Active material containing a blend of alkaline and acidic metal oxides

Abstract

The battery cell (100) of the present disclosure includes a zinc anode (106) and a cathode (104) having an acidified metal oxide nanomaterial in combination with an alkaline battery chemistry.

Description

[Technical field]

[0001] The present disclosure is in the field of materials and methods of construction useful for chemical energy storage and power devices, such as, but not limited to, batteries. [Background technology]

[0002] Metal oxides are compounds in which oxygen is bonded to a metal, m O x They are compounds with the general formula: They are found in nature but can be artificially synthesized. In synthetic metal oxides, the synthesis method can have a wide range of effects on the surface properties, including their acid / base properties. Changes in the surface characteristics can alter the properties of the oxide, affecting things like its catalytic activity and electron mobility. However, the mechanisms by which the surface controls reactivity are not always well characterized or fully understood. For example, in photocatalysis, surface hydroxyl groups are thought to facilitate the transfer of electrons from the conduction band to chemisorbed oxygen molecules.

[0003] Despite the importance of surface properties, the metal oxide literature, both academic papers and patents, has focused primarily on creating novel nanoscale crystalline forms of metal oxides to improve energy storage and power applications. Metal oxide surface properties have been neglected, and outside of the chemical catalysis literature, very little innovation has been directed toward controlling or modifying the surfaces of known metal oxides to achieve performance goals.

[0004] The chemical catalysis literature has focused primarily on the creation of "superacids" that are more acidic than pure sulfuric acid (18.4M H2SO4), which is often used for large-scale reactions such as cracking hydrocarbons. Superacidity cannot be measured on the conventional pH scale, but is instead quantified by the Hammett number. The Hammett number (H0) can be thought of as extending the pH scale into negative numbers below zero. Pure sulfuric acid has an H0 of -12.

[0005] However, there are many reaction systems and many applications where superacidity is too strong. For example, superacidity may degrade components of the system or catalyze undesirable side reactions. However, acidity may still be useful in these same applications because it provides enhanced reactivity and rate properties or enhanced electron mobility.

[0006] The battery literature teaches that acidic groups are detrimental to batteries, attacking metal current collectors and housings and potentially degrading other electrode components. Additionally, the prior art teaches that active catalytic electrode surfaces can lead to electrolyte decomposition, resulting in gassing inside the cell and ultimately causing cell failure.

[0007] A need exists for battery packaging having a synthetic metal oxide disposed within the anode and / or cathode that is acidic at least on its surface, but not super acidic. Additionally, existing battery construction techniques should be updated to take full advantage of the new materials available in accordance with the present disclosure, as well as to take advantage of the advantages and improvements that can be realized using such construction techniques with known materials. Summary of the Invention [Means for solving the problem]

[0008] An embodiment of a super-high capacity battery cell has a lithiation capacity of at least 4000 mAhr / g and includes an electrode including a layer containing a nanoparticle-sized metal oxide in the range of 20% to 40% by weight and a nanoparticle-sized conductive carbon in the range of 20% to 40% by weight. In a specific embodiment, the metal oxide and conductive carbon are each 33% by weight. In a further embodiment, the metal oxide and conductive carbon are each 20% to 25% by weight. In a further specific embodiment, the metal oxide and conductive carbon are each 21% by weight. The electrode can be configured as an anode or a cathode.

[0009] The battery cell may also include nanoparticle-sized conductive carbon and at least one other layer disposed adjacent to the layer containing nanoparticle-sized metal oxide. In some embodiments, the other layer is both above and below the layer containing nanoparticle-sized metal oxide. The nanoparticle-sized metal oxide may be an acidified metal oxide (hereinafter, acidified metal oxide, or "AMO") having, at least on its surface, a pH<5 when measured at 5% by weight in water, and a Hammett function>-12. In other embodiments, metal oxides that are not acidified, substantially not acidified, or not functionalized with acidic groups (hereinafter, non-acidified metal oxide, or "non-AMO") may be used in the construction of the cell or battery. Collectively, AMOs and non-AMOs may simply be referred to as metal oxides.

[0010] This disclosure describes the use of AMO, non-AMO corresponding materials, and both. Applications include, but are not limited to, battery electrode materials, catalysts, photovoltaic or photoactive components, and sensors. Further disclosed are techniques for making AMO and non-AMO, and devices that include either. The disclosed AMOs can be optionally used in combination with acidic species to enhance their usefulness.

[0011] The present application further describes high capacity electrochemical cells that include electrodes that include AMO and non-AMO. Techniques for preparing metal oxides and electrochemical cells that include metal oxides are further disclosed. Optionally, the disclosed metal oxides may be used in combination with conductive materials to form electrodes. The formed electrodes are useful with metallic lithium as a corresponding counter electrode and with conventional lithium ion electrodes. Optionally, the disclosed metal oxides may be used in combination with acidic species to enhance their usefulness.

[0012] In some embodiments, the present disclosure provides layered electrode structures with low active material (i.e., metal oxide) loading. In some cases, less than 80 wt% active material is used in the electrode. This is in contrast to conventional electrochemical cell technologies that attempt to maximize active material loading, which may be about 80 wt% or more, such as 90 wt% or 95 wt% or 99 wt%. While high active material loadings may be useful to increase capacity in conventional electrochemical cell technologies, the inventors of the present application have found that lower active material loadings actually enable higher cell capacity using various embodiments according to the present disclosure. Such increased capacity may be achieved at least in part by allowing more shuttle ions (i.e., lithium ions) to be absorbed, since additional physical volume may be available at lower active material loading levels. Such increased capacity may alternatively or additionally be achieved at least in part by allowing more active sites to absorb shuttle ions, resulting in less blocking of active sites by additional material mass.

[0013] The described metal oxides include those in the form of nanomaterials, such as nanoparticle forms, which may be monodisperse or substantially monodisperse, e.g., having a particle size of less than 100 nm. The disclosed AMOs, at certain concentrations (e.g., 5% by weight), when suspended in water or resuspended in water after drying, exhibit a low pH, such as less than 7 (e.g., between 0 and 7), and further exhibit a Hammett function H0 of greater than -12 (i.e., not super acidic), at least on the surface of the AMO.

[0014] The surface of the AMO may optionally be functionalized, such as with acidic or other electron-withdrawing species. Synthesis and surface functionalization may be accomplished in a "single-pot" hydrothermal method that functionalizes the surface of the metal oxide as it is being synthesized from the appropriate precursors. In some embodiments, this single-pot method does not require any additional step or steps for acidification beyond those required to synthesize the metal oxide itself, and results in an AMO material with the desired surface acidity (but not super acidic).

[0015] Optionally, surface functionalization may be performed using strong electron withdrawing groups ("EWGs") such as SO4, PO4, halogens (Br, Cl, etc.), either alone or in combination with each other. Surface functionalization may also be performed with EWGs that are weaker than SO4, PO4, or halogens. For example, synthetic metal oxides may be surface functionalized with acetate (CH3COO), oxalate (C2O4), and citrate (C6H5O7) groups.

[0016] Despite conventional wisdom that acidic species are undesirable in batteries because they can attack metal current collectors and housings and cause degradation of other electrode components, and active catalytic electrode surfaces can lead to electrolyte decomposition, gassing within the cell, and ultimately cell failure, the inventors have discovered that acidic species and components can be advantageous in batteries that use AMO materials in the battery electrodes.

[0017] For example, the combination or use of metal oxides and acidic species can improve the performance of the resulting material, system, or device, improving the capacity, cycling characteristics, and life of the device. As an example, batteries using acidic electrolytes or electrolytes containing acidic species as described herein exhibit significant capacity increases, such as up to 100 mAh / g or more, over similar batteries using non-acidified electrolytes or electrolytes lacking acidic species. In some embodiments, improvements can be achieved in capacity between 50-300 mAh / g. Additionally, absolute capacities of up to 1000 mAh / g or more can be achieved using batteries having acidified electrolytes or electrolytes containing acidic species. Furthermore, the cycle life of the battery can be improved with the use of acidic electrolytes or electrolytes containing acidic species, such that the cycle life of the battery is extended up to 100 or more charge / discharge cycles.

[0018] An exemplary battery cell includes a first electrode, e.g., a first electrode including a metal oxide (which may optionally be an AMO nanomaterial), a conductive material, and a binder, a second electrode, e.g., a second electrode including metallic lithium, and an electrolyte disposed between the first and second electrodes. Optionally, the metal oxide may comprise less than 80 weight percent of the first electrode. Exemplary electrolytes include electrolytes including metal salts dissolved in a solvent, solid electrolytes, and gel electrolytes. Optionally, a separator may be disposed between the first and second electrodes.

[0019] Additionally or alternatively, batteries containing electrodes, such as cathodes or anodes, that are themselves acidic or contain acidic species, such as organic acids, may also be beneficial, again contrary to conventional teachings in battery technology. For example, batteries incorporating acidic electrodes or acidic species within the electrodes may improve performance and increase capacity, cycling characteristics, and life. Capacity increases of up to 100 mAh / g or more can be achieved. The cycle life of a battery may also be improved by the use of acidic electrodes or electrodes containing acidic species, such as when the cycle life of a battery is extended by up to 100 cycles or more. As an example, an acidic electrode or an electrode containing acidic species may exhibit a pH of less than 7 (but not super acidic), such as when the components of the electrode are suspended in water (or resuspended in water after drying) at 5% by weight.

[0020] An electrode according to the present disclosure may include a layered structure including a first set of layers including a conductive material and a second set of layers including a metal oxide. Optionally, the first set of layers and the second set of layers may be provided in an alternating configuration. Optionally, the first set of layers and the second set of layers may independently include 1 to 20 layers. Optionally, the first set of layers and the second set of layers independently have a thickness between 1 μm and 50 μm, between 2 μm and 25 μm, between 3 μm and 20 μm, between 4 μm and 15 μm, or between 5 μm and 10 μm. Optionally, the metal oxide may comprise between 5 and 90 weight percent of the second set of layers, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 weight percent of the second set of layers. Optionally, the conductive material and binder may each independently comprise between 5 and 90 weight percent of the first layer set, for example, 25, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 weight percent of the first layer set.

[0021] The first electrode may optionally include a metal oxide up to 95 weight percent of the first electrode, up to 80 weight percent of the first electrode, up to 70 weight percent of the first electrode, between 1-50 weight percent of the first electrode, between 1-33 weight percent of the first electrode, between 15-25 weight percent of the first electrode, between 55-70 weight percent of the first electrode, between 20-35 weight percent of the first electrode, between 5-15 weight percent of the first electrode. Specific examples of metal oxide weight percent of the first electrode include 1%, 5%, 11%, 12%, 13%, 14%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 60%, 61%, 62%, 63%, 64%, 65%, etc. Without limitation, the loading (percent of metal oxide) of the electrode may range from 1-95%, 10-80%, 20-70%, 30-40%, 40-50%, 50-60%, 60-70%, or 80-100%. In various embodiments, the loading values ​​may vary by ±1%, 2%, 5%, or 10%. Optionally, the conductive material and binder may each independently comprise the majority of the remainder of the first electrode. For example, the conductive material and binder each independently comprise between 10-74 weight percent of the first electrode. Optionally, the conductive material and binder each together comprise between 20-90 weight percent of the first electrode. Optionally, the AMO nanomaterial may be added as a dopant at 1-10 weight percent to a conventional lithium ion electrode, such as graphite, lithium cobalt oxide, etc.

[0022] A variety of materials are useful for the electrodes described herein. Examples of metal oxides include, but are not limited to, lithium-containing oxides, aluminum oxide, titanium oxide, manganese oxide, iron oxide, zirconium oxide, indium oxide, tin oxide, antimony oxide, bismuth oxide, or any combination thereof. Optionally, the oxide may be in the form of AMO. As described herein, the metal oxide optionally includes and / or is surface functionalized with one or more electron-withdrawing groups selected from Cl, Br, BO3, SO4, PO4, NO3, CH3COO, CO4, C2H2O4, C6H8O7, or C6H5O7. Examples of conductive materials include one or more of graphite, conductive carbon, carbon black, Ketjen black, or conductive polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonate (PSS), PEDOT:PSS composites, polyaniline (PANI), or polypyrrole (PPY).

[0023] In some embodiments, an electrode comprising an AMO nanomaterial is used in combination with another electrode to form a cell. For example, the second electrode of such a cell may comprise graphite, metallic lithium, sodium metal, lithium cobalt oxide, lithium titanate, lithium manganate, lithium nickel manganese cobalt oxide (NMC), lithium iron phosphate, lithium nickel cobalt aluminum oxide (NCA), AMO nanomaterial, or any combination thereof. In certain embodiments, the first electrode comprises SnO2 (in AMO or non-AMO form) and the second electrode comprises metallic lithium.

[0024] A variety of materials are useful for the electrodes described herein. Examples of metal oxides include, but are not limited to, lithium-containing oxides, aluminum oxide, titanium oxide, manganese oxide, iron oxide, zirconium oxide, indium oxide, tin oxide, antimony oxide, bismuth oxide, or any combination thereof. Optionally, the oxide may be in the form of AMO. As described herein, the metal oxide optionally includes and / or is surface functionalized with one or more electron-withdrawing groups selected from Cl, Br, BO3, SO4, PO4, NO3, CH3COO, CO4, C2H2O4, C6H8O7, or C6H5O7. Examples of conductive materials include one or more of graphite, conductive carbon, carbon black, Ketjen black, or conductive polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonate (PSS), PEDOT:PSS composites, polyaniline (PANI), or polypyrrole (PPY).

[0025] In various embodiments, a high capacity battery cell includes a first electrode including a metal oxide nanomaterial, a conductive material, and a binder, a second electrode, and an electrolyte disposed between the first electrode and the second electrode, where the metal oxide nanomaterial comprises 5-15, 20-35, or 55-70 weight percent of the first electrode, and the metal oxide nanomaterial includes 0-15 weight percent iron oxide and 85-100 weight percent tin oxide. In some embodiments, the metal oxide includes and / or is surface functionalized with one or more electron-withdrawing groups, the conductive material includes one or more of graphite, conductive carbon, carbon black, Ketjen black, and a conductive polymer such as poly(3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonate (PSS), PEDOT:PSS composite, polyaniline (PANI), or polypyrrole (PPY), and the second electrode comprises or includes metallic lithium.

[0026] Such high capacity battery cells may exhibit a cycle life of 100-1000 charge / discharge cycles without failure, and an open circuit voltage upon assembly between 2 V and 4 V. Optionally, the first electrode may comprise a layered structure including a first set of layers including a conductive material and a second set of layers including a metal oxide nanomaterial, the first set of layers and the second set of layers being provided in an alternating configuration, the first set of layers including between 1-20 layers and the second set of layers including between 1-20 layers, the first set of layers and the second set of layers independently having a thickness between 1 μm and 50 μm, and the metal oxide nanomaterial may comprise between 5-70 weight percent of the second set of layers.

[0027] As a further example, batteries in which electrodes are formed using slurries may also be beneficial and may go against conventional teachings in battery technology. As described herein, metal oxides may be formed into battery electrodes by first forming a slurry of the metal oxide with one or more binder compounds, solvents, additives (e.g., conductive or acidic additives), and / or optionally other wet processing materials. The slurry may be deposited onto a conductive material or current collector to form an electrode. Such slurries and / or solvents may optionally be acidic or include acidic species, again which may allow for improved capacity, cycling characteristics, and life of the resulting battery. Optionally, all or a portion of the solvent may be evaporated, leaving behind the metal oxide material, binders, additives, etc. The resulting material (when using AMO) may exhibit its own acidity, such as having a pH of less than 7 (but not super acidic) when suspended in water (or resuspended in water after drying) at 5 wt.%.

[0028] Various techniques can be used to make the metal oxide. Optionally, the steps of making the metal oxide include forming a solution containing a metal salt, ethanol, and water, acidifying the solution by adding an acid to the solution, basifying the solution by adding an aqueous base to the solution, collecting a precipitate from the solution, washing the precipitate, and drying the precipitate.

[0029] Optionally, the step of fabricating the electrode may further include depositing an additional conductive layer on the electrode layer, such as a conductive layer comprising a second conductive material. Optionally, the step of depositing the conductive layer may include forming a conductive slurry using a second conductive material, a second binder, and a second solvent, depositing the conductive slurry layer on the electrode layer, and evaporating at least a portion of the second solvent to form the conductive layer. Optionally, the step of fabricating the electrode may include forming 1-20 additional conductive layers comprising a conductive material, and 1-20 additional electrode layers comprising a metal oxide. For example, the electrode may include a layered structure comprising a first set of layers comprising the second conductive material and a second set of layers comprising a metal oxide, the first set of layers and the second set of layers being provided in an alternating configuration. Exemplary layers include layers independently having a thickness between 1 μm and 50 μm. Exemplary layers include layers comprising between 10 and 90 weight percent metal oxide. Exemplary layers include layers comprising between 5 and 85 weight percent conductive material and / or binder, independently.

[0030] Electrodes formed using the method of this embodiment may have a metal oxide content of up to 80 percent by weight. Electrodes formed using the method of this embodiment may have a conductive material and / or binder content of between 10 and 70 percent by weight of the electrode.

[0031] As mentioned above, the acidic species may be optionally included as an additive in any of the battery components, such as the electrodes or the electrolyte. Optionally, a battery including a metal oxide according to the present disclosure may include an electrolyte disposed between the electrodes, in which the acidic species is dissolved in a solvent. Such an electrolyte may also be referred to herein as an acidified electrolyte. The electrolyte may optionally include one or more lithium salts dissolved in a solvent, such as LiPF6, LiAsF6, LiClO4, LiBF4, LiCF3SO3, and combinations thereof. It will be understood that the electrolyte may be disposed in the space separating the electrodes (i.e., between the electrodes), as well as permeate or infiltrate the pores of the electrodes and / or permeate or infiltrate the pores of any material or structure that may be optionally disposed between the electrodes, such as the separator.

[0032] Examples of acidic species useful with the AMOs, electrodes, and electrolytes described herein include, but are not limited to, organic acids, such as carboxylic acids. Examples of acidic species include those that exhibit a pKa in water between -10 and 7, between -5 and 6, between 1 and 6, between 1.2 and 5.6, or about 4. Specific examples of organic acids include, for example, oxalic acid, carbonic acid, citric acid, maleic acid, methylmalonic acid, formic acid, glutaric acid, succinic acid, methylsuccinic acid, methylenesuccinic acid, citraconic acid, acetic acid, and benzoic acid. Examples of organic acids include dicarboxylic acids, such as

[0033] [ka] Formula (wherein R is a substituted or unsubstituted C1-C20 hydrocarbon, such as a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aromatic or heteroaromatic group, or a substituted or unsubstituted amine). Examples of organic acids include:

[0034] [ka] Formula (wherein L is a substituted or unsubstituted C1-C20 divalent hydrocarbon such as a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted heteroarylene group, or a substituted or unsubstituted amine). Examples of the organic acid include organic acid anhydrides, for example

[0035] [ka] Formula (In the formula, R 1 and R 2 are independently a substituted or unsubstituted C1-C20 hydrocarbon, such as a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aromatic or heteroaromatic group, or a substituted or unsubstituted amine. 1 and R 2 can form a ring. Examples of organic acid anhydrides include the anhydrides of any of the organic acids mentioned above. Specific organic acid anhydrides include, but are not limited to, glutaric anhydride, succinic anhydride, methylsuccinic anhydride, maleic anhydride, and itaconic anhydride.

[0036] Useful concentrations of acidic species in either or both of the electrolyte and the AMO electrode include 0% to 10% by weight, 0.01% to 10% by weight, 0.1% to 10% by weight, 1% to 5% by weight, or 3% to 5% by weight.

[0037] Useful solvents include, for example, those used in lithium ion battery systems, such as ethylene carbonate, butylene carbonate, propylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, fluoroethylene carbonate, and mixtures thereof. Other useful solvents will be understood by those skilled in the art. Optionally, when an acidic species and a metal salt are dissolved in a solvent to form an electrolyte, the electrolyte itself exhibits acidic conditions (i.e., a pH of less than 7).

[0038] Examples of binders useful in the batteries and electrodes described herein include styrene butadiene copolymer (SBR), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), acrylonitrile, polyacrylic acid (PAA), polyvinyl alcohol (PVA), polyamideimide (PAI), and any combination thereof. Optionally, conductive polymers may be useful as binders.

[0039] Other examples of additives useful in the AMOs and electrodes described herein include, but are not limited to, conductive additives. Examples of conductive additives include graphite, conductive carbon, carbon black, Ketjen black, and conductive polymers such as poly(3,4-ethylenedioxythiophene (PEDOT), polystyrene sulfonate (PSS), PEDOT:PSS composites, polyaniline (PANI), and polypyrrole (PPY). The conductive additive may be present in the electrode in any suitable concentration, such as, for example, a weight percent of from greater than 0 to as much as 35 weight percent, 40 weight percent, or more. Optionally, the conductive additive may be present in the electrode in an amount of from 1 weight percent to 95 weight percent. The amount may be present in the ranges of 1% to 35% by weight, 1% to 25% by weight, 5% to 40% by weight, 10% to 40% by weight, 15% to 40% by weight, 20% to 40% by weight, 25% to 40% by weight, 30% to 40% by weight, 35% to 40% by weight, 40% to 45% by weight, 40% to 50% by weight, 40% to 55% by weight, 40% to 60% by weight, 40% to 65% by weight, 40% to 70% by weight, 40% to 75% by weight, 40% to 80% by weight, 40% to 85% by weight, 40% to 90% by weight, or 40% to 95% by weight.

[0040] Methods of making batteries are also described herein. An example of a method of making a battery includes making a metal oxide nanomaterial, forming a first electrode of or including a nanomaterial, forming an electrolyte by dissolving one or more metal salts in a solvent, and disposing the electrolyte between the first electrode and a second electrode. Another example of a method of making a battery includes making a metal oxide nanomaterial, forming a first electrode of or including a nanomaterial and one or more metal salts in a solvent, and disposing the electrolyte between the first electrode and a second electrode.

[0041] Also disclosed herein is an electrolyte for use in a battery. For example, the disclosed electrolyte is useful in a battery comprising a first electrode and a second electrode. An example of an electrolyte comprises a solvent and one or more metal salts dissolved in the solvent. Optionally, an acidic species, such as an acidic species different from the one or more metal salts, may be dissolved in the solvent.

[0042] As described above, a variety of acidic species are useful in the disclosed electrolytes, including acidic species including organic acids and / or organic acid anhydrides. Examples of organic acids include, but are not limited to, oxalic acid, acetic acid, citric acid, maleic acid, methylmalonic acid, glutaric acid, succinic acid, methylsuccinic acid, methylenesuccinic acid, citraconic acid, or any combination thereof. Examples of organic acid anhydrides include, but are not limited to, glutaric anhydride, succinic anhydride, methylsuccinic anhydride, maleic anhydride, itaconic anhydride, or any combination thereof. Examples of other acidic species are as described above. Useful acidic species include, but are not limited to, those exhibiting a pKa between -10 and 7, between -5 and 6, between 1 and 6, between 1.2 and 5.6, or about 4. The acidic species may optionally be present in the electrolyte at any suitable concentration, such as 0.01% to 10% by weight, 0.1% to 10% by weight, 1% to 5% by weight, or 3% to 5% by weight.

[0043] It will be understood that lithium metal salts such as LiPF6, LiAsF6, LiClO4, LiBF4, LiCF3SO3, etc., may be useful components of the disclosed acidified electrolyte. Examples of solvents include, but are not limited to, ethylene carbonate, butylene carbonate, propylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, fluoroethylene carbonate, and mixtures thereof. Examples of solvents may be useful in metal ion batteries, such as lithium ion batteries. [Brief description of the drawings]

[0044] [Figure 1] FIG. 1 is a simplified cross-sectional view of an exemplary lithium-ion battery cell. [Diagram 2] FIG. 2 is another simplified cross-sectional view of a lithium-ion battery cell in which the electrolyte is substantially contained by the separator. [Diagram 3] FIG. 1 is a schematic diagram of a lithium ion battery containing multiple cells. [Figure 4] 1 shows the difference in the cyclic voltammograms of AMO tin prepared by the methods disclosed herein compared to the cyclic voltammograms of commercially available non-AMO tin when cycled against Li. [Diagram 5] It is shown that the total reflectance of AMO tin oxide differs from that of commercial non-AMO tin oxide. [Figure 6] 1 is X-ray photoelectron spectroscopy (XPS) data showing surface functionalization that occurs intrinsically from the synthesis methods disclosed herein. The numbers shown are atomic concentrations in %. The rightmost column lists the corresponding pH of the synthesized nanoparticles measured when dispersed at 5 wt % in aqueous solution. [Figure 7] Electron microscopy images are provided showing the differences in morphology between AMO nanoparticles synthesized under identical conditions except for using different groups for functionalization. [Figure 8]FIG. 1 shows the differences in morphology and performance of AMO nanoparticles synthesized under identical conditions but with two different total reaction times. [Figure 9] Representative half-cell data are provided that show the difference in behavior towards lithium between spherical and elongated (needle-like or rod-like) AMOs upon cycling. [Figure 10] We provide X-ray photoelectron spectroscopy analysis of the surface of AMO nanoparticles synthesized using both strong (phosphorus-containing) and weak (acetate) electron-withdrawing groups, showing a higher atomic concentration of phosphorus than the bonds associated with acetate groups. [Figure 11A] Data are provided showing visible light activated degradation data of different AMOs. [Figure 11B] Data are provided showing the UV-activated degradation data of different AMOs. [Figure 12] 1 is a graph comparing two AMOs, one with higher capacity for use in primary (single use) battery applications and the other with higher cycling characteristics for use in secondary (rechargeable) battery applications. [Figure 13] Charge / discharge capacity data and coulombic efficiency data are provided, showing that AMO can enhance battery performance without degradation of battery components or gassing. [Figure 14] Capacity and cycling data for AMO in standard, acidified, and basified electrolyte systems are shown. [Figure 15] Capacity and cycle data for the AMO and the same AMO where the acidification was removed by solvent washing are shown. [Figure 16] 1 is a plot of temperature and voltage for a cell constructed in accordance with the present disclosure and subjected to a nail penetration test. [Figure 17A] 1 is a plot of temperature and voltage of a cell constructed in accordance with the present disclosure and subjected to overcharge testing. [Figure 17B] FIG. 17B is a plot of the overcharge test of FIG. 17A focusing on the start of the test. [Figure 18] FIG. 2 illustrates a side view of an exemplary cathode according to aspects of the present disclosure. [Figure 19]1 is a bar graph comparing the lithiation capacity of various metal oxides using standard construction techniques versus construction techniques according to the present disclosure. [Figure 20] 1 is a graph of voltage versus energy for MnO2 as an active material blended with various amounts of AMO tin oxide according to the present disclosure; [Figure 21] FIG. 1 is a cross-sectional side view of an alkaline AMO battery according to an embodiment of the present disclosure. [Figure 22] 1 is a graph comparing the discharge capacity of an alkaline cell containing the acidified SnO2 of the present disclosure blended with manganese dioxide to the discharge capacity of a conventional alkaline electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] definition For purposes of this disclosure, the following terms have the following meanings.

[0046] Acidic oxide - A term commonly used in the scientific literature to refer to binary compounds of nonmetallic elements with oxygen. An example is carbon dioxide, CO2. The oxides of some metalloids (e.g., Si, Te, Po) also have weakly acidic properties in the pure molecular state.

[0047] Acidified Metal Oxide ("AMO") - a term used herein to mean a binary compound of a metal element and oxygen, which has been synthesized or modified to have a higher acidity than that of its natural mineralogical state, and a Hammett function, H0>-12 (not super acidic), and an average particle size smaller than that of the natural mineralogical state. Naturally occurring mineralogical forms are not included within the scope of the AMO materials of the present invention. However, synthetic metal oxides that are more acidic than the most abundant naturally occurring (equivalent stoichiometric) mineralogical forms, but are not super acidic, are included within the scope of the present disclosure and may be said to be AMO materials if they meet certain other conditions discussed in this disclosure.

[0048] Acidic - A term commonly used in the scientific literature to refer to compounds that have a pH of less than 7 in aqueous solution.

[0049] Electron Withdrawing Group ("EWG") - an atomic or molecular group that attracts electron density to itself. The strength of an EWG is based on its known behavior in chemical reactions. For example, halogens are known to be strong EWGs. Organic acid groups such as acetate are known to be weakly electron withdrawing.

[0050] Hammett function - an additional means of quantifying acidity in concentrated acid solutions and superacids, where acidity is defined by the following equation: H0=pK BH+ +log([B] / [BH + On this scale, 18.4 moles of pure H2SO4 has an H0 value of -12. The value of H0=-12 for pure sulfuric acid should not be interpreted as a pH=-12, but rather it indicates that the species of acid present has a pH of 10 as measured by its ability to protonate weak bases. 12 H3O in a hypothetical (ideal) concentration in mol / L + This means that the acidity function has a protonation ability equivalent to that of the superacids. The Hammett acidity function avoids water in its equation. It is used herein to provide a quantitative means of distinguishing between AMO materials and superacids. The Hammett function can be correlated with colorimetric reagent tests and temperature programmed desorption results.

[0051] Layered Structure - As used herein, the term "layered structure" refers to a battery cell that is composed of separate material deposits (which may or may not be of the same material) with at least one interface between them. Interfaces may be present during construction, but are effectively reduced or eliminated in the final product, as specified herein.

[0052] Low Loading - active material or a mixed layer containing active material, where the active material is present in an amount ranging from 10% to 80% by weight.

[0053] Metal oxide - a term commonly used in academic literature to refer to binary compounds of metallic elements and oxygen. Depending on their position in the periodic table, metal oxides range from weakly basic to amphoteric (exhibiting both acidic and basic properties) in their pure molecular state. Weakly basic metal oxides are the oxides of lithium, sodium, magnesium, potassium, calcium, rubidium, strontium, indium, cesium, barium and tellurium. Amphoteric oxides are the oxides of beryllium, aluminum, gallium, germanium, astatine, tin, antimony, lead and bismuth.

[0054] Monodisperse--characterized by particles of uniform size that are substantially separate from one another and not agglomerated into grains of larger particles.

[0055] pH - a numerical scale of functions commonly used in scientific literature to specify the acidity or alkalinity of an aqueous solution. It is the function of the hydronium ion [H3O +

[0046] As used herein, it describes the relative acidity of nanoparticles suspended in an aqueous solution.

[0056] Surface functionalization - The attachment of small atomic or molecular groups to the surface of a material.

[0057] Superacid - A substance that is more acidic than 100% H2SO4 and has a Hammett function of H0<-12. Detailed Description of the Preferred Embodiments Described herein are high capacity electrochemical cells and cell components such as electrodes for such cells. The disclosed electrochemical cells and electrodes include metal oxides, which may be AMO or non-AMO nanomaterials, and exhibit high capacity. In embodiments, the metal oxides are provided at relatively low loadings (weight percent) in the electrode, such as less than 30% weight percent, with the majority of the remainder of the electrode including conductive materials and binders. Even at such low loadings, capacities of over 10,000 mAh / g have been observed for AMO nanomaterials. The electrodes may be provided in layered or non-layered configurations. Examples of layered configurations include separate layers including AMO nanomaterials, and low loading or non-AMO containing layers. In other embodiments, non-AMO metal oxides may be layered with other non-AMO metal oxides of the same or different materials. In further embodiments, layers may include both AMO and non-AMO metal oxides within the same layered structure. However, layering of the electrodes is optional, and high capacity has been observed in both layered and non-layered electrodes.

[0058] Referring now to FIG. 1, a lithium-ion battery cell 100 is shown in a simplified cross-sectional view. The cell 100 may include a casing or container 102. In some embodiments, the casing 102 is a polymer or alloy. The casing 102 chemically and electrically isolates the contents of the cell 100 from adjacent cells, from contamination, and from damage or from other components of the device in which the cell 100 is installed. A complete battery may include multiple cells arranged in series and / or parallel configurations. The battery may have additional casings or fastening mechanisms that join multiple cells together, as known in the art.

[0059] The cell 100 provides a cathode 104 and an anode 106. The contents of the cell 100 undergo a chemical reaction when a conductive path is provided between the cathode 104 and the anode 106 that is external to the cell 100. As a result of the chemical reaction, electrons are provided at the anode 106, and these electrons flow to the cathode 104 through a circuit (sometimes called a load) that is external to the battery. At a basic level, during discharge of the cell 100, the materials that comprise the anode 106 are oxidized, providing the electrons that flow through the circuit. As a recipient of the electrons released by the anode 106, the materials that comprise the cathode 104 are reduced.

[0060] In the cell 100, during discharge, metal cations migrate through the electrolyte 108 from the anode 106 to the cathode 104. In the case of lithium-based batteries, the metal cations are lithium cations (Li + ) The electrolyte 108 can be a liquid electrolyte, such as a lithium salt in an organic solvent (e.g., LiClO4 in ethylene carbonate). Other lithium-based electrolyte / solvent combinations known in the art may be used. In some cases, the electrolyte 108 can be a solid electrolyte, such as a lithium salt in polyethylene oxide. Optionally, the electrolyte may include a polymer electrolyte. Examples of electrolytes include those described in U.S. Patent Application Publication No. 2017 / 0069931, which is incorporated herein by reference.

[0061] A separator 110 may be used to prevent contact between the electrodes 104, 106. The separator 110 may be a porous layer material that is permeable to lithium ions and the electrolyte 108, but is not otherwise conductive, to prevent internal shorting of the cell 100. As is known in the art, the separator 110 may include glass fibers or optionally a polymer having a semi-crystalline structure. Additional components, such as current collectors, may also be included in the cell 100, but are not shown in FIG. 1.

[0062] Together, the anode 104, cathode 106, electrolyte 108, and separator 110 form the complete cell 100. Because the separator 110 is porous, the electrolyte 108 can flow into or be contained within the separator 110. Under normal operating conditions, the porosity of the separator 110 allows the ions (Li + ) is allowed to flow between the electrodes 104, 106 via the electrolyte 108. As is known in the art, the separator can be constructed such that if exposed to an excess of heat or a runaway exothermic reaction, the internal pore structure will melt and close, shutting down the cell.

[0063] Most lithium-based batteries are so-called secondary batteries. Secondary batteries can be discharged and recharged many times until the chemical or structural integrity of the cell falls below acceptable limits. Cells and batteries according to the present disclosure are considered to be both primary (e.g., single-use) and secondary batteries.

[0064] In the case of cell 100 being a secondary battery (or part of a secondary battery), it should be understood that cell 100 may be recharged alone or as a component of a complete system in which multiple cells are recharged simultaneously (and possibly in the same parallel or series circuit).

[0065] To effect charging, a reverse voltage is applied to the cell 100. It should be understood that various schemes for effectively recharging a lithium battery can be used. Constant current, variable current, constant voltage, variable voltage, partial duty cycle, etc. may be used. This disclosure is not intended to be limited to any particular charging method unless otherwise stated in the claims. During charging of the cell 100, element 115 represents a voltage source that is applied between the cathode 104 and the anode 106 to provide electrons from the cathode 105 to the anode 106, allowing a chemical reaction to occur. Lithium ions fold back from the cathode 104 to the anode 106 through the electrolyte 108 and the separator 110.

[0066] As an example, the cathode 104 or anode 106 may independently comprise a metal oxide in accordance with the present disclosure. The metal oxide may be a nanomaterial, possibly substantially monodisperse, and in either AMO or non-AMO form. When an AMO material is used as the cathode, the anode may correspond to lithium metal or a lithium intercalation material, such as graphite. A non-AMO cathode may also be paired with an anode that may correspond to lithium metal or a lithium intercalation material. Optionally, the electrolyte 108 may include an acidic species dissolved in an organic solvent along with a lithium salt. In addition to or as an alternative to the use of an acidic species in the electrolyte 108, the electrode (i.e., the cathode 104 or anode 106) may optionally include an AMO and an acidic species. Oxalic acid is an exemplary acidic species.

[0067] Without wishing to be bound by any theory, it is believed that the presence of acidic species in the cathode 104 or anode 106 and / or electrolyte 108 improves the surface affinity of the AMO material for lithium ions, which in turn improves its ability to absorb lithium ions during discharge, resulting in an overall improved capacity compared to a similar cell lacking acidic species or having a basified electrode or electrolyte (i.e., including basic species). Alternatively, or in addition, the presence of acidic species may allow additional active sites for lithium absorption at the cathode 104.

[0068] It should be understood that FIG. 1 is not to scale. As shown in FIG. 2, in most applications, the separator 110 occupies most or all of the space between and is in contact with the electrodes 104, 106. In such cases, the electrolyte 108 is contained within the separator 110 (although it may also penetrate into the pores or surfaces of the anode or cathode). FIG. 2 is also not necessarily to scale. The actual geometry of the cell can range from a relatively thin, flat pouch to a canister-type structure, button cell, and the like. Cell construction techniques such as wound or bobbin-type or pin-type assemblies may be used.

[0069] Current collectors and other components (not shown) known in the art can also be included to form the cell 100 into a commercially usable package. Although the overall shape or geometry may vary, a cell or battery typically includes electrodes 104, 106 that are separated rather than touching at some location or cross-section, with an electrolyte 108 and optionally a separator 110 between the electrodes 104, 106. Cells may also be constructed such that there are multiple layers of anodes and cathodes. Cells may also be configured such that two cathodes are on opposite sides of a single anode, or vice versa.

[0070] A functional or operable battery intended for a particular purpose may comprise multiple cells arranged according to the needs of a particular application. An example of such a battery is shown diagrammatically in FIG. 3, where the battery 300 includes four lithium cells 100 arranged in series to increase the voltage. The capacity can be increased at this voltage by providing an additional stack of four cells 100 in parallel with the stack shown. Different voltages can be achieved by varying the number of cells 100 arranged in series.

[0071] The positive electrode 306 may be accessible outside the casing 302 of the battery 300. A negative electrode 304 is also provided. The physical form factor of the electrodes 304, 306 may vary depending on the application. Various binders, adhesives, tapes, and / or other fastening mechanisms (not shown) may be used within the battery casing 302 to stabilize the other components. Batteries based on lithium technology are generally operable, rechargeable, and storable (if secondary) in either orientation. As noted above, the cell 100 may take on a variety of different geometric shapes. Thus, FIG. 3 is not intended to represent a particular physical form factor of the battery 300.

[0072] The battery 300 may also include various auxiliary circuits 308 disposed within the casing 302 of the battery 300 between the positive terminal 308 and the lithium cell 100. In other embodiments, the auxiliary circuits are disposed between the negative terminal 304 and the lithium battery 100 instead of, or in addition to, being disposed between the positive terminal 306 and the lithium battery 100. The auxiliary circuits 308 may include short circuit protection, overcharge protection, overtemperature shutdown, and other circuits known in the art for protecting the battery 300, the cells 100, and / or any load attached to the battery 300.

[0073] The composition of materials selected for the cathode 104, anode 106, and electrolyte can be important to the performance of the cell 100 and any battery of which it forms a part. In the context of the present disclosure, various examples of AMOs and their methods of manufacture are provided in this regard. These AMOs are suitable for use in forming anodes or cathodes in half cells, cells, and batteries. The AMOs of the present disclosure are otherwise compatible with known lithium cell technology, including existing anode compositions, cathode compositions, electrolyte formulations, and separator compositions. Other embodiments may employ the same or different manufacturing, construction, or formation methods utilized for AMOs, but use non-AMO materials.

[0074] It will be appreciated that the anode 106 material selected for a cell or battery according to the present disclosure will be less electronegative than the material of the cathode 104 and may suitably complement the cathode material. In one particular embodiment, the disclosed AMOs are useful as cathodes in cells having metallic lithium anodes.

[0075] In various embodiments of the present disclosure, the cathode 104 comprises an AMO material having an acidic, but not super acidic, surface. This may be in contrast to materials previously known and utilized as cathodes, such as lithium cobalt or lithium manganese materials. The AMO materials of the present disclosure and their methods of manufacture are described below. In other embodiments, the anode 106 comprises an AMO material of the present disclosure having an acidic, but not super acidic, surface.

[0076] Metal oxide surfaces are ideally arrays of metal and oxygen centers, aligned according to the oxide's crystal structure. In reality, the array is imperfect and prone to vacancies, distortions, and surface deposits. Regardless, all exposed metal centers are cationic (positively charged) and can accept electrons, and therefore function as Lewis acid sites by definition. The oxygen centers are anionic (negatively charged) and act as Lewis basic sites that donate electrons. This gives rise to the familiar amphoteric nature of metal oxide surfaces.

[0077] Under normal atmospheric conditions, water vapor present will adsorb on the surface of metal oxides either in molecular form (hydrated) or in dissociated form (hydroxylated). OH - Seed and H + Both species can be adsorbed on the oxide surface. The negatively charged hydroxyl species binds to the cationic (Lewis acid, electron accepting) center of the metal and forms H + binds to the anion (Lewis base, electron donating) center of oxygen. Both adsorptions result in the presence of the same functional group - hydroxyl - on the metal oxide surface.

[0078] These surface hydroxyl groups can either give up or accept a proton and therefore can function as either Bronsted acids or Bronsted bases. The tendency of an individual hydroxyl group to be a proton donor or acceptor is influenced by the coordination of the metal cation or oxygen anion to which it is bound. Metal oxide surface defects such as oxygen vacancies, or coordination to surface groups by other species, mean that not all cations and anions are coordinated equally. Acid and base sites vary in number and strength. When "aggregated" broadly across the surface of an oxide, this can give the surface an overall acidic or basic character.

[0079] The amount and strength of Lewis acid and base sites (from exposed metal cations and oxygen anions, respectively) and Brønsted acid and base sites (from surface hydroxyl groups) add a wide range of utility and functionality to metal oxides and their use in both chemical reactions and device applications. These sites contribute significantly to the chemical reactivity of metal oxides. They can function as anchor points to which other chemical groups, even additional metal oxides, can be attached. They can also affect surface charge, hydrophilicity, and biocompatibility.

[0080] One way to modify the surface of metal oxides is to attach small chemical groups or electron-withdrawing groups ("EWGs") in a process known as surface functionalization. The EWG induces polarization of the hydroxide bond, promoting dissociation of hydrogen. For example, a stronger EWG should result in a more polarized bond, which in turn should result in more acidic protons. The acidity of a Lewis point can be increased by inducing a polarization that promotes the donation of electrons to the point. If the compound so made is placed in water, the acidic protons will dissociate, thus lowering the pH reading of the water.

[0081] Although somewhat imprecise when working with solid rather than liquid acid / base systems, traditional pH measurement methods utilizing titration, pH paper, and pH probes can be used to assess the acidity of metal oxides dispersed in aqueous solutions. These measurements can be supplemented using techniques including, but not limited to, colorimetric reagents, infrared spectroscopy, and temperature programmed desorption data to establish the acidified nature of the metal oxide surface. Surface groups can be examined by standard analytical techniques including, but not limited to, X-ray photoelectron spectroscopy.

[0082] Surface functionalization can be accomplished post-synthesis, including but not limited to exposing the metal oxide to an acidic solution or to a vapor containing the desired functional group. It can also be accomplished by solid-phase methods, in which the metal oxide is mixed and / or ground with a solid containing the desired functional group. However, all of these methods require one or more additional surface functionalization steps beyond those required to synthesize the metal oxide itself.

[0083] The synthesis and surface functionalization of the AMO material may be accomplished by a "single-pot" hydrothermal synthesis method or equivalent, where the surface of the metal oxide is functionalized as it is synthesized from the appropriate precursor. The salt of the precursor containing the EWG is solubilized, and the resulting solution is acidified with an acid containing a second EWG. The acidified solution is basified, and the basified solution is heated and then washed. A drying step produces the solid AMO material.

[0084] As an example, a preferred embodiment of tin oxide in the AMO form was synthesized and simultaneously surface functionalized using the following single-pot method.

[0085] 1. First, seven grams (7 g) of tin(II) chloride dihydrate (SnCl2·2H2O) is dissolved in a solution of 35 mL of absolute ethanol and 77 mL of distilled water.

[0086] 2. Stir the resulting solution for 30 minutes.

[0087] The solution is acidified by dropwise addition of 3.7 mL of 1.2 M HCl and the resulting solution is stirred for 15 min.

[0088] The solution is basified by dropwise addition of 4.1 M aqueous base until the pH of the solution is approximately 8.5.

[0089] 5. The resulting opaque white suspension is then placed in a water bath (approximately 60-90°C) with stirring for at least 2 hours.

[0090] 6. The suspension is then washed with distilled water and absolute ethanol.

[0091] 7. The washed suspension is dried in air at 100° C. for 1 hour and then annealed in air at 200° C. for 4 hours. This method yields tin AMOs surface-functionalized with chlorine, whose pH is about 2 when measured by resuspension at room temperature in aqueous solution at 5 wt %. By definition, their Hammett function is H>-12. Although an open system such as a flask is described here, closed systems such as an autoclave may also be used.

[0092] Using the single-pot method disclosed above, several AMOs have been synthesized. Table 1 below describes the precursors and acids used. In some cases, dopants are utilized as well:

[0093] [Table 1] In some embodiments, the electron withdrawing group has a carbon chain length of 6 or less and / or an organic mass (AMU) of 200 or less. In some embodiments, the electron withdrawing group has a carbon chain length of 8 or less or 10 or less and / or an organic mass of 500 or less.

[0094] It will be understood that the parameters of this method can be varied. These parameters include, but are not limited to, the type and concentration of reagents, the type and concentration of acid and base, reaction time, temperature and pressure, agitation speed and time, number and type of washing steps, drying and calcination time and temperature, and exposure to gas during drying and calcination. Variations may be performed alone or in any combination, possibly using experimental design techniques. Additionally, other metal oxide synthesis methods, such as spray pyrolysis, vapor deposition, electrodeposition, solid-state methods, and hydrothermal or solvothermal processes, may be useful to achieve the same or similar results as the methods disclosed herein.

[0095] A variety of annealing conditions are useful for the preparation of AMO nanomaterials. Exemplary annealing temperatures can be below 300°C, e.g., 100°C to 300°C. Exemplary annealing times can range from about 1 hour to about 8 hours or more. Annealing can be performed under a variety of atmospheric conditions. For example, annealing can be performed in air at atmospheric pressure. Annealing can be performed under high pressure (higher than atmospheric pressure) or under reduced pressure (lower than atmospheric pressure or in a vacuum). Alternatively, annealing can be performed in a controlled atmosphere, such as under an inert gas (e.g., nitrogen, helium, or argon) or in the presence of an oxidizing gas (e.g., oxygen or water).

[0096] A variety of drying conditions are useful for the preparation of AMO nanomaterials. Exemplary drying temperatures can be from 50° C. to 150° C. Exemplary drying times can range from about 0.5 hours to about 8 hours or more. Drying can be performed under a variety of atmospheric conditions. For example, drying can be performed in air at atmospheric pressure. Drying can be performed under high pressure (higher than atmospheric pressure) or under reduced pressure (lower than atmospheric pressure or in a vacuum). Alternatively, drying can be performed in a controlled atmosphere, such as under an inert gas (e.g., nitrogen, helium, or argon) or in the presence of an oxidizing gas (e.g., oxygen or water).

[0097] The performance characteristics of the disclosed AMO nanomaterials are different from those of non-acidified metal oxide nanoparticles. As an example, FIG. 4 shows the difference in the cyclic voltammograms of AMO tin prepared by a single-pot method compared to that of commercially available non-AMO tin when cycled against lithium. For example, the surface-functionalized AMO material shows better reversibility than the non-AMO material. The presence of distinct peaks in the CV of the AMO material may indicate that multiple electron transfer steps are occurring during charge / discharge. For example, the high voltage peaks may indicate direct oxidation / reduction of the AMO material, while the low voltage peaks may be due to changes in the material structure of the AMO material (i.e., alloying).

[0098] As another example, Figure 5 shows that the total reflectance of AMO tin oxide differs from that of commercially available non-AMO tin oxide. The data indicates that AMO has a lower bandgap and therefore more desirable properties as a component of a photovoltaic system in addition to its use as an anode according to the present disclosure.

[0099] AMO materials have the general formula M m O x / G (In the formula, M m O x is a metal oxide, m is 1 or more and 5 or less, and x is 1 or more and 21 or less; G is at least one EWG that is not a hydroxide; ( / simply makes a distinction between metal oxides and EWG, and does not imply a fixed numerical relationship or ratio between the two.) It can be thought of as having the following. G may represent a single type of EWG, or it may represent two or more types of EWG.

[0100] An exemplary AMO is acidified tin oxide (Sn x O y ), acidified titanium dioxide (Ti a O b ), acidified iron oxide (Fec O d ), and acidified zirconium oxide (Zr e O f ). Exemplary electron withdrawing groups ("EWGs") are Cl, Br, BO3, SO4, PO4, and CH3COO. In accordance with the present disclosure, regardless of the particular metal or EWG, the AMO materials are acidic, but not superacidic, having a pH<7 when suspended at 5 wt % in aqueous solution, and having a Hammett function of H0>-12, at least on their surface.

[0101] The AMO materials may be crystalline or amorphous in structure (or combinations thereof) and may be utilized alone or in combination with each other as composites, with non-acidified metal oxides, or with other additives, binders, or conductive aids known in the art. In other words, anodes made utilizing the AMOs of the present disclosure may or may not include other materials. In one embodiment, the AMO may be layered onto a conductive material to form the cathode 104. In some embodiments, the AMO material may be added to a conductive aid such as graphite or conductive carbon (or their equivalents) in the range of 10% to 80% by weight and in the range of greater than 90% to 95% by weight. In preferred embodiments, the AMO is added at 10%, 33%, 50%, and 80% by weight.

[0102] To maximize the amount of total available surface area, the AMO should be in nanoparticulate form (i.e., less than 1 micron in size) and substantially monodisperse. More preferably, the nanoparticulate size is less than 100 nm, and even more preferably less than 20 nm or less than 10 nm. In other embodiments utilizing non-AMO metal oxides, the material may still be in nanoparticle form and substantially monodisperse. Again, the nanoparticle size may be less than 100 nm, and preferably less than 20 nm or less than 10 nm.

[0103] In mixed metal AMOs, another metal or metal oxide is present in addition to the single or binary oxide, and these mixed metal AMOs have been implemented in forming anodes for use in half-cells, cells, and batteries. These mixed metal AMOs have the general formula M m N n O x / G and M m N n R r O x / G (In the formula, M is a metal and m is greater than or equal to 1 and less than or equal to 5; N is a metal, n is greater than zero and is equal to or less than 5; R is a metal and r is greater than zero and less than or equal to 5; O is the total oxygen associated with all metals, and x is greater than or equal to 1, and less than or equal to 21; / simply makes a distinction between metal oxides and electron-withdrawing surface groups, and does not imply a fixed numerical relationship or ratio between the two; G is at least one EWG that is not a hydroxide It can be thought of as having the following. G may represent a single type of EWG, or it may represent two or more types of EWG.

[0104] Although some prior art mixed metal oxide systems, of which zeolites are the most prominent example, exhibit strong acidity, each single oxide does not. Preferred embodiments of the mixed metal AMOs of the present disclosure are those in which no single M oxide is present in any embodiment. m O x The mixed metal oxide systems differ from the prior art in that they must contain at least one AMO that is acidic (not super acidic) in the / G form. The preferred mixed metal and metal oxide systems are Sn x Fe c O y+d and Sn x Ti a O y+b where y+d and y+b may be integer or non-integer values.

[0105] In another embodiment, mixed metal AMO materials are prepared by a single-pot method with one modification, i.e., the synthesis begins with salts of two metal precursors in any ratio instead of one. For example, step 1 of the single-pot method may be modified as follows: first, 3.8 g of tin(II) chloride dihydrate (SnCl2·2H2O) and 0.2 g of lithium chloride (LiCl) are dissolved in a solution of 20 mL of absolute ethanol and 44 mL of distilled water.

[0106] The metal precursor salts shown in Table 1 can be used in any proportion. The metal precursor salts can have the same anionic group or different anionic groups, depending on the desired product, can be introduced at different times during the synthesis, or can be introduced as a solid or in a solvent. In some embodiments, a first metal precursor salt can be used in the primary structure (i.e., a larger proportion) of the resulting AMO, and a second (and optionally a third) metal precursor salt can be added as a dopant or as a minor component of the resulting AMO.

[0107] Experiments with the single-pot method led to seven notable findings. First, in all cases, both surface functionalization and acidity arise endogenously rather than post-synthetically (see FIG. 6). Unlike prior art surface functionalization methods, the single-pot method does not require any additional step or steps for surface functionalization beyond those required to synthesize the metal oxide itself, nor does it utilize hydroxyl-containing organic compounds or hydrogen peroxide.

[0108] Second, the method can be broadly generalized across a wide range of metal oxides and EWGs. Using the method disclosed herein, metal oxides of iron, tin, antimony, bismuth, titanium, zirconium, manganese, and indium were synthesized and simultaneously surface-functionalized with chloride, sulfate, acetate, nitrate, phosphate, citrate, oxalate, borate, and bromide. Mixed-metal AMOs of tin and iron, tin and manganese, tin and manganese and iron, tin and titanium, indium and tin, antimony and tin, aluminum and tin, lithium and iron, and lithium and tin were also synthesized. In addition, surface functionalization can be achieved with EWGs that are weaker than halogens and SO4, which still produce surfaces that are acidic but not superacidic. For example, the method was also used to synthesize AMOs surface-functionalized with acetate (CH3COO), oxalate (C2O4), and citrate (C6H5O7). Various embodiments are described below.

[0109] Third, there is a synergistic relationship between EWG and other properties of the nanoparticles, such as size, morphology (e.g., plate-like, spherical, needle-like, or rod-like), oxidation state, and crystallinity (amorphous, crystalline, or a mixture of these). For example, morphology differences can occur between AMO nanoparticles synthesized under identical conditions except for the use of different EWGs for surface functionalization (see FIG. 7). Surface functionalization can act to "freeze" the dimensions of the nanoparticles, halting their growth. This freezing effect may occur in only one dimension of the nanoparticles, or in two or more dimensions, depending on the exact synthesis conditions.

[0110] Fourth, the properties of AMOs are highly sensitive to the synthesis conditions and procedures. For example, differences in the morphology and performance of AMO nanoparticles can occur when synthesized under identical conditions but with two different total reaction times (see Figures 8 and 9). Experimental design approaches can be used to determine the best or optimal synthesis conditions and procedures, which result in a desired property or combination of properties.

[0111] Fifth, both the anions present in the salt of the precursor and the anions present in the acid contribute to the surface functionalization of the AMO. In a preferred embodiment, a tin chloride precursor and hydrochloric acid are used to synthesize the tin AMO. The performance of these particles is different from the embodiment using a tin chloride precursor and sulfuric acid or the embodiment using a tin sulfate precursor and hydrochloric acid. Therefore, in some embodiments, it is preferred to match the anions of the precursor and the acid.

[0112] Sixth, when utilizing a precursor with a weak EWG and an acid with a strong EWG, or vice versa, the anion with the stronger attraction will dominate the surface functionalization. This opens up a wider range of synthetic possibilities, allowing functionalization with ions that are not readily available in both the precursor salt and the acid. There is also the possibility of mixed functionalization with both strong and weak EWGs. In one example, tin AMOs are synthesized using tin acetate precursors and phosphoric acid. X-ray photoelectron spectroscopy analysis of the surface shows a higher atomic concentration of phosphorus than the bonds associated with the acetate groups (see Figure 10).

[0113] Seventh, and finally, while the disclosed method is a general procedure for the synthesis of AMOs, the synthesis procedure and conditions may be tailored to obtain sizes, morphologies, oxidation states, and crystal states that may be desirable for various applications. As an example, catalytic applications may require AMO materials that are more active in visible light (see FIG. 11A) or more active in ultraviolet light (see FIG. 11B).

[0114] In another example, AMO materials may be used as battery electrodes. A primary (single-use) battery application may require an AMO with properties that provide the highest capacity, while a secondary (rechargeable) battery application may require the same AMO but with properties that provide the best cycling characteristics. Figure 12 compares the cycling characteristics of two different batteries constructed with AMO materials, including a chlorine-containing AMO and a sulfur-containing AMO. AMO materials can improve battery performance without degradation of battery components or gassing (see Figure 13). This is the opposite of what the prior art teaches.

[0115] The cycling characteristics of the battery constructed as an AMO nanomaterial electrode vs. lithium metal half cell are shown in Figure 13, which shows cycling characteristics up to 900 charge / discharge cycles while maintaining useful capacity and exceptional coulombic efficiency. Such long cycling characteristics are particularly remarkable for a lithium metal reference electrode, since lithium metal is known to grow dendrites even at low cycle counts, leading to dendrite expansion and potentially dangerous and catastrophic battery cell failure.

[0116] In accordance with the present disclosure, in a complete cell, an anode 106 including the disclosed AMOs can be utilized with a known electrolyte 108 and a cathode 104 including known materials, such as lithium cobalt oxide (LiCoO2). Similarly, the materials including the separator 110 can be drawn from those currently known in the art. In another embodiment, the anode 106 may include the disclosed non-AMO metal oxides with a known electrolyte 108, and the cathode 104 includes known materials and / or is constructed according to known methods.

[0117] In a complete cell, a cathode 104 including the disclosed AMO can be utilized with a known electrolyte 108 and an anode 106 including known materials, such as carbon on copper foil, that exhibit lower electronegativity than that of the disclosed AMO. Similarly, the materials including the separator 110 and electrolyte 108 can be drawn from those currently known in the art, as discussed above. In another embodiment, the cathode 104 may include a disclosed non-AMO metal oxide with a known electrolyte 108, and the anode 106 includes known materials and / or is constructed according to known methods.

[0118] Various layering and other strengthening techniques may be deployed to maximize the ability to retain lithium ions to power the cell 100. It should also be understood that batteries according to the present disclosure can be deployed as secondary (e.g., rechargeable) batteries, but can also function as primary batteries. Although the anodes and cathodes of the present disclosure are suitable for reversible battery chemistries, cells or batteries constructed as described herein may well be deployed as primary cells or batteries.

[0119] In the battery industry, the term "formation" is used to indicate the initial charging or discharging of a battery that occurs at a manufacturing facility before the battery is ready for use. The formation process is generally very slow and may require multiple cycles directed at converting the as-produced active material into a form more accessible to the cell cycle. These transformations may be modifications of the structure, morphology, crystallinity, and / or stoichiometry of the active material.

[0120] Cells and batteries constructed according to the present disclosure, in some embodiments, do not require initial formation and therefore can be used immediately as primary cells or batteries. In other cases, limited formation or rapid formation may be used. Furthermore, by deploying the cells and batteries of the present disclosure as primary batteries that are not intended to be recharged, some of the safety issues that are known in the art to arise more frequently during battery cycling, but that are believed to be inherent to lithium battery chemistry, are mitigated. However, after the initial primary discharge, the cells and batteries disclosed herein are suitable for use as secondary battery systems that may optionally undergo many charge / discharge cycles, such as up to tens, hundreds, or even thousands of cycles.

[0121] In other embodiments according to the present disclosure, the cathode 104 includes nanoparticles of non-AMO tin oxide (SnO2). The tin oxide nanoparticles may be substantially monodisperse. According to embodiments of the present disclosure, titanium dioxide (TiO2), iron oxide (FeO, Fe2O3, Fe3O4), or another metal oxide may be substituted for the tin oxide. Known electrolytes 108, anodes 106, and separators 110, or those otherwise described in this disclosure, may be utilized in such embodiments.

[0122] It will be understood that other battery structures are possible using the AMO and non-AMO metal oxides of the present disclosure. For example, a battery can include a first electrode comprising the metal oxide of the present disclosure (possibly in monodisperse nanoparticle form), a second electrode, and an electrolyte disposed between the first and second electrodes. As an example, in a lithium-ion battery, the first electrode may operate as a cathode or an anode. For example, in operation as a cathode, the second electrode may correspond to lithium metal, graphite, or another anode material. As another example, in operation as an anode, the second electrode may correspond to LiCoO2, LiMn2O4, LiNiO2, or another cathode material. Materials useful for the second electrode include, but are not limited to, graphite, lithium metal, sodium metal, lithium cobalt oxide, lithium titanate, lithium manganese oxide, lithium nickel manganese cobalt oxide (NMC), lithium iron phosphate, lithium nickel cobalt aluminum oxide (NCA), or any combination thereof.

[0123] It will be appreciated that the AMO materials disclosed herein may be added as dopants to the anode and / or cathode of a conventional lithium ion cell in amounts between 0.01% and 10% by weight of the AMO material in the electrode, or, for example, in amounts of about 1%, 5% or 10% by weight. The disclosed AMO materials provide a surprising capacity to store lithium atoms, and adding these materials to conventional lithium ion cell electrodes provides these composite capabilities. In one particular example, the electrode includes LiCoO2 and AMO. In another example, the electrode includes a carbonaceous material, such as graphite, and AMO.

[0124] The metal oxides of the present disclosure may be used with optional acidic components such as binders, acidic electrolytes, or acidic electrolyte additives. The AMO materials of the present disclosure may be in the context of an anode, cathode, half cell, complete cell, integrated battery, or other components. The inventors have surprisingly found that including an acidic component and / or acidic species, such as an organic acid or anhydride, in a battery containing an AMO material increases capacity compared to a battery without the acidic species. Again, the prior art teaches against the use of acidic species, as these species can degrade metal current collectors and housings and cause degradation of other electrode components.

[0125] As shown in FIG. 14, comparative data on the cycling characteristics of AMO-based batteries formed with the same materials and structure except with standard electrolyte, basified electrolyte, and acidified electrolyte are provided. The batteries included the following structures: all cathodes included the same AMO material; all anodes were lithium metal; the standard electrolyte was a 1:1:1 mixture of dimethyl carbonate, diethylene carbonate, and ethylene carbonate with 1M LiPF6; the acidified electrolyte was a standard electrolyte with 3 wt% succinic anhydride; the basified electrolyte was a standard electrolyte with 3 wt% dimethylacetamide. All batteries were cycled at the same discharge rate. As shown, the battery with the acidified electrolyte system exhibited the best cycling capability and maintained the highest capacity even beyond the maximum number of cycles.

[0126] FIG. 15 provides additional comparative cycling performance data for two different batteries with the same cell configuration except that one battery contained an acidified electrolyte and the AMO material in one battery was de-acidified by washing with a solvent. The batteries contained the following configuration: the cathode contained the AMO material; the electrolyte was a 1:1:1 mixture of dimethylene carbonate, diethylene carbonate, and ethylene carbonate with 1 M LiPF6 and 3 wt. % succinic anhydride; the anode was lithium metal. The batteries were cycled at the same discharge rate. The battery with the acidified AMO material showed higher capacity retention over cycle number, indicating that the acidified surface of the AMO interacts with the acidified electrolyte, enhancing performance.

[0127] Currently, lithium batteries are recognized as a safety risk in certain circumstances. For example, airline regulations now require partial discharge of lithium batteries carried in cargo holds. Fires resulting from runaway exothermic reactions have been reported in devices using lithium batteries. Furthermore, lithium fires can be difficult to extinguish with commonly deployed fire suppression systems and equipment. For these reasons, lithium-containing compounds, rather than metallic lithium, are used in many commercial battery cells.

[0128] However, using lithium-containing compounds in the anode rather than lithium metal may limit the amount of lithium available to react and absorb into the cathode during discharge, and therefore may limit the capacity of such cells. However, the AMO materials disclosed herein not only absorb more lithium during discharge, but also show improved safety characteristics. For example, when battery cells containing AMO materials in the cathode and lithium metal electrodes are subjected to safety tests such as nail penetration tests, short circuit tests, and overvoltage tests, the batteries perform well and do not appear to pose an unacceptable risk of fire or explosion. This may be because the AMO passivates the lithium metal in the cell or battery. Even with the use of solid or pure lithium as the anode, devices using the AMO of the present disclosure as the cathode do not appear to pose an unacceptable risk of fire or explosion. The novel safety results may also be due to the lower operating voltage of cells constructed according to the present disclosure, which in some embodiments is <1.5V compared to conventional lithium-ion operating voltages >3.0V.

[0129] Several cells were constructed with a cathode comprising AMO(SnO2) according to the present disclosure. The cathode was prepared from a composition of AMO(SnO2), Ketjen Black (KB), polyvinylidene fluoride (PVDF), and polyarylamide (PAA) in a volume ratio of 63 / 10 / 26.1 / 0.9. Double-sided layers of this composition were applied at 4 mg / cm2 per side. 2 Six of these layers constituted the cathode. The area of ​​the prepared cathode was 9 × 4 cm 2 The separator was obtained from Targray Technology International, Inc. and contained a 25 μm thick layer of polypropylene. The separator area was 9.4 × 4.4 cm 2 The electrolyte was prepared from 1 M LiPF6 in a solvent of ethylene carbonate, diethyl carbonate, and dimethyl carbonate in a 1 / 1 / 1 volume ratio. The anode had an area of ​​9.2 × 4.2 cm 2 , a 50 μm thick layer of lithium metal.

[0130] Two of the constructed cells were discharged prior to safety testing and the actual capacity of these cells was found to be 1.7 Ah and the specific capacity was 1575 mAh / g SnO2.

[0131] Figure 16 is a plot of temperature and voltage for a cell constructed as above and subjected to a nail penetration test. The test was performed at room temperature and no events (such as fire) were observed. It can also be seen that the temperature and voltage remain stable.

[0132] FIG. 17A is a plot of temperature and voltage of a cell constructed as described above and subjected to an overcharge test. A current of 1 A was applied. No adverse events were observed over the test period, except for gas evolution from the cell. FIG. 17B is a plot of the overcharge test of FIG. 17A, focusing on the start of the test.

[0133] It should be understood that the examples constructed for penetration testing purposes are not intended to be limiting with respect to the entire disclosure herein. Cells and batteries of various sizes, capacities, and materials may be constructed in accordance with the present disclosure. Utilizing the AMOs of the present disclosure, such batteries will benefit from the improved safety demonstrated herein, whether such safety is ultimately due to lithium passivation, low voltage, or other factors.

[0134] Embodiments of electrochemical cells constructed incorporating AMO materials as the cathode and lithium as the electrode have been tested to successfully undergo up to 900 or more charge-discharge cycles without catastrophic, destructive failure. In other words, embodiments of electrochemical cells constructed incorporating AMO materials as the cathode and lithium as the electrode have been tested to successfully undergo up to 900 or more charge-discharge cycles and still retain a charge and maintain useful capacity.

[0135] Without wishing to be bound by any theory, the improved safety provided by the use of AMO-based cathode materials in lithium batteries may result from the ability of the AMO materials to passivate metallic lithium and prevent the formation of dendrites. The inventors observed that upon cycling, the metallic lithium anode did not appear to grow or form dendrites, but instead exhibited a softer, less crystalline structure. In some embodiments, the metallic lithium anode may be passivated, such as by cycling, as a component of an electrochemical cell described herein, and then removed from the electrochemical cell and used as an electrode in a new electrochemical cell with a different cathode. In addition, cells constructed according to the present disclosure utilize low operating voltages, such as between 1-2 volts, which contrasts with the typical voltages of lithium or lithium-ion battery cells, which typically operate at about 3-4.2 volts. Such differences in operating voltages may partially explain the safety of the disclosed cells.

[0136] With respect to cell or battery constructions using lithium as the anode according to the present disclosure, in some embodiments, the entire anode (100%) is metallic lithium. The metallic lithium need only be substantially pure in that a small percentage of the anode may contain trace elements and impurities that do not measurably affect the performance of the cell or battery. In various embodiments, the anode comprises at least 50%, 55%, 60%, 65%, 75%, 80%, 85%, 90%, or 95% metallic lithium.

[0137] For purposes of this disclosure, the term "metallic lithium" refers to lithium in its neutral atomic state (i.e., non-ionic state). The term metallic lithium is intended to distinguish it from other forms of lithium, including lithium ions and lithium compounds. The term metallic lithium may refer to neutral atomic lithium present in a mixture that includes lithium atoms, such as a mixture of lithium and other elements, compounds, or substances. The term metallic lithium may refer to neutral atomic lithium present in a lithium alloy, such as a metal mixture that includes lithium and one or more other metals. The term metallic lithium may refer to neutral atomic lithium present in a composite structure that includes lithium and one or more other materials. It will be understood that an electrode comprising or including metallic lithium may include other materials in addition to lithium, although metallic lithium may correspond to the active material of such an electrode. In some cases, the anode of an electrochemical cell includes metallic lithium.

[0138] For purposes of this disclosure, metallic lithium may be taken to mean lithium that has not reacted with other elements to form compounds (at least during construction of the battery or cell). In some embodiments, a portion of the anode may be metallic lithium and a portion of the anode may be a lithium compound containing various percentages of lithium that has reacted with other elements to form lithium compounds. The metallic lithium may be disposed on or within the anode such that it is geometrically separated relative to the lithium compound portion of the anode.

[0139] Referring now to FIG. 18, a perspective view of a cathode 1800 according to an embodiment of the present disclosure is shown. FIG. 18 is not to scale. The cathode 1800 comprises 33.3% SnO2 in the form of AMO. The AMO was prepared according to the method described above. Ketjen Black EC-300J (SA: ∼800 μm) was dissolved in NMP solvent. 2A slurry of 80 wt % Ketjen Black and 20 wt % PVDF was prepared and coated on a 10 μm thick copper foil 1802 to form a carbon layer 1804. The slurry composition was 80 wt % Ketjen Black and 20 wt % PVDF. The coated tape was dried in a vacuum oven at 100° C.

[0140] SnO2(AMO), Ketjen Black and PVDF were mixed at 33.3 wt% each and NMP solvent was added to prepare a slurry and coated onto a portion of Ketjen Black coated copper foil (1802, 1804) to form the carbon / SnO2 layer 1806. The resulting tape was dried in a vacuum oven at 100°C (overnight) and calendered at room temperature. The thickness of the tape was measured using a micrometer in the SnO2 coated area and the Ketjen Black (only) coated area. The Ketjen Black layer 1804 is about 8 μm thick and the electrode layer 1806 is about 2 μm thick. The foil layer 1802 is about 10 μm thick, giving a total thickness of the cathode 1800 of about 18 μm.

[0141] The calendar tape was punched into circular disks on the Ketjenblack (only) area and the SnO2 coated area. The weight of the Ketjenblack disk was subtracted from the SnO2 disk to determine the total mass of the electrode material. For one cell type tested, the total mass of the electrode material is 0.0005g (after subtracting the Ketjenblack disk weight) and the active material content is 0.000167g (33.3% of the total mass).

[0142] Several key elements of Cathode 1800 are (1) layering using a carbon undercoat, (2) the use of Ketjenblack high surface area carbon in both the undercoat and topcoat, (3) a 33% active material topcoat, and (4) a thin (~2um) topcoat layer. All of these parameters may be further developed.

[0143] In some embodiments, carbons other than Ketjen Black are used. Binders other than PVDF may be used. The cathode may be constructed of one or more layers. The percentage of active material may be greater than or less than 33%. The thickness of one or more layers may be greater than or less than 2um. Various current collectors may be used to optimize the cell structure.

[0144] It should be understood that the above example provides one example of a lower active material loading in an electrode than previously believed to promote optimal performance and capacity. As previously mentioned, the conventional preference for active loading is 90%, 95%, or even more if possible. In accordance with the present embodiment, the active loading may be less than 80% w / w. In some embodiments, the calculation of the active loading percentage may be the total active loading including the various conductive layers of the electrode. For example, a layer having a higher (but still low according to the teachings of the prior art) active material loading of 33% may be combined with a conductive layer containing little or no active material to provide 23% of the total active material loading of the entire electrode. In various embodiments, the total active material loading of the electrode is less than 63% at most. In another embodiment, the active material loading is between 23% and 33% in total. In yet another embodiment, the active material loading is between 11% and 14% in total.

[0145] Materials according to the present disclosure (e.g., AMO SnO2) exhibit specific energy densities comparable to those of fossil fuels, which the prior art scientific literature teaches is not possible. The same effect is observed with non-AMO metal oxides (e.g., tin oxide, titanium dioxide, and / or iron oxide) when constructed as electrodes and batteries according to the methods of the present disclosure. This suggests that the mechanism of operation of these materials as active materials is outside the scope of what is currently known or taught.

[0146] As described herein, non-AMO metal oxides can be constructed into electrodes with significantly lower active material loadings than those taught by the prior art. For example, the active loadings may be less than 50 wt%, such as 30-40 wt%, 20-25 wt%, or especially 21 wt% or 33 wt%. The formation of the electrode may be performed by repeatedly applying multiple layers of active material until a desired thickness is reached. Conductive carbon may also be laminated with the active material. The conductive carbon may be applied at the same or different loading density as the active material. For example, the active material and conductive carbon may both be present at 20-25 wt%, such as 21 wt%. In some embodiments, applying the active material in multiple thin layers has been found to improve performance over a single thicker layer.

[0147] Referring now to Figure 19, a bar graph is shown comparing the lithiation capacity of various metal oxides using standard construction techniques versus construction techniques according to the present disclosure. AMO tin oxide, AMO iron oxide, and non-AMO tin oxide were used initially with high active material loadings and other standard construction techniques. The AMO tin oxide particle size was on the order of 5 nm. The non-AMO tin oxide particle size was on the order of 20 nm.

[0148] When AMO tin oxide was utilized with standard construction techniques, the lithiation capacity was approximately 2000 mAh / g. When constructed as an electrode with low active material loading (e.g., approximately 21 wt%) and layered with nanoparticulate conductive carbon (also approximately 21 wt%), the lithiation capacity increased to over 10,000 mAh / g. When the same tests were performed, the AMO iron oxide increased the lithiation capacity from just under 2000 mAh / g to approximately 8000 mAh / g. Surprisingly, the non-AMO tin oxide also increased from less than 2000 mAh / g to over 6000 mAh / g. The average increase using the high capacity construction method was approximately 314%.

[0149] According to embodiments of the present disclosure, blends of materials can be utilized as actives in the construction of electrodes (e.g., anodes and / or cathodes), cells, and batteries. According to exemplary embodiments, AMOs of the present disclosure, such as tin oxide AMOs, can be blended with materials such as LiCOO2, FeS2, MnO2, and / or other known battery active materials to improve performance.

[0150] The AMOs can be blended with non-acidified metal oxides according to known methods to produce active materials for use in battery electrodes and other applications. The AMOs can be blended with non-acidified metal oxides by simple mechanical mixing or milling. The mechanical mixing or milling can be performed either in the dry or wet state. They can be blended with suitable surfactants to control and enhance the homogeneity and dispersibility of the mixture. The blends can be used as dry materials or as wet suspensions. The blends can be used to form electrodes by compacting, casting from a slurry, or printing.

[0151] 20 is a graph of voltage versus energy for MnO2 as the active material blended with various amounts of AMO tin according to the present disclosure. Shown is a baseline of only MnO2 as the active material, as well as blends incorporating 2, 5, and 8% tin oxide AMO according to the present disclosure. As can be seen, all blends provide an increase in energy. As little as 8% AMO provides an energy increase of over 50% according to the present disclosure.

[0152] As mentioned above, metal oxides are expected to be basic, and metal oxides used as battery active materials in particular are known to be basic. It is unexpected that blending an acidic material with a neutral or basic material would result in improved energy density. This runs counter to accepted chemistry thinking that acids and bases neutralize each other, thereby losing any inherent performance characteristics that an acid alone or a base alone may provide. It is a particularly unexpected result that the presence of acidic and basic components results in positive and synergistic effects. However, the degree of positive effect and optimal ratio of AMO and non-AMO activity are not necessarily linear or predictable. The optimal point for enhancing energy density in each blend of an individual AMO with one of the many possible types of non-AMO activity must be experimentally determined. Nevertheless, benefits can be observed across a wide range of activities. The blends and ranges tested and shown in Figure 20 are exemplary. In other embodiments, the AMO may range from <1%, 1-5%, 5-10%, 10-20%, 10-30%, 30-40%, 50-99%, or >99% of the active material. In some embodiments, the exact ratio is derived based on the desired cost vs. energy of the final product (e.g., material, electrode, cell, battery, etc.).

[0153] The exact ratio (AMO / non-AMO) can also be derived based on the type, size, and physical / mechanical properties of the electrode that needs to be formed. The exact ratio can also be derived based on the desired electrical performance. A lower ratio of AMO to non-AMO will give a voltage profile that is more similar to that of non-AMO alone. A higher ratio will give a voltage profile that is more similar to that of AMO alone. This gives AMO / non-AMO blends unique tunability to target specific electronic use cases that do not currently exist in the battery industry. Thus, the exact ratio of AMO to non-AMO for any given application will represent a unique blend of desired electrical performance, energy density, and cost.

[0154] Applicants have tested several different AMO and non-AMO blends and found that adding various AMOs according to the present disclosure with non-AMOs such as lithium manganese oxide, lithium manganese nickel oxide, and manganese nickel oxide has a positive effect. Blending methods have also been shown to work with lithium titanium oxide and titanium oxide, lithium iron phosphate and iron phosphate, lithium nickel cobalt aluminum oxide and nickel cobalt aluminum oxide, and lithium nickel manganese cobalt oxide and nickel manganese cobalt oxide. It should also be understood that the AMO / non-AMO blends of the present disclosure have been determined to be useful in both primary and secondary applications, with improved performance observed in each.

[0155] In some embodiments, the electrode or active material blend is composed exclusively of the identified AMOs and non-AMOs. In some embodiments, the active material of the electrode is composed exclusively of the identified AMOs and non-AMOs, but the electrode may include additional carbon, conductors, and non-active components. In other embodiments, the electrode or active material blend may include the identified AMOs and non-AMOs, as well as other materials known in the art.

[0156] In yet another embodiment, the AMO of the present disclosure may be incorporated into or blended with the active materials used in so-called alkaline batteries. Such battery chemistries find wide application in standard battery sizes such as "AA", "AAA", "C", "D" and other standard size batteries familiar to consumers. Typically, such batteries, when used with standard alkaline chemistries, are primary discharge batteries. However, the present disclosure and AMO alkaline blend active materials may find application in primary and secondary discharge systems.

[0157] 21, a side cross-sectional view of an exemplary battery 2200 based on alkaline chemistry is shown. The battery 2200 can include a positive terminal 2202 physically separated from a negative terminal 2204. The anode 2206 can be electrically connected to the negative terminal 2204 via a current collector 2208. The cathode 2210 is separated from the anode 2206 by a separator 2212 and electrically connected to the positive terminal 2202. Some embodiments include a protective end cap 2214 that holds the internal components in place within the outer casing 2216 without inducing a short circuit (e.g., the end cap 2214 can be non-conductive and resistant to degradation from any of the internal battery chemistries). Other physical features such as vents, as well as other safety and structural components known in the art, may be included but are not shown for simplicity.

[0158] Referring now to FIG. 22, an alkaline cell containing 10 wt. % of the disclosed acidified SnO2 blended with manganese dioxide (the remainder of the cell is a Zn anode and an alkaline (basic) electrolyte) shows improved discharge capacity compared to a conventional alkaline electrode. In prior art alkaline chemistries, the anode may include a zinc-based material, such as zinc powder, and a basic electrolyte, such as potassium hydroxide electrolyte. Prior art cathodes may include manganese dioxide (MnO2), optionally blended with carbon powder. In other chemistries, lithium may be incorporated to provide a lithium manganese oxide (LMO) cell or battery and a carbonate electrolyte. According to embodiments of the present disclosure, the anode 2206 may include zinc and may also contain an electrolyte, such as potassium hydroxide. The cathode 2210 may include manganese dioxide or LMO blended or combined with AMO, as disclosed herein.

[0159] The percentage of AMO that can be blended with MnO2 or LMO or other alkaline chemical materials may range from 1-99%, with exemplary embodiments ranging from 1%, 2%, 5%, 8%, 10%, and 12%. Considering the amount of AMO incorporated, the most effective in terms of improving the performance of the final battery or cell may be in the range of 8-14%.

[0160] Although the above examples relate to batteries or cells that may find use in place of AA, AAA, C, and / or D cells, the use of the AMOs of the present disclosure in blends with traditional alkaline chemistries is not limited to those specific examples or applications. For example, blends of AMOs of the present disclosure may be utilized in button cells, standard 9V batteries, and other form factors. Additionally, AMOs may be combined with manganese or LMO cathode materials in slurry cast, tape cast, pressed pellets, pressed rings, or other construction processes. All references throughout this application, such as patent documents, including issued or granted patents or equivalents, patent application publications, and non-patent literature documents, or other materials, are incorporated herein by reference in their entirety, as if individually incorporated by reference.

[0161] All patents and publications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains. References cited in this specification are incorporated herein by reference in their entirety to indicate the state of the art at the time of filing, if necessary, and it is intended that this information can be used herein to exclude (e.g., disclaim) certain embodiments that are in the prior art. For example, when a compound is claimed, it should be understood that compounds known in the prior art, including specific compounds disclosed in the references disclosed herein (particularly the patent documents referenced), are not intended to be included in the claim.

[0162] When a group of substituents is disclosed herein, it is understood that all individual members of the group, and all subgroups and classes that can be formed using the substituents are disclosed separately.When a Markush group or other grouping is used herein, all individual members of the group, and all possible combinations and subcombinations of the group are individually included in the disclosure.As used herein, "and / or" means that one, all, or any combination of the items in the list separated by "and / or" is included in the list; for example, "1, 2, and / or 3" is equivalent to "1" or "2" or "3", or "1 and 2" or "1 and 3" or "2 and 3", or "1, 2, and 3".

[0163] Unless otherwise stated, the present invention can be practiced using any combination or formulation of components described or exemplified. The specific names of materials are intended to be exemplary, and it is recognized that one skilled in the art can give different names to the same materials. One skilled in the art will understand that methods, device elements, starting materials, and synthetic methods other than those specifically exemplified can be used in the practice of the present invention without resorting to undue experimentation. All art-known functional equivalents of such methods, device elements, starting materials, and synthetic methods are intended to be included in the present invention. When ranges are given herein, for example, temperature ranges, time ranges, or composition ranges, all intermediate ranges and subranges, and all individual values ​​included in the given ranges are intended to be included in the present disclosure.

[0164] As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended, and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of" excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. Recitations herein of the term "comprising," particularly in describing components of a composition or in describing elements of a device, are understood to encompass compositions and methods that consist essentially of and consist of the recited components or elements. The invention illustratively described herein may be suitably practiced in the absence of any element or limitation not specifically disclosed herein.

[0165] The terms and expressions used are used as terms of description and not of limitation, and no intention is intended in the use of such terms and expressions to exclude the features shown and described or equivalents of portions thereof, recognizing that various modifications are possible within the scope of the invention as described in the claims. Thus, although the invention has been specifically disclosed by preferred embodiments and optional features, it should be understood that modifications and variations of the concepts disclosed herein may be possible by those skilled in the art, and such modifications and variations are considered to be within the scope of the invention as defined by the claims.

Claims

1. an anode (106) comprising zinc; a cathode (104) comprising a non-acidic metal oxide and an acidic metal oxide, the acidic metal oxide has a particle size of less than 100 nm, the acidic metal oxide has a pH<5 and a Hammett function H>-12, the pH being measured when the acidic metal oxide is suspended in water at 5 wt %; the acidic metal oxide represents 1% to 15% by weight of the cathode (104); the non-acidic metal oxide represents 85% to 99% by weight of the cathode (104); and an electrolyte (108) disposed between the anode (106) and the cathode (104), wherein the electrolyte is a basic alkaline electrolyte; Including, The non-acidic metal oxide is manganese dioxide or manganese nickel oxide. Battery cell (100).

2. 10. The battery cell (100) of claim 1, wherein the acidic metal oxide is of the form SnOx / G, where Sn is tin, Ox is total oxygen, x is equal to 1 or 2, G is at least one electron-withdrawing surface group, and / or distinguishes between the metal oxide and the at least one electron-withdrawing surface group.

3. The battery cell (100) of claim 1, wherein the electrolyte (108) comprises KOH.

4. A method for increasing the discharge capacity of a battery cell (100), the battery cell (100) including an anode (106) comprising zinc, a cathode (104), and an electrolyte (108) disposed between the anode (106) and the cathode (104), the method comprising: blending a non-acidic metal oxide with an acidic metal oxide to form an active material of the cathode; constructing the battery cell (100) using the active material in the cathode (104); Including, the electrolyte is a basic alkaline electrolyte; the non-acidic metal oxide is manganese dioxide or manganese nickel oxide; the acidic metal oxide has a particle size of less than 100 nm, the acidic metal oxide has a pH<5 and a Hammett function H>-12, the pH being measured when the acidic metal oxide is suspended in water at 5 wt %; the acidic metal oxide represents 1% to 15% by weight of the cathode (104); The method, wherein the non-acidic metal oxide represents 85% to 99% by weight of the cathode (104).

5. The method of claim 4, wherein the acidic metal oxide represents 1% to 8% by weight of the cathode (104).

6. 5. The method of claim 4, wherein the acidic metal oxide is of the form MnOx / G, where Mn is manganese, Ox is total oxygen, x is equal to 2, G is at least one electron-withdrawing surface group, and / or distinguishes between the MnOx and the at least one electron-withdrawing surface group.

7. The method of claim 4, wherein the electrolyte (108) comprises KOH.

8. The method of claim 4 , wherein the acidic metal oxide comprises tin oxide, manganese oxide, iron oxide, titanium dioxide, zirconium dioxide, or a combination thereof.

9. 10. The battery cell (100) of claim 1, wherein the acidic metal oxide comprises tin oxide, manganese oxide, iron oxide, titanium dioxide, or zirconium dioxide.

10. 10. The battery cell (100) of claim 1, wherein the acidic metal oxide comprises a mixed metal oxide including at least one of tin oxide, manganese oxide, iron oxide, titanium dioxide, and zirconium dioxide.

11. 10. The battery cell (100) of claim 1, wherein the acidic metal oxide comprises an acidic manganese oxide and the non-acidic metal oxide comprises a manganese oxide.

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