (carbon fiber) were quadrupled (the reference mass was 0.76 gm / meter, while 40% was 1.28 gm / meter and 75% was 3.00 gm / meter). The density of the 40 nickel-coated fibers was 2.6 gm / cc, while the density of the 75% nickel-coated fibers was 5.5 gm / cc. For this example, the goal was to add a volume that would match that representative of the packing of the 40% nickel-coated fibers. The packing mass range for the 75% nickel-coated fibers could be up to 15% at most, but for this example, 10 mass% was selected. This corresponds to 4.8% fiber volume of the 40% nickel-coated fibers. At this amount, the dispersion went well and the film pulled well. However, the volume resistivity in the thickness direction of this film was outstanding at 0.40 ohm cm, almost twice that of the best amount of the 40% nickel-coated fibers. This higher conductivity and nickel filling result in very improved performance, but further improve the current capacity and make it more suitable for a power cell.

[0076] Anode (Examples 7, 8, and 9)

[0077] Example #7 - Anode containing copper-coated carbon fibers Since the current collector of the anode is a copper foil, copper may be a viable candidate for anode improvement. In this example, up to 8% copper-coated carbon fibers were added to the anode. The copper coating on the AS4 fibers was 40 mass%. The copper-coated carbon fibers were obtained from Technical Fiber Products in Schenectady, New York, and precision cut to 0.50 mm length. The resistivity of the resulting anode was reduced from 253 ohms to 112 ohms, i.e., a 220% improvement in conductivity. As a result, the voltage of the anode was reduced from 1.0 ohm to 0.8 ohm. This lower voltage means a higher capacity at a given charge rate, or alternatively a higher charge rate.

[0078] Example #8 - Anode Containing Precision Cut Nickel-Coated Carbon Fibers (NiPCF) Nickel is a viable element to include in the anode. The precision cut nickel-coated carbon fibers were obtained from The Conductive Group of Heber City, Utah. The nickel coating on the AS4 carbon fibers was 40 wt%, i.e., 0.25 microns thick. Recall that the anode was already composed of conductive graphite powder. The addition of 5 wt% or 10 wt% of NiPCF alone did little to significantly improve the conductivity (CVR or IR) of the anode film. While there were samples that did not show a statistically significant improvement, on the other hand, there were samples that perhaps showed an improvement of about 25%. These improvements are thought to be at their limit.

[0079] Example #9 - Anode Containing Filamentous Branch Structures Nickel powder produced by chemical vapor decomposition may be produced in two distinct geometric classes; spherical (Type 1 powder), or filamentous (Type 2 powder). Type 1 powder is of little use in increasing conductivity until the amount becomes disproportionately high because the particles need to be in close contact with each other. However, filamentous powder becomes conductive in less quantity due to its higher aspect ratio and, in part, the filamentous nature which usually exhibits some degree of branching. These powders in larger diameter forms (usually with the main branch diameter exceeding 1 micron) are available through Vale or Novamet, particularly as Chip 255 powder (and its derivatives). Nanostrands are filamentous branched metals with smaller diameters that contain a wider range of branching. Nanostrands are available from The Conductive Group of Heber City, Utah.

[0080] The conductivity of the system increased little with Type 255 powder alone. However, nanostrands showed a significant increase in the conductivity of the anode mixture.

[0081] What is interesting is the combination of NiPCF fibers and filamentous branched structures, which form a so-called "log and twister grass" network.

[0082] The following table compares the CVR and IR of the standard anode film with those of 5% NiPCF, 5% type 255, 5% nanostrand, and 5%+5% NiPCF / 255, and 5%+5% NiPCF / nanostrand:

[0083]

Table 5

[0084] The CVR of the individual additives does not seem to be very effective, but it is noted that the combination somewhat changes the CVR. They all have some effect on the IR, and some are very significant. This is presumably because none of the individual additives are as conductive as carbon powder. However, the "log and twister grass" provides more complex opportunities for electron transport. The IR, i.e., the interfacial resistance, suggests that the combination of additives takes multiple paths directly to the underlying foil across the ever-present polymer binder barrier. Calendering seems to provide additional physical pressing of the conductor into the foil.

[0085] The filamentous branched structures (twister grass) not only provide multiple high aspect ratio paths to the nickel-coated fibers (logs), but they also tend to lie across or contact carbon particles at multiple locations (hereinafter each such contact is referred to as a "contact point"). It was observed that when using more open and branched nanostrands, they tend to wrap around and enclose carbon particles by themselves, forming a nanonet and showing a large number of contact points, like a spider's web or net. Adding more opportunities for conduction is this mode of multiple contacts and nanonet formation. It becomes a "log, twister grass, and nanonet" model, uniquely constructed in its ability to collect electricity at higher speeds, higher amperages, and lower voltages.

[0086] The NiPCF / nanostrand sample was selected for the anode and used to fabricate a laboratory pouch cell battery together with the cathode described near the end of Example 4.

[0087] Pouch cells (Examples 10 and 11)

[0088] Example #10 - Modified anode with standard cathode The control pouch cell was fabricated using a standard cathode and a standard anode. The second pouch cell was constructed using a standard cathode and an anode modified with nickel-coated fibers. The standard anodes had CVR and IR values of 0.12 and 0.10 ohms, respectively. The modified anodes had CVR and IR of 0.065 and 0.0081, respectively. Thus, the CVR and IR of the modified anodes were improved by 1.9x and 12.3x, respectively. The capacities at various discharge rates as a result of the improved conductivity are shown in the following table:

[0089]

Table 6

[0090] This is thought to be due to the conductive network of the above-mentioned bamboo, kudzu, and nanonet, and such a structure collects and transports electrons more efficiently. It was also observed that the bamboo and kudzu create a more open structure. Thus, it seems that more and easier paths are created for lithium ion transport.

[0091] Example #11 - Modified cathode with standard anode For this example, the pouch cell was constructed using a standard anode and a lithium iron phosphate cathode. While the control cell used a standard lithium iron phosphate cathode, the second cell used a cathode containing 3% (by mass) of 40% nickel-coated carbon fibers precision-cut to 0.5 mm, which gave the results of Example #5. This is a rather conservative amount.

[0092] The following table shows the discharge voltage and capacity of these cells at various discharge rates.

Table 7

[0093] This data shows that the addition of a suitable amount of conductive fibers to the cathode simultaneously reduces the resistance and impedance, enabling a higher voltage or current, or both.

[0094] Regarding the exemplary methods or processes of the present invention, the order and / or arrangement of the steps described in this disclosure are exemplary and not limiting. Thus, the steps of various processes or methods may be shown and described as being in an order or temporal arrangement, but the steps of any such process or method are not limited to being carried out in any particular order or arrangement unless otherwise indicated. In fact, the steps of such processes or methods can usually be carried out in different orders and arrangements, which still fall within the scope of the present invention.

[0095] In addition, any mention of advantages, benefits, unexpected results, preferred materials, or practicability of the present invention is not intended to confirm that the present invention has been pre - reduced for implementation or that any tests have been conducted. Similarly, unless otherwise stated, the use of verbs in the past tense (present perfect or past tense) is not intended to indicate or suggest that the present invention has been pre - reduced for implementation or that any tests have been conducted.

[0096] Exemplary embodiments of the present invention are described above. No element, act, or recitation used in this description should be construed as critical, necessary, essential, or indispensable to the present invention unless explicitly described as such. Although only a few exemplary embodiments are described in detail in this disclosure, those skilled in the art will readily recognize that many modifications are possible in these exemplary embodiments without substantially departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the present invention as defined in the appended claims.

[0097] In the claims, any means-plus-function clause is intended to cover the structures described in this disclosure as performing the recited function and is intended to cover not only structural equivalents but also equivalent structures. Thus, nails and screws may not be structural equivalents in that a nail uses a cylindrical surface to fasten wooden parts and a screw uses a helical surface in an environment where it fastens wooden parts, but nails and screws may be equivalent structures. An interpretation under 35 U.S.C. § 112 is not intended unless the exact phrase "means for" (performing a particular function or step) is recited in the claims. Additionally, it is not intended that the scope of patent protection granted to the present invention be defined by reading into any claim limitations found in the disclosure that are not explicitly recited in the claims themselves.

[0098] Although specific embodiments and applications of the present invention have been described, it should be understood that the present invention is not limited to the exact construction and components disclosed in this disclosure. Various modifications, changes, and variations apparent to those skilled in the art can be made in the construction, operation, and details of the methods and systems of the present invention disclosed in this disclosure without departing from the spirit and scope of the present invention.

[0099] Those skilled in the art will understand that this embodiment can be implemented in other specific forms without departing from the structures, methods, or other essential features widely described in this disclosure and recited in the following claims. The described embodiments are to be construed as illustrative in all respects and not restrictive. Accordingly, the scope of the present invention is indicated by the appended claims rather than by the foregoing description. All modifications within the meaning and range of equivalents of the claims are to be embraced within their scope. The present disclosure also includes the following. Aspect 1 A battery cathode having improved electrical conductivity for use in a battery having an electrolyte with an electromotive potential, wherein the battery cathode has a base cathode material having an operating voltage; and includes at least one additive that forms a dispersion mixture dispersed within the base cathode material, wherein the at least one additive includes a plurality of metal-coated fibers having a diameter of 3 microns to 20 microns, the thickness of the metal coating being 0.1 micron to 3 microns; the fiber length being 0.1 mm to 1.0 mm, the metal-coated fibers including a metal having an electromotive potential, the selection of the metal for the metal coating and the thickness of the metal coating affecting the electrical conductivity and the electromotive reactivity; the fiber diameter and the fiber length of the metal-coated fibers affecting the aspect ratio, the surface area, and the dispersibility of the metal-coated fibers within the base cathode material, and the dispersion mixture imparting improved electrical and mechanical properties to the battery cathode; A battery cathode, wherein since the metal may undergo a corrosion reaction with the electrolyte at the reaction voltage, the operating voltage of the base cathode material remains lower than the reaction voltage of the metal with respect to the electrolyte. Aspect 2 The battery cathode according to Aspect 1 above, wherein the electrical conductivity between the conductive fibers is further improved by the addition of a high aspect ratio conductor smaller than the metal-coated fibers. Aspect 3 The battery cathode according to Aspect 2 above, wherein the high aspect ratio conductor has a branched structure. Aspect 4 The electrolyte contains lithium, The battery cathode according to Aspect 1 above, wherein when the operating voltage of the base cathode material exceeds 3.76 volts, the metal-coated fibers include aluminum-coated fibers. Aspect 5 The electrolyte contains lithium, The battery cathode according to Aspect 1 above, wherein when the operating voltage of the base cathode material is less than 3.76 volts, the metal-coated fibers include nickel-coated fibers. Aspect 6 The battery cathode according to the above aspect 1, wherein the fiber is selected from the group of materials consisting of carbon, pan ox, silica, quartz, silicate, alumina, aluminosilicate, borosilicate, glass, mineral, carbide, nitride, boride, polymer, cellulose, inorganic fiber, and organic fiber. Aspect 7 The battery cathode according to the above aspect 1, wherein the metal-coated fiber is precisely cut to the desired length such that the metal-coated fiber is within a range of ±10% of the desired length. Aspect 8 The battery cathode according to the above aspect 1, wherein the fiber has a carbide surface, the carbide surface is chemically acceptable for aluminum deposition, and the aluminum deposition is deposited from any aluminum-containing organometallic compound. Aspect 9 The battery cathode according to the above aspect 1, wherein the metal-coated fiber is dispersed in the base cathode material in a maximum filling mass range of 15%, whereby the battery cathode shows a reduction in volume resistivity and interfacial resistivity with respect to the unfilled base cathode material. Aspect 10 The improved electrical and mechanical properties of the dispersion mixture with respect to the base cathode material include at least one improvement in the group of improvements consisting of improved electrical conductivity of the battery cathode, lower resistance, lower impedance, increased voltage capacity, increased ampere-hour capacity, increased speed and power, lower Joule heating, lower and safer operating temperature, and balanced higher capacity, according to the above aspect 1. Aspect 11 A battery anode having improved electrical conductivity, used in a battery having an anode electrolyte with an electromotive potential, the battery anode comprising a base anode material having an operating voltage; and at least one anode additive dispersed in the base anode material to form an anode dispersion mixture and the at least one anode additive is Comprising a plurality of metal-coated fibers having a diameter of 3 microns to 20 microns, the thickness of the metal coating being 0.1 micron to 3 microns; the fiber length being 0.1 mm to 1.0 mm, said metal-coated fibers comprising a metal having an electromotive potential, the selection of the metal and thickness for said metal coating affecting electrical conductivity and electromotive reactivity; the fiber diameter and fiber length of said metal-coated fibers affecting the aspect ratio, surface area, and dispersibility of said metal-coated fibers within said base anode material, said anode dispersion mixture of metal-coated fibers characterized thus in said base anode material imparting improved electrical and mechanical properties to said battery anode; Since said metal may undergo a corrosion reaction with said anode electrolyte at the reaction voltage, the operating voltage of said base anode material remains lower than said reaction voltage of said metal with respect to said anode electrolyte, a battery anode. Aspect 12 The battery anode according to aspect 11 above, wherein the electrical conductivity between said conductive fibers is further improved by the addition of a high aspect ratio conductor smaller than said metal-coated fibers. Aspect 13 The battery anode according to aspect 11 above, wherein said base anode material comprises carbon powder of finely divided carbon powder particles. Aspect 14 The battery anode according to aspect 11 above, wherein said metal coating of said metal-coated fibers is selected from the group of metals consisting of nickel, copper, and aluminum. Aspect 15 The battery anode according to aspect 11 above, wherein said fibers are selected from the group of materials consisting of carbon, pan ox, silica, quartz, silicate, alumina, aluminosilicate, borosilicate, glass, mineral, carbide, nitride, boride, polymer, cellulose, inorganic fiber, and organic fiber. Aspect 16 The battery anode according to aspect 11 above, wherein said plurality of metal-coated fibers are dispersed in said base anode material within a maximum filling mass range of 15%. Aspect 17 The improved electrical and mechanical properties of the anode dispersion mixture with respect to the base anode material include at least one improvement in the group of improvements consisting of improved electrical conductivity of the battery anode, lower resistance, lower impedance, increased voltage capacity, increased ampere-hour capacity, increased speed and power, lower joule heating, lower and safer operating temperature, and balanced higher capacity, the battery anode according to aspect 11 above. Aspect 18 A battery having improved electrical conductivity with an electrolyte having an electromotive potential, the battery including a battery cathode and a battery anode, The battery cathode includes A base cathode material having an operating voltage; At least one additive dispersed in the base cathode material to form a dispersion mixture Including The at least one additive Includes a plurality of metal-coated fibers having a diameter of 3 microns to 20 microns, the thickness of the metal coating is 0.1 micron to 3 microns; the fiber length is 0.1 mm to 1.0 mm, and the metal-coated fibers include a metal having an electromotive potential, and the selection of the metal for the metal coating and the thickness of the metal coating affect electrical conductivity and electromotive reactivity; the fiber diameter and fiber length of the metal-coated fibers affect the aspect ratio, surface area, and dispersibility of the metal-coated fibers in the base cathode material, and the dispersion mixture imparts improved electrical and mechanical properties to the battery cathode; Since the metal may undergo a corrosion reaction with the electrolyte at the reaction voltage, the operating voltage of the base cathode material remains lower than the reaction voltage of the metal with respect to the electrolyte, The battery anode includes A base anode material having an operating voltage; and At least one anode additive dispersed in the base anode material to form an anode dispersion mixture Including The at least one anode additive Comprising a plurality of metal-coated fibers having a diameter of 3 microns to 20 microns, the thickness of the metal coating being 0.1 micron to 3 microns; the fiber length being 0.1 mm to 1.0 mm, said metal-coated fibers comprising a metal having an electrification potential, the selection of the metal and thickness for said metal coating affecting electrical conductivity and electrification reactivity; the fiber diameter and fiber length of said metal-coated fibers affecting the aspect ratio, surface area, and dispersibility of said metal-coated fibers within said base anode material, said anode dispersion mixture of metal-coated fibers characterized in this way within said base anode material imparting improved electrical and mechanical properties to said battery anode; A battery in which, since said metal may undergo a corrosion reaction with said anode electrolyte at the reaction voltage, the operating voltage of said base anode material remains lower than said reaction voltage of said metal with respect to said anode electrolyte. Aspect 19 The battery according to aspect 18 above, wherein the addition of a high aspect ratio conductor smaller than said metal-coated fibers further improves the electrical conductivity at said battery cathode between said conductive metal-coated fibers. Aspect 20 The battery according to aspect 18 above, wherein the addition of a high aspect ratio conductor smaller than said metal-coated fibers further improves the electrical conductivity at said battery anode between said conductive metal-coated fibers.

Explanation of Symbols

[0100] Reference number Lithium-ion battery or battery 10 Standard cathode or cathode 12 Base cathode material 14 Standard anode or anode 16 Base anode material 18 Electrolyte 20 Separator barrier 22 Anode current collector foil 24 Cathode current collector foil 26 Battery housing 28 Schematic flow path 30 Lithium ion 32 One or more additives 34 Reinforced cathode 36 Metal-coated fiber 38 High aspect ratio conductor 40 Conductive filamentous structure 42 Reinforced anode 44 Arrow A (discharge direction) Dashed arrow B (discharge direction) Arrow C (charge direction) Dashed arrow D (charge direction)

Claims

1. A battery anode having improved electrical conductivity for use in a battery, wherein the battery anode comprises a base anode material containing carbon; and at least one anode additive dispersed within the base anode material to form an anode dispersion mixture comprising the at least one anode additive comprising a first anode additive comprising a plurality of metal-coated fibers having a diameter of 3 microns to 20 microns, the thickness of the metal coating being 0.1 micron to 3 microns; the fiber length being 0.1 mm to 1.0 mm, the first anode additive being fibers that are aluminum CVD-coated and do not form carbides, and being dispersed in the base anode material within a maximum filling mass range of 8% of the base anode material, a battery anode.

2. The battery anode according to claim 1, wherein the base anode material comprises carbon powder of finely divided carbon powder particles.

3. The battery anode according to claim 1, wherein the fibers are selected from the group consisting of materials comprising carbon, silica, quartz, silicate, alumina, aluminosilicate, borosilicate, glass, mineral, carbide, nitride, boride, polymer, cellulose, inorganic fiber, and organic fiber.

4. The battery anode according to claim 1, further comprising a second anode additive comprising a filamentous branched structure of conductive nickel, the filamentous branched structure of conductive nickel being selected from the group consisting of branched nickel powder and nickel nanowires.

5. The battery anode according to claim 4, wherein the second anode additive is nickel nanowires.

6. The battery anode according to claim 1, wherein the fibers that do not form carbides are selected from the group consisting of materials comprising surface-modified carbon, silica, quartz, silicate, alumina, aluminosilicate, borosilicate, glass, mineral, carbide, nitride, boride, polymer, cellulose, inorganic fiber, and organic fiber.

7. A battery anode having improved electrical conductivity for use in a battery, wherein the battery anode comprises a base anode material containing carbon; and at least one anode additive dispersed within the base anode material to form an anode dispersion mixture comprising the at least one anode additive comprising A first anode additive comprising aluminum CVD-coated fibers having a diameter of 3 microns to 20 microns, wherein the thickness of the metal coating is 0.1 micron to 3 microns; the fiber length is 0.1 mm to 1.0 mm, wherein the fibers of the aluminum CVD-coated fibers are fibers that do not form carbides, the first anode additive is dispersed in the base anode material within a filling mass range of up to 15% of the base anode material, a battery anode.

8. The battery anode according to claim 7, further comprising a second anode additive comprising a conductive nickel filamentous branched structure, wherein the conductive nickel filamentous branched structure is selected from the group consisting of branched nickel powder and nickel nanowires.

9. The battery anode according to claim 8, wherein the second anode additive is nickel nanowires.

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