A battery comprising an electrochemically active cathode material of beta-delithiated layered nickel oxide

Abstract

To provide an electrochemically active cathode material for a battery.SOLUTION: An electrochemically active cathode material includes a non-stoichiometric beta-delithiated layered nickel oxide. The non-stoichiometric beta-delithiated layered nickel oxide has a chemical formula. The chemical formula is LixAyNi1+a-zMzO2*nH2O. In the formula, x is approximately 0.02 to 0.20, y is approximately 0.03 to 0.20, a is approximately 0.02 to 0.2, z is approximately 0 to 0.2, and n is approximately 0 to 1. In the chemical formula, A is an alkali metal. The alkali metal includes potassium, rubidium, cesium, and any combination thereof. In the chemical formula, M comprises an alkaline earth metal, a transition metal, a non-transition metal, and any combination thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 503,829, filed May 9, 2017, under 35 U.S.C. § 119(e), the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to electrochemically active cathode materials, and more particularly, to electrochemically active cathode materials of non - stoichiometric beta - delithiated layered nickel oxides and batteries containing the same.

Background Art

[0003] Electrochemical cells, i.e., batteries, are commonly used as sources of electrical energy. A battery typically includes a negative electrode, usually called an anode, and a positive electrode, usually called a cathode. The anode includes an electrochemically active anode material that can be oxidized. The cathode includes an electrochemically active cathode material that can be reduced. The electrochemically active anode material can reduce the electrochemically active cathode material. A separator is disposed between the anode and the cathode. An ion - conductive electrolyte solution is in intimate contact with the cathode, anode, and separator. The components of the battery are typically disposed within a can, i.e., a housing, made of metal.

[0004] When a battery is used as an electrical energy source in an electronic device, it is electrically connected to the anode and the cathode to conduct electrons to the device, generating oxidation and reduction reactions at each electrode to provide power to the electronic device. The electrolyte is in contact with the anode, cathode, and separator. The electrolyte contains ions that flow through the separator between the anode and the cathode to maintain the charge balance of the entire battery during discharge.

[0005] There is an increasing need to manufacture batteries suitable for powering up-to-date electronic devices such as toys, remote controls, audio devices, flashlights, digital cameras and their peripherals for photography, electronic games, toothbrushes, radios, watches, etc. To meet this need, the battery may include a high loading of electrochemically active anode and / or cathode materials so as to increase the capacity and service life. However, the batteries are also provided in common sizes, such as AA, AAA, AAAA, C and D battery sizes, having defined outer dimensions and a restricted internal volume. Thus, the ability to increase only the loading of the electrochemically active material to achieve a better performing battery is limited.

[0006] The electrochemically active cathode material of a battery is another design feature that can be adjusted to enhance performance. For example, an electrochemically active material having a larger volume capacity and weight capacity can result in a better performing battery. Similarly, an electrochemically active material having a higher oxidation state can also result in a better performing battery. However, the electrochemically active material selected must provide a range of closed circuit voltages, i.e., operating voltages, acceptable to the devices that the battery can power. If the open circuit voltage (OCV) or operating voltage of the battery is too high, the device may be damaged. Conversely, if the operating voltage of the battery is too low, the device may not function at all.

[0007] In addition, electrochemically active cathode materials such as transition metal oxides in a high oxidation state can be highly reactive. Such high reactivity of electrochemically active cathode materials can cause gas generation when the electrochemically active cathode material is incorporated into the battery and comes into contact with the electrolyte solution. The generated gas can lead to problems with the structural integrity such as conduction within the cathode, and / or an increase in pressure within the battery that results in leakage of the electrolyte from the battery. Transition metal oxides in a high oxidation state can also cause harmful reactions with other battery components, conductive carbon additives such as graphite, other additives such as (one or more) surfactants, and / or separators. Transition metal oxides in a high oxidation state may also tend to react with the electrolyte, which can lead to other structural problems within the battery such as cathode swelling, and / or consumption of water that results in an unfavorable water balance within the battery. Also, a battery containing a transition metal oxide in a high oxidation state as an electrochemically active cathode material may exhibit thermodynamic instability and a high self-discharge rate when the battery is stored over a long period of time. In addition, it is necessary to appropriately balance the ratios of both the water content and the potassium hydroxide content to the content of the electrochemically active material of the battery in order to maximize the utilization of both electrochemically active electrode materials. Furthermore, by selecting appropriate ratios of both the water content and the potassium hydroxide content to the content of the electrochemically active material, battery performance can be improved over a plurality of discharge rate regimes. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] There is a need to provide an electrochemically active cathode material for a battery that addresses the above-described needs. The electrochemically active cathode material of the non-stoichiometric beta delithiated layered nickel oxide of the present invention particularly addresses these needs. MEANS FOR SOLVING THE PROBLEMS

[0009] In one embodiment, the present invention is directed to a battery. The battery includes a cathode, an anode, a separator between the cathode and the anode, and an electrolyte. The cathode includes a conductive additive and an electrochemically active cathode material. The electrochemically active cathode material includes a non-stoichiometric beta delithiated layered nickel oxide. The non-stoichiometric beta delithiated layered nickel oxide has a chemical formula. The chemical formula is Li x A y Ni 1+a-z M z O2·nH2O, where x ranges from about 0.02 to about 0.20, y ranges from about 0.03 to about 0.20, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, and n ranges from about 0 to about 1. In the chemical formula, A is an alkali metal. The alkali metal includes potassium, rubidium, cesium, and any combination thereof. In the chemical formula, M includes alkaline earth metals, transition metals, non-transition metals, and any combination thereof. The alkaline earth metals can include magnesium, calcium, and combinations thereof. The transition metals can include cobalt, manganese, titanium, yttrium, and combinations thereof. The non-transition metals can include aluminum, gallium, indium, germanium, tin, and any combination thereof. The anode includes an electrochemically active anode material. The electrochemically active anode material includes zinc, zinc alloys, and any combination thereof.

[0010] In another embodiment, the present invention is directed to an electrochemically active cathode material including a non-stoichiometric beta delithiated layered nickel oxide having a layered crystal structure, the layered crystal structure being characterized by a lattice including a plurality of NiO2 layers, the NiO2 lattice including an ordered O1-type layer stacking configuration, at least one O3-type layer stacking defect, and at least one gamma nickel oxyhydroxide (γ-NiOOH)-like layer stacking defect.

[0011] This specification identifies and particularly claims the subject matter regarded as forming the present invention, which is considered to be better understood when the following description is read in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 6A

Figure 6B

Figure 7

[0013] An electrochemical cell, i.e., a battery, can be primary or secondary. A primary battery, for example, means that it is discharged only once and discarded until it is consumed. Primary batteries are described, for example, in David Linden, Handbook of Batteries (4th ed. 2011). A secondary battery is intended to be charged. A secondary battery can be discharged and recharged many times, for example, 50 times, 100 times, or more. Secondary batteries are described, for example, in David Linden, Handbook of Batteries (4th ed. 2011). Thus, a battery can include various combinations of electrochemical couples and electrolytes. Although the descriptions and examples provided herein generally target primary alkaline electrochemical cells, i.e., batteries, it should be understood that the present invention applies to both primary and secondary batteries having aqueous, non-aqueous, ionic liquid, and solid electrolyte systems. Therefore, primary and secondary batteries including the aforementioned electrolytes are within the scope of this application, and the present invention is not limited to any specific embodiment.

[0014] Referring to FIG. 1, a primary alkaline electrochemical cell, i.e., a battery 10, including a cathode 12, an anode 14, a separator 16, and a housing 18 is shown. The battery 10 also includes a current collector 20, a seal 22, and an end cap 24. The end cap 24 functions as the negative terminal of the battery 10. A positive protrusion 26 is at the opposite end of the battery 10 as viewed from the end cap 24. The positive protrusion 26 can function as the positive terminal of the battery 10. An electrolyte is dispersed throughout the battery 10. The cathode 12, anode 14, separator 16, electrolyte, current collector 20, and seal 22 are housed within the housing 18. The battery 10 can be, for example, a AA, AAA, C, D, or single cell alkaline battery.

[0015] The housing 18 can be of any conventional type generally used in primary alkaline batteries and can be made of any suitable substrate, such as cold rolled steel or nickel plated cold rolled steel. The housing 18 may have a cylindrical shape. The housing 18 may be of any other suitable non-cylindrical shape. The housing 18 may have a shape including at least two parallel plates, such as rectangular, square, or prismatic. The housing 18 may be deep drawn from a sheet of a substrate such as cold rolled steel or nickel plated steel. The housing 18 may be drawn into a cylindrical shape, for example. The housing 18 may have at least one open end. The housing 18 may have a closed end and an open end with a side wall therebetween. The inner surface of the side wall of the housing 18 can be treated with a material that provides a low electrical contact resistance between the inner surface of the side wall of the housing 18 and an electrode such as the cathode 12. The inner surface of the side wall of the housing 18 may be plated, for example, with nickel, cobalt, and / or painted with a carbon-containing paint to reduce the contact resistance between the inner surface of the side wall of the housing 18 and the cathode 12, for example.

[0016] The cathode 12 includes at least one electrochemically active cathode material. The electrochemically active cathode material can be a non-stoichiometric beta delithiated layered nickel oxide. The beta delithiated layered nickel oxide has the general chemical formula Li x A y Ni 1+a-z M z O2·nH2O, where x ranges from about 0.02 to about 0.20, y ranges from about 0.03 to about 0.20, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, n ranges from about 0 to about 1, A includes an alkali metal, and M includes an alkaline earth metal, a transition metal, a non-transition metal, and any combination thereof. Since a is positive so that a non-stoichiometric amount of nickel (and / or other metal M) (i.e., excess nickel relative to the amount of nickel (and / or other metal)) necessary to balance the charge of the oxygen atoms is always present in the material, the beta delithiated layered nickel oxide is considered non-stoichiometric. The non-stoichiometric beta delithiated layered nickel oxide has the general chemical formula Li x A y Ni 1+a-z M z O2·nH2O, where x ranges from about 0.03 to about 0.12, y ranges from about 0.03 to about 0.20, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, n ranges from about 0 to about 1, A includes an alkali metal, and M includes an alkaline earth metal, a transition metal, a non-transition metal, and any combination thereof.

[0017] In an embodiment of the non-stoichiometric beta delithiated layered nickel oxide, x can be in the range of 0.02 to 0.2, for example, 0.02 to 0.18, 0.02 to 0.16, 0.02 to 0.15, 0.03 to 0.20, 0.03 to 0.19, 0.03 to 0.15, 0.03 to 0.12, 0.05 to 0.19, or 0.05 to 0.15. In an embodiment, y can be within 0.03 to 0.20, for example, 0.03 to 0.17, 0.03 to 0.15, 0.03 to 0.13, 0.06 to 0.20, 0.06 to 0.17, 0.06 to 0.15, 0.06 to 0.13, 0.08 to 0.17, 0.08 to 0.15, or 0.08 to 0.13. In an embodiment, a is in the range of 0.02 to 0.20, for example, 0.02 to 0.18, 0.02 to 0.16, 0.03 to 0.20, 0.03 to 0.17, 0.03 to 0.15, 0.04 to 0.20, 0.04 to 0.17, 0.04 to 0.15, 0.04 to 0.13, or 0.04 to 0.11. When a is less than 0.02, it can be seen that the stability of the non-stoichiometric beta delithiated layered nickel oxide is low. In an embodiment, z can be in the range of 0 to 0.20, for example, 0.03 to 0.20, or 0.04 to 0.20. In an embodiment, z can be 0. In an embodiment where z is 0, a can be in the range of 0.02 to 0.20, for example, 0.02 to 0.16, 0.03 to 0.15, or 0.02 to 0.15. In an embodiment, the difference (a - z) can be in the range of 0.02 to 0.20, for example, 0.02 to 0.16, 0.04 to 0.20, 0.04 to 0.16, 0.06 to 0.16, or 0.08 to 0.18. In an embodiment, A can be potassium, and y can be in the range of 0.06 to 0.14, for example 0.08 to 0.13. In an embodiment, z is 0, and since 1+(a - z) is greater than 1, Ni itself exists in a non-stoichiometric amount, for example, 1+(a - z) can be in the range of about 1.02 to about 1.20.

[0018] Electrochemically active cathode materials can have a weight capacity. The electrochemically active cathode material of non-stoichiometric beta delithiated layered nickel oxide can have a weight capacity greater than about 340 mAh / g or greater than about 350 mAh / g. The electrochemically active cathode material of non-stoichiometric beta delithiated layered nickel oxide can have a weight capacity from about 340 mAh / g to about 400 mAh / g, from about 350 mAh / g to about 400 mAh / g, from about 340 mAh / g to about 380 mAh / g, or from about 360 mAh / g to 400 mAh / g.

[0019] The elements of Group 1A of the periodic table are generally called alkali metals. Alkali metals can include elements from Group 1A of the periodic table or any combination of elements. Alkali metals can include, for example, potassium (K), rubidium (Rb), cesium (Cs), and any combination thereof.

[0020] The elements of Group IIA of the periodic table are usually called alkaline earth metals. Alkaline earth metals can include elements from Group IIA of the periodic table or any combination of elements. Alkaline earth metals can include, for example, magnesium (Mg), calcium (Ca), and combinations thereof.

[0021] The elements of Groups IB - VIIIB of the periodic table are usually called transition metals. Transition metals can include elements from Groups IB - VIIIB of the periodic table or any combination of elements. Transition metals can include, for example, cobalt (Co), manganese (Mn), yttrium (Y), titanium (Ti), zinc (Zn), and any combination thereof.

[0022] Non-transition metals can include, for example, aluminum (Al), gallium (Ga), germanium (Ge), indium (In), tin (Sn), and any combination thereof.

[0023] The alkali metal can be, for example, potassium (K). The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide is, for example, Li x K y Ni 1+a-z M z O2·nH2O, where x ranges from about 0.02 to about 0.20, y ranges from about 0.03 to about 0.20, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, and n ranges from about 0 to about 1. The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide is, for example, Li x K y Ni 1+a-z M z O2·nH2O, where x ranges from about 0.02 to about 0.20, y ranges from about 0.08 to about 0.13, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, and n ranges from about 0 to about 1, and M includes alkaline earth metals, transition metals, non-transition metals, and any combination thereof. The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide is, for example, Li 0.13 K 0.13 Ni 1.16 O2·0.26H2O or Li 0.07 K 0.13 Ni 1.11 O2·0.53H2O may also be possible.

[0024] The alkaline earth metal can be, for example, magnesium (Mg). The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide is, for example, Li x K y Ni 1+a-z Mg z O2·nH2O, where x ranges from about 0.02 to about 0.2, y ranges from about 0.03 to about 0.2, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, and n ranges from about 0 to about 1. The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide is, for example, Li 0.15 K 0.10 Ni 1.05 Mg 0.04 O2·0.24H2O may also be possible.

[0025] The transition metal can be, for example, cobalt (Co). The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide can be, for example, Li x K y Ni 1+a-z Co z O2·nH2O, where x ranges from about 0.02 to about 0.2, y ranges from about 0.03 to about 0.2, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, and n ranges from about 0 to about 1. The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide can be, for example, Li 0.04 K 0.011 Ni 1.03 Co 0.03 O2·nH2O may also be.

[0026] The non-transition metal can be, for example, aluminum (Al). The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide can be, for example, Li x K y Ni 1+a-z Al z O2·nH2O, where x ranges from about 0.02 to about 0.2, y ranges from about 0.03 to about 0.2, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, and n ranges from about 0 to about 1. The chemical formula of the non-stoichiometric beta delithiated layered nickel oxide can be, for example, Li 0.12 K 0.09 Ni 1.08 Al 0.02 O2·0.18H2O may also be.

[0027] The content of (one or more) alkali metals, (one or more) alkaline earth metals, (one or more) transition metals, and / or (one or more) non-transition metals in the non-stoichiometric β-delithiated layered nickel oxide can be determined by any acceptable method known in the art. For example, the content of (one or more) alkali metals and (one or more) transition metals in the non-stoichiometric β-delithiated layered nickel oxide can be determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and / or atomic absorption (AA) spectroscopy. For ICP-AES analysis and / or AA analysis, standard methods described, for example, in J.R. Dean, Practical Inductively Coupled Plasma Spectroscopy, pp. 65-87 (2005) and B. Welz and M.B. Sperling, Atomic Absorption Spectrometry, pp. 221-294 (3rd ed. 1999) can be used to complete the analysis. To complete the ICP-AES analysis of a sample material such as non-stoichiometric β-delithiated layered nickel oxide, an Ultima 2 ICP spectrometer available from HORIBA Scientific (Kyoto, Japan) can be used. The ICP-AES analysis of non-stoichiometric β-delithiated layered nickel oxide can be performed at various wavelengths depending on the elements contained in the non-stoichiometric β-delithiated layered nickel oxide. The potassium content in the non-stoichiometric β-delithiated layered nickel oxide determined by ICP-AES can be less than about 7 weight percent. The potassium content in the non-stoichiometric β-delithiated layered nickel oxide determined by ICP-AES can be from about 2 weight percent to about 7 weight percent, or from about 3 weight percent to about 7 weight percent.

[0028] The water content in the non-stoichiometric beta delithiated layered nickel oxide can be determined by any acceptable method known in the art. For example, the water content in the non-stoichiometric beta delithiated layered nickel oxide can be determined by thermogravimetric analysis (TGA). TGA determines, for example, the absorbed and adsorbed water of the sample material, the water content in the crystal lattice of the sample material, and the total water content in the sample material, by measuring the change in the weight of the sample as a function of the temperature increase. TGA is described, for example, in R.F. Speyer, Thermal Analysis of Materials (1994). To complete TGA on a sample material such as non-stoichiometric beta delithiated layered nickel oxide, a Q5000 analyzer available from TA Instruments (New Castle, Delaware, USA) can be used.

[0029] Powder X-ray diffraction (pXRD) is an analytical technique used to characterize the crystal lattice structure of sample materials such as crystalline powders. XRD analysis of a crystalline sample material will result in a characteristic diffraction pattern consisting of peaks of various intensities, widths, and diffraction angles (peak positions) corresponding to the diffraction planes of the crystal structure of the sample material. The XRD pattern can be measured with an X-ray diffractometer using, for example, Cu-Kα radiation by standard methods as described in B.D. Cullity and S.R. Stock, Elements of X-ray Diffraction (3rd ed. 2001). To complete powder XRD analysis on sample materials such as non-stoichiometric β-delithiated layered nickel oxide, a Bruker Corporation (Madison, Wisconsin, USA) D-8 Advance X-ray diffractometer can be used. Unit cell parameters such as the length and angles of the unit cell of the sample material can be determined, for example, by Rietveld refinement of the XRD pattern. For Rietveld refinement, see, for example, H.M. Rietveld, “A Profile Refinement Method for Nuclear and Magnetic Structures”, Journal of Applied Crystallography, pp. 65~71 (1969).

[0030] The crystallite size of the sample material can be determined by the peak broadening of the XRD pattern of the sample material including the silicon (Si) standard. The peak broadening analysis may be completed, for example, by the single-peak Scherrer method or the Warren-Averbach method, which are discussed, for example, in H.P. Klug and L.E. Alexander, “X-ray Diffraction Procedures for Polycrystalline and Amorphous Materials”, Wiley, pp. 618 - 694 (1974). The Warren-Averbach method can also be used to determine the residual strain and stress of the sample material.

[0031] The full width at half maximum (FWHM) can be used to characterize the relative sharpness, i.e., the broadness, of the lines within the diffraction pattern of the sample material. The FWHM can be determined by measuring the intensity of the peak, dividing the measured intensity by 2 to calculate the half intensity (half height), and measuring the width of the peak at the calculated half height.

[0032] The normalized intensity can be used together with the peak position to compare the relative efficiency of diffraction associated with specific diffraction planes within the crystal lattice of the sample material. The normalized intensity can be calculated for peaks within the same XRD pattern. All peaks of the XRD pattern can be normalized to the peak with the highest intensity (reference peak). The normalization is performed by dividing the peak represented by the number to be normalized by the intensity of the reference peak represented by a number, and multiplying by 100. For example, the reference peak may have an intensity of 425 and the peak to be normalized may have an intensity of 106. The normalized intensity of the peak is 25%, e.g., [(106 / 425)*100]. The reference peak has a normalized intensity of 100%.

[0033] The obtained XRD pattern can be compared with a known XRD pattern. The comparative XRD pattern can be generated from a known sample material. In addition, the obtained XRD pattern can be compared with known XRD patterns in, for example, the Powder Diffraction File (PDF) database available from the International Centre for Diffraction Data (Newtown Square, Pennsylvania, USA), or the Inorganic Crystal Structure Database (ICSD) available from FIZ Karlsruhe (Eggenstein-Leopoldshafen, Germany). It is determined whether the XRD pattern of the sample material obtained by comparison with the known sample material or PDF (International Center for Diffraction Data, Newtown Square, Pennsylvania) is different from, similar to, or equal to the known XRD pattern of the material. For example, the known XRD patterns in the PDF database for comparison with β-delithiated layered nickel oxide include PDF #00-06-0141 for nickel oxyhydroxide β, PDF #00-00675 for nickel oxyhydroxide γ, PDF #00-006-0075 for nickel oxide, and PDF #00-059-0463 for nickel hydroxide β.

[0034] Non-stoichiometric beta delithiated layered nickel oxide can have a characteristic powder X-ray diffraction pattern. An example of the XRD pattern of non-stoichiometric beta delithiated layered nickel oxide is shown in FIG. 4 (upper). The measured XRD pattern does not correspond to any X-ray diffraction pattern reported in, for example, the PDF database. The XRD pattern can include several peaks, or combinations of peaks, indicative of beta delithiated layered nickel oxide. The XRD pattern can include characteristic FWHM values of several peaks of beta delithiated layered nickel oxide. The XRD pattern can also include characteristic normalized intensities of several peaks of non-stoichiometric beta delithiated layered nickel oxide. The XRD pattern of non-stoichiometric beta delithiated layered nickel oxide can include a first peak. The first peak can have a peak position on the XRD pattern from about 14.9° 2θ to about 16.9° 2θ. The first peak can be, for example, about 15.4° 2θ. The XRD pattern of non-stoichiometric beta delithiated layered nickel oxide can include a second peak. The second peak can have a peak position on the XRD pattern from about 21.3° 2θ to about 22.7° 2θ. The second peak can be, for example, about 22.1° 2θ. The XRD pattern of non-stoichiometric beta delithiated layered nickel oxide can include a third peak. The third peak can have a peak position on the XRD pattern from about 37.1° 2θ to about 37.4° 2θ. The third peak can be, for example, about 37.3° 2θ. The XRD pattern of non-stoichiometric beta delithiated layered nickel oxide can include a fourth peak. The fourth peak can have a peak position on the XRD pattern from about 43.2° 2θ to about 44.0° 2θ. The fourth peak can be, for example, about 43.6° 2θ. The XRD pattern of non-stoichiometric beta delithiated layered nickel oxide can include a fifth peak. The fifth peak can have a peak position on the XRD pattern from about 59.6° 2θ to about 60.6° 2θ. The fifth peak can be, for example, about 60.1° 2θ. The XRD pattern of non-stoichiometric beta delithiated layered nickel oxide can include a sixth peak.The sixth peak may have a peak position on the XRD pattern from about 65.4° 2θ to about 65.9° 2θ. The sixth peak may be, for example, about 65.7° 2θ. The XRD pattern of the non-stoichiometric β-delithiated layered nickel oxide may include a seventh peak. The seventh peak may have a peak position on the XRD pattern from about 10.8° 2θ to about 12.0° 2θ. The seventh peak may be, for example, about 11.2° 2θ. The XRD pattern of the non-stoichiometric β-delithiated layered nickel oxide may include an eighth peak. The eighth peak may have a peak position on the XRD pattern from about 48.1° 2θ to about 48.6° 2θ. The eighth peak may be, for example, about 48.3° 2θ.

[0035] The first peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a full width at half maximum (FWHM). The FWHM of the first peak can be from about 1.01° 2θ to about 2.09° 2θ. The FWHM of the first peak can be, for example, about 1.37° 2θ. The second peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a FWHM. The FWHM of the second peak can be from about 0.86° 2θ to about 1.95° 2θ. The FWHM of the second peak can be, for example, about 1.37° 2θ. The third peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a FWHM. The FWHM of the third peak can be from about 0.23° 2θ to about 0.41° 2θ. The FWHM of the third peak can be, for example, about 0.28° 2θ. The fourth peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a FWHM. The FWHM of the fourth peak can be from about 0.40° 2θ to about 0.75° 2θ. The FWHM of the fourth peak can be, for example, about 0.60° 2θ. The fifth peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a FWHM. The FWHM of the fifth peak can be from about 0.57° 2θ to about 1.45° 2θ. The FWHM of the fifth peak can be, for example, about 0.92° 2θ. The sixth peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a FWHM. The FWHM of the sixth peak can be from about 0.27° 2θ to about 0.53° 2θ. The FWHM of the sixth peak can be, for example, about 0.36° 2θ. The seventh peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a FWHM. The FWHM of the seventh peak can be from about 0.56° 2θ to about 1.73° 2θ. The FWHM of the seventh peak can be, for example, about 1.13° 2θ. The eighth peak of the XRD pattern of non-stoichiometric β-delithiated layered nickel oxide can have a FWHM. The FWHM of the eighth peak can be from about 0.33° 2θ to about 0.58° 2θ. The FWHM of the eighth peak can be, for example, about 0.45° 2θ.

[0036] Some of the peaks in the X-ray diffraction pattern of non-stoichiometric beta delithiated layered nickel oxide have significantly larger FWHM values compared to other peaks in the diffraction pattern, e.g., the 1st, 2nd, 5th, and 7th peaks. Without intending to be bound by theory, the broadening of certain diffraction peaks in the X-ray diffraction pattern is thought to be the result of the formation of various deformation defects, such as planar defects like stacking defects, in the layered lattice structure that disrupts the long-range layer stacking configuration of the NiO2 layer of the lithium nickel oxide precursor.

[0037] In the case of nominal stoichiometric lithium nickel(III) oxide LiNiO2 (i.e., lithium nickelate), the lattice symmetry is rhombohedral and the crystal structure belongs to the R-3m space group. Nominal stoichiometric lithium nickel(III) oxide (lithium nickelate) with the general formula LiNiO2 can be prepared by the procedure described by Arai et al. (Solid State Ionics 80 (1995) 261 - 269). Alternatively, stoichiometric lithium nickelate can also be purchased from commercial sources (e.g., American Elements, Los Angeles, California). The powder X-ray diffraction pattern of nominal stoichiometric lithium nickelate is shown in Figure 2, whether it is manufactured by Arai or commercially obtained. The lattice structure of lithium nickelate is composed of a stacking of NiO2 layers with trigonal symmetry and cubic close packing in the oxygen sublattice. The basic building block of the NiO2 layer is a NiO6 octahedron that shares edges with other NiO6 octahedra located in the same layer to form an extended edge-sharing network. Lithium ions are located at octahedral sites defined by oxygen atoms in the interlayer region between NiO2 layers. The NiO2 layers are systematically aligned with respect to each other to form a stacking in which NiO2 layers with long-range order and lithium-containing layers overlap alternately. This type of long-range order can be classified as an O3-type layer stacking configuration, as shown in Figure 5A, with a repeating unit containing three NiO2 layers with AB CA BC oxygen filling.

[0038] When the nickel(III) in stoichiometric lithium nickelate is oxidized to nickel(IV), lithium ions desorb to maintain the electrical neutrality of the overall charge without removing oxygen from the crystal lattice. Stoichiometric lithium nickelate can be delithiated by the general procedure described by Arai et al. (Electrochimica Acta 50 (2005) 1821 - 1828). The obtained Ni(IV)-containing delithiated layered nickel oxide is referred to herein as alpha-delithiated layered nickel oxide, in which almost all of the lithium ions are removed from the interlayer region, and usually only about 5 to 10% of the lithium (based on the total lithium in the lithium nickelate precursor) remains. When lithium ions are removed from the intermediate layer of lithium nickelate, the NiO2 layers can slide more easily relative to each other and form different stacking configurations with lower energy to minimize the electrostatic repulsive force between nickel ions and oxygen ions within the opposing NiO2 layers. The displacement of two adjacent NiO2 layers can occur as soon as some of the lithium ions desorb from the interlayer space between them, resulting in local regions of the O1-type stacking within most of the O3 layer stacking configurations. Further sliding of the layers occurs when additional lithium ions desorb from the remaining part of the interlayer region. When the lithium ions are almost completely desorbed, the remaining part of the lattice can be deformed into an ordered hexagonal lattice with an ordered O1-type layer stacking configuration, and the repeating unit is a single NiO2 layer with AB oxygen filling as shown in Figure 5B. A typical XRD pattern of stoichiometric alpha-delithiated layered nickel oxide is shown in Figure 3 (bottom). The XRD pattern of stoichiometric alpha-delithiated layered nickel oxide is similar to that of the corresponding stoichiometric lithium nickelate precursor, with an expected peak shift corresponding to the removal of most of the lithium ions and a slight expansion of the interlayer spacing resulting from the increase in the electrostatic repulsive force between the NiO2 layers.

[0039] General formula Li 1-a Ni 1+aIn the case of O2 and non-stoichiometric lithium nickelate having 0.02 ≦ a ≦ 0.2, excess nickel can occupy the lithium sites in the intermediate layer. The presence of excess nickel can be determined by ICP elemental analysis. The presence of nickel in the lithium sites of the intermediate layer can also be detected by Rietveld analysis of the XRD pattern of non-stoichiometric lithium nickelate. The XRD pattern of non-stoichiometric lithium nickelate compared with the XRD pattern of stoichiometric lithium nickelate is shown in Fig. 2.

[0040] Nickel ions present in the intermediate layer of the non-stoichiometric lithium nickelate precursor generally exist in the intermediate layer of the inductive alpha delithiated layered nickel oxide and finally in the intermediate layer of the non-stoichiometric beta delithiated layered nickel oxide. The oxidation state of the nickel ions in the intermediate layer of lithium nickelate is considered to be Ni(II) based on the ionic radius constraint of the octahedral lithium sites. Although not intended to be bound by theory, when nickel is present in the intermediate layer, even after almost all of the lithium ions have desorbed, the Ni-O bond between the adjacent NiO2 layers is strong, so it is considered that the O3-type layered structure is stabilized by locally suppressing the sliding of the NiO2 layers relative to each other. An example of an O1-type lattice having O3-type stacking defects is shown in Fig. 5C. The atomic fraction of Ni(II) ions present in the intermediate layer of the alpha delithiated layered nickel oxide ranges from about 0.03 to about 0.15, and the atomic fraction of the residual lithium ions present in the intermediate layer ranges from about 0.05 to 0.12.

[0041] Alpha-depleted lithium layered nickel oxide has a high electrochemical potential value and is known to react with an alkaline electrolyte aqueous solution to generate oxygen gas through an oxygen evolution reaction (OER). In addition, the discharge capacity of a battery containing such alpha-depleted lithium layered nickel oxide as an electrochemically active cathode material usually decreases due to self-discharge by OER. When oxygen gas is generated during storage of a closed battery, the internal pressure rises, and if the pressure is high enough, it can cause electrolyte leakage or release. In addition, by consuming water through OER, the amount of moisture present in the cell available for the electrochemical discharge reaction that consumes water to generate protons and hydroxide ions decreases, thereby limiting the accessible discharge capacity of the battery compared to the theoretical capacity. By treating alpha-depleted lithium layered nickel oxide with an alkaline hydroxide solution, the alpha-depleted lithium layered nickel oxide can be stabilized, the rate of OER can be substantially reduced, and the capacity retention after storage can be enhanced. When alpha-depleted lithium layered nickel oxide is treated with an alkaline hydroxide aqueous solution, alkali cations and water molecules are introduced into the intermediate layer of the alpha-depleted lithium oxide structure.

[0042] When an alpha delithiated layered nickel oxide having an atomic fraction of Ni(II) of about 0.03 to about 0.15 (i.e., non-stoichiometric) in the intermediate layer with respect to the total nickel content is treated with an alkaline hydroxide solution, insertion of alkali metal and water molecules into the intermediate layer will introduce additional stacking defects into the structure of the non-stoichiometric alpha delithiated layered nickel oxide. The material containing alkali metal and water, as well as other stacking defects, is called non-stoichiometric beta delithiated layered nickel oxide. Although not intending to be bound by theory, during treatment with an alkaline hydroxide solution, it is considered that the O3-type stacking structure of the alpha delithiated layered nickel oxide is converted into an ordered O1-type stacking structure in which O3-type layer stacking defects are present within the bulk-ordered O1-type lattice. In addition, during treatment with an alkaline hydroxide solution, alkali metal ions accompanied by water molecules are also inserted into the ordered O1-type lattice, forming another type of area stacking defect containing a gamma nickel oxyhydroxide-like layer (γ-NiOOH-like) having a larger spacing (e.g., 11 - 12 Å) between NiO2 layers compared to the spacing between O3-type layers and O1-type layers (about 4.7 Å and 7.2 Å, respectively). The γ-NiOOH-like stacking defect has a P3-type layer stacking structure, and the repeating unit contains three NiO2 layers with oxygen in the stacking order of AB BC CA. Furthermore, it is considered that nucleation of the γ-NiOOH-like layer occurs near the O3-type layer stacking defect, resulting in structural stabilization by minimizing the strain energy at the interface between the O3-type layer stacking defect and the ordered O1-type lattice. The characteristic XRD pattern of the non-stoichiometric beta delithiated layered nickel oxide is shown in Figure 4. The presence of the γ-NiOOH-like layer stacking defect is evidenced by a broad seventh peak appearing at about 11° to 12° 2θ in the XRD pattern of the non-stoichiometric beta delithiated layered nickel oxide. The typical lattice constants of the beta delithiated layered nickel oxide were determined as follows by refinement of the XRD pattern. a = 2.839 Å, c = 14.324 Å (space group: R-3m).

[0043] In contrast, when a nominal stoichiometric alpha delithiated layered nickel oxide having an atomic fraction of Ni(II) of less than about 0.03, or less than about 0.02, in the intermediate layer with respect to the total nickel content is treated with an alkaline hydroxide solution, the alpha delithiated layered nickel oxide is converted almost completely to highly crystalline gamma nickel oxyhydroxide (γ-NiOOH), rather than to a non-stoichiometric beta delithiated layered nickel oxide. As shown in FIG. 4 (bottom), the powder XRD pattern of the non-stoichiometric beta delithiated layered nickel oxide can be easily distinguished from the powder XRD pattern of gamma nickel oxyhydroxide. The lower XRD pattern shown in FIG. 4 was obtained from gamma nickel oxyhydroxide prepared according to the synthesis method described by Arai et al. (Electrochimica Acta 50 (2005) 1821-1828; Solid State Ionics, 80 (1995) 261-269). This XRD pattern corresponds to the XRD pattern of the gamma nickel oxyhydroxide material prepared by Arai (shown in FIG. 1e of Arai), confirming that the product of the KOH treatment of the delithiated lithium nickel oxide prepared from stoichiometric lithium nickel oxide is the same gamma nickel oxyhydroxide material prepared by Arai et al. (Electrochimica Acta 50 (2005) 1821-1828).

[0044] Surprisingly, the non-stoichiometric beta delithiated layered nickel oxide prepared from non-stoichiometric lithium nickelate provides one or more advantages including, but not limited to, a decrease in oxygen evolution rate, a decrease in self-discharge, and an increase in capacity retention when provided as an electrochemically active cathode material in an alkaline battery, compared to the alpha delithiated layered nickel oxide active material prepared from stoichiometric or non-stoichiometric lithium nickelate. For example, the non-stoichiometric beta delithiated layered nickel oxide has an oxygen evolution rate of about 50% or less of the oxygen evolution rate of the corresponding alpha delithiated layered nickel oxide precursor when immersed in an alkaline KOH electrolyte solution, as shown in Table 3. In contrast, non-stoichiometric lithium nickelate and the alpha and beta delithiated layered nickel oxides prepared therefrom are generally not suitable for use as cathode active materials in non-aqueous lithium-ion rechargeable batteries. In particular, the presence of Ni(II) ions in the interlayer region of non-stoichiometric lithium nickelate and the alpha and beta delithiated layered nickel oxides prepared therefrom causes a decrease in the distance between the NiO2 layers. Such a decrease in spacing can impede both the rate and extent of lithium desorption and reinsertion, thereby potentially limiting the total discharge capacity and rate capability of non-aqueous lithium-ion secondary batteries.

[0045] The experimentally measured XRD patterns of non-stoichiometric beta delithiated layered nickel oxide can be simulated using the DIFFaX computer program. The amounts of O3-type stacking faults and gamma NiOOH-like stacking faults present in the ordered O1-type stacking configuration can be statistically varied to estimate the relative amounts of each stacking type that must be present to achieve the relative intensities, peak shapes, and FWHM values of the peaks in the experimentally measured XRD pattern. The DIFFaX program calculates the diffraction intensity vs. 2θ for a given type of stacking configuration assuming a virtual stacking structure model. The XRD pattern can be simulated by introducing increases in the levels of both O3-type stacking faults and gamma nickel oxyhydroxide-like layers into the ordered O1-type oxygen filling model. The simulated diffraction pattern can be refined using the Rietveld analysis to identify the defect structure model that provides the best match to the experimental diffraction pattern. The transition probabilities of the O3-type and gamma nickel oxyhydroxide-like defects used to generate the simulated diffraction pattern that best matches the experimental diffraction pattern can be converted to stacking fractions.

[0046] Using, for example, scanning transmission electron microscope (STEM) imaging as shown in FIG. 6A, and convergent beam electron diffraction (CBED) of individual crystallites as shown in, for example, FIG. 6B, the presence of local stacking defects in the bulk phase having a characteristic layer stacking structure can be easily detected. Specifically, CBED measurements and STEM lattice imaging of individual crystallites of non-stoichiometric beta delithiated layered nickel oxide particles can reveal the presence of low levels of a second (and third) layer stacking structure as stacking defects in the majority of the stacking structures of the bulk phase layered structure. Stacking defects are revealed in the STEM lattice image as a sudden change in the periodicity of the lattice fringes and as a corresponding change in the column spacing of the spots in the electron diffraction pattern. In the case of non-stoichiometric lithium nickelate, the presence of extra spots along the c-axis (compared to nominally stoichiometric lithium nickelate) is consistent with the presence of Ni ions in the interlayer regions having different orders along the c-axis. In the case of non-stoichiometric beta delithiated layered nickel oxide, there is evidence of the presence of an ordered O1-type stacking structure with an inter-column spacing of 7.2 angstroms and a region with an inter-column spacing of 4.7 angstroms corresponding to O3-type layer stacking defects. Furthermore, O3-type defects can be dispersed or present in groups in the O1-type lattice.

[0047] The simulated XRD pattern of the non-stoichiometric β-delithiated layered nickel oxide generated by the DIFFaX program is shown in Figure 7B and can be compared with the corresponding experimentally measured XRD pattern of Figure 7A. As described above, the stacking fraction can be determined using the simulated XRD pattern. The non-stoichiometric β-delithiated layered nickel oxide has a layered structure characterized by a lattice containing multiple NiO2 layers, and the NiO2 lattice includes an ordered O1-type layer stacking configuration, at least one O3-type layer stacking defect, and at least one γ-nickel oxyhydroxide-like layer stacking defect. The values of the layer fractions of the ordered O1-type, O3-type, and γ-nickel oxyhydroxide-type stackings in the lattice structure of the non-stoichiometric β-delithiated layered nickel oxide that provides a high discharge capacity in an alkaline electrochemical cell can have characteristic ranges. In particular, the NiO2 lattice can include an ordered O1-type layer stacking of about 60% to about 95% based on all layers, such as about 65% to about 95%, about 60% to about 85%, about 70% to about 90%, about 85% to about 95%, about 75% to about 90%, about 80% to about 90%, or about 84% to about 88%, determined using the DIFFaX program. The NiO2 lattice of the non-stoichiometric β-delithiated layered nickel oxide can include an O3-type layer stacking defect of about 2% to about 40% based on all layers, such as about 2% to about 35%, about 2% to about 15%, about 2% to about 10%, about 4% to about 30%, about 4% to about 25%, about 6% to about 20%, about 6% to about 15%, about 7% to about 12%, about 7% to about 11%, about 15% to about 40%, about 25% to about 40%, or about 35% to about 40%, determined using the DIFFaX program. The NiO2 lattice of the non-stoichiometric β-delithiated layered nickel oxide can include a γ-NiOOH-like layer stacking defect of about 2% to about 5% based on all layers, such as about 2%, about 3%, about 4%, or about 5% of γ-NiOOH-like layer stacking defects, determined using the DIFFaX program.The characteristic defect structure of non-stoichiometric beta-delithiated layered nickel oxide can be substantially defined by the amount of Ni(II) ions in the lithium layer and the range of the fraction of O1-type layer stacking structure, O3-type layer stacking defects, and gamma nickel oxyhydroxide-like layer stacking defects that are statistically distributed in the crystal lattice.

[0048] Therefore, a method for identifying and characterizing non-stoichiometric beta-delithiated layered nickel oxide that can provide a high discharge capacity when included in the cathode of a primary alkaline battery includes the analysis of X-ray diffraction and electron diffraction data using the DIFFaX program for simulating experimental diffraction patterns using a structural model. For example, to determine whether non-stoichiometric beta-delithiated layered nickel oxide includes an ordered O1-type layer stacking structure of about 60 to 95%, O3-type layer stacking defects of about 2 to 40%, and about 2 to about 5% of gamma nickel oxyhydroxide-like layers, a structural model can be developed to characterize one or more ordered layer stacking structures and plane defects present in the non-stoichiometric beta-delithiated layered nickel oxide.

[0049] Non-stoichiometric beta-delithiated layered nickel oxide can be prepared from non-stoichiometric alpha-delithiated layered nickel oxide prepared from non-stoichiometric lithium nickelate.

[0050] The non-stoichiometric lithium nickelate precursor can have the formula Li 1-a Ni 1+a O2, where 0.02 ≦ a < 0.2. Lithium nickelate can be doped with a metal M selected from among alkaline earth metals, transition metals, non-transition metals, and any combination thereof. The metal-doped lithium nickelate has the formula Li 1-a Ni 1+a-z M zIt can have O2, where 0.02 ≦ a < 0.2 and 0 ≦ z < 0.2. Without intending to be bound by theory, when non-stoichiometric lithium nickelate having an amount of M of 20% or more of the amount of nickel is used as a starting material for non-stoichiometric alpha delithiated layered nickel oxide, if the obtained non-stoichiometric alpha delithiated layered nickel oxide is treated with an alkaline solution, it is considered that non-stoichiometric beta delithiated layered nickel oxide will not be formed, but instead gamma nickel oxyhydroxide will be formed. Further, when lithium nickelate is stoichiometric lithium nickelate (i.e., Li 1-a Ni 1+a O2, 0 ≦ a < 0.02), if the alpha delithiated layered nickel oxide prepared therefrom is treated with an alkaline solution, it is considered that gamma nickel oxyhydroxide will be formed instead of non-stoichiometric beta delithiated layered nickel oxide.

[0051] Non-stoichiometric alpha delithiated layered nickel oxide has the chemical formula Li x H w Ni 1-aIt constitutes O2, where 0.02 ≦ x ≦ 0.2, 0 ≦ w ≦ 0.2, and 0.02 ≦ a ≦ 0.2. Methods for forming non-stoichiometric alpha delithiated layered nickel oxides are well-known in the art. Non-stoichiometric lithium nickelate can be chemically oxidized to form non-stoichiometric alpha delithiated layered nickel oxides. Suitable chemical oxidants for forming alpha delithiated layered nickel oxides from lithium nickelate include, but are not limited to, sodium hypochlorite, sodium persulfate, potassium persulfate, ammonium persulfate, sodium permanganate, potassium permanganate, sodium dichromate, potassium dichromate, ozone gas, chlorine gas, bromine gas, sulfuric acid, hydrochloric acid, and nitric acid. Alpha delithiated layered nickel oxides can further contain a metal M selected from among alkaline earth metals, transition metals, non-transition metals, and any combination thereof. Non-stoichiometric alpha delithiated layered nickel oxides containing a metal dopant M can be prepared from metal-doped non-stoichiometric lithium nickelate precursors. Additionally, the interlayer region of the alpha delithiated layered nickel oxide contains Ni(II) ions with an atomic fraction approximately the same as that within the interlayer region of the lithium nickelate precursor.

[0052] When lithium nickelate is treated with strong mineral acids, Ni(III) ions undergo an acid-promoted disproportionation reaction to form equimolar amounts of soluble Ni(II) and insoluble Ni(IV). This disproportionation reaction can be summarized as Equation 1 as follows. LiNiO2 + 2yH2SO4 → (1 - y)Li (1-2y) / (1-y) NiO2 + yNiSO4 + yLi2SO4 + 2yH2O (0 ≦ y ≦ 1 / 2) (1) The Ni(II) species is soluble and dissolves in acidic aqueous solutions, while the Ni(IV) species is insoluble and remains to maintain the layered crystal lattice structure.

[0053] Non-stoichiometric beta delithiated layered nickel oxides have the chemical formula Li x A y Ni 1+a-z M zIt constitutes O2·nH2O, where x ranges from about 0.02 to about 0.20, y ranges from about 0.03 to about 0.20, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, n ranges from about 0 to about 1, A includes alkali metals including potassium, rubidium, cesium, and any combination thereof, and M includes alkaline earth metals, transition metals, non-transition metals, and any combination thereof. The non-stoichiometric beta delithiated layered nickel oxide is prepared by treating the non-stoichiometric alpha delithiated layered nickel oxide with an alkali solution containing an alkali metal salt. The alkali solution is not particularly limited and can be selected from a potassium salt solution, a rubidium salt solution, a cesium salt solution, or any combination thereof. The alkali solution can be prepared from an alkali salt and water, for example, an alkali hydroxide solution. The concentration of the alkali salt in the alkali solution must be sufficient to achieve complete conversion of the non-stoichiometric alpha delithiated layered nickel oxide to the non-stoichiometric beta delithiated layered nickel oxide. In some embodiments, the concentration of the alkali salt in the solution can be in the range of about 0.5M to about 10M. In some embodiments, the alkali solution contains at least one of potassium hydroxide, cesium hydroxide, and rubidium hydroxide provided at a concentration of about 0.5M to about 10M. The non-stoichiometric alpha delithiated layered nickel oxide can be provided as a free-flowing powder. The non-stoichiometric alpha delithiated layered nickel oxide powder and the alkali solution can be combined at a weight ratio of about 5:1 to about 1:2, or about 4:1 to about 1:2, or about 3:1 to about 1:1, for example, about 3:1, about 2:1, or about 1:1.

[0054] The non-stoichiometric alpha delithiated layered nickel oxide can be treated with an alkaline solution for a period sufficient to convert the non-stoichiometric alpha delithiated layered nickel oxide completely to non-stoichiometric beta delithiated layered nickel oxide. The non-stoichiometric alpha delithiated layered nickel oxide and the alkaline solution can first be stirred at ambient temperature for 5 to 15 minutes to ensure proper mixing and wetting. After mixing the non-stoichiometric alpha delithiated layered nickel oxide and the alkaline solution, the mixture is held at ambient temperature for 2 to 24 hours. Optionally, the mixture can also be stirred for 2 to 24 hours. Complete conversion to non-stoichiometric beta delithiated layered nickel oxide can be determined by analyzing the powder X-ray diffraction pattern. For example, when the non-stoichiometric alpha delithiated layered nickel oxide is converted to non-stoichiometric beta delithiated nickel oxide, the intensity of the peak pattern at about 18° to 20° 2θ in the X-ray diffraction pattern of the non-stoichiometric alpha delithiated layered nickel oxide decreases, and very broad peaks grow in the non-stoichiometric beta delithiated layered nickel oxide X-ray diffraction pattern at about 14.9° to about 16.0° 2θ, and about 21.3° to about 22.7° 2θ. Thus, at complete conversion to non-stoichiometric beta delithiated nickel oxide, the powder X-ray diffraction pattern will have broad peaks with greater intensity than in the powder X-ray diffraction pattern of the non-stoichiometric alpha delithiated layered nickel oxide precursor at about 10.8° to about 12.0° 2θ, about 14.9° to about 16.0° 2θ, and about 31.3° to about 22.7° 2θ, and there will be no peaks with significant intensity in the range of about 18° to 20° 2θ. The resulting non-stoichiometric beta delithiated layered nickel oxide can be repeatedly washed with deionized water until the pH of the filtrate from the wash is about 10. The solid powder can be collected and dried in air at about 70 °C for about 12 to 20 hours.

[0055] In an alkaline battery, the electrochemically active cathode material decreases during discharge, and water from the alkaline electrolyte in the battery is consumed simultaneously. As a result, hydroxide ions are formed, and protons are inserted into the structure of the electrochemically active cathode material. For example, a conventional alkaline battery may include electrolytic manganese dioxide (EMD) as the electrochemically active cathode material. In such a conventional alkaline battery, 1 mole of water can be consumed per mole of manganese present in the 4+ oxidation state, which can be reduced to manganese in the 3+ oxidation state by a one-electron reduction process. For example, a non-conventional alkaline battery may include non-stoichiometric beta-lithium-depleted layered nickel oxide as the electrochemically active cathode material. The non-stoichiometric beta-lithium-depleted layered nickel oxide has, for example, the chemical formula Li 0.07 K 0.13 Ni 1.11It may have O2·0.63H2O. In such a non-conventional alkaline battery, up to 2 moles of water can be consumed per mole of nickel present in the 4+ oxidation state, which can be reduced to nickel in the 2+ oxidation state by a two-electron reduction process. Additionally, 1 mole of water can be consumed per mole of nickel present in the 3+ oxidation state, which can be reduced to nickel in the 2+ oxidation state by a one-electron reduction process. Thus, the electrochemical discharge of a battery containing non-stoichiometric beta-delithiated layered nickel oxide may require more than 1 mole of water per mole of nickel to achieve a complete discharge. Additionally, an excessive amount of water may be required to minimize the polarization of the anode during discharge and to replenish the water consumed by self-discharge during battery storage. The excessive amount of water that may be required depends on the specific chemical composition of the non-stoichiometric beta-delithiated layered nickel oxide and the relative amounts of nickel in the 4+ and 3+ oxidation states. Water can be introduced into the battery as moisture in the non-stoichiometric beta-delithiated layered nickel oxide via the alkaline electrolyte aqueous solution. The alkaline electrolyte can be distributed throughout the battery. The total amount of moisture present in the battery can be increased in various ways. For example, the amount of moisture may be increased by increasing the total amount of alkaline electrolyte added to the battery. Further, the amount of moisture in the battery may be increased by decreasing the potassium hydroxide concentration of the electrolyte solution. In contrast, in a conventional alkaline battery, it is desirable to add a minimum total amount of electrolyte to the battery to maximize the available internal volume for the electrochemically active electrode material.

[0056] The cathode 12 can include non-stoichiometric beta delithiated layered nickel oxide as an electrochemically active cathode material. As used herein, "non-stoichiometric beta delithiated layered nickel oxide" refers to non-stoichiometric delithiated layered nickel oxide isolated in the "beta" form. Thus, for example, when non-stoichiometric beta delithiated layered nickel oxide is provided as an electrochemically active cathode material, the non-stoichiometric beta delithiated layered nickel oxide includes less than 5 wt%, less than 3 wt%, less than 1 wt%, or less than 0.5 wt% residual non-stoichiometric alpha delithiated layered nickel oxide based on the total weight of the electrochemically active cathode material of the delithiated layered nickel oxide. Similarly, in the cells described herein that include non-stoichiometric beta delithiated layered nickel oxide, non-stoichiometric beta delithiated layered nickel oxide is provided from the start.

[0057] The cathode 12 may also include at least one or more additional electrochemically active cathode materials. The additional electrochemically active cathode materials can include manganese oxide, manganese dioxide, electrolytic manganese dioxide (EMD), chemical manganese dioxide (CMD), high performance electrolytic manganese dioxide (HP EMD), lambda manganese dioxide, gamma manganese dioxide, and any combination thereof. Other electrochemically active cathode materials include, but are not limited to, silver oxide, nickel oxide, nickel oxyhydroxide, copper oxide, silver copper oxide, silver nickel oxide, bismuth oxide, oxygen, and any combination thereof. Nickel oxyhydroxide can include beta nickel oxyhydroxide, gamma nickel oxyhydroxide, intergrowth of beta nickel oxyhydroxide and / or gamma nickel oxyhydroxide, and nickel oxyhydroxide coated with cobalt oxyhydroxide. Nickel oxyhydroxide coated with cobalt oxyhydroxide can include cobalt oxyhydroxide coated beta nickel oxyhydroxide, cobalt oxyhydroxide coated gamma nickel oxyhydroxide, and / or cobalt oxyhydroxide coated intergrowth of beta nickel hydroxide and nickel oxyhydroxide.

[0058] In an embodiment, the electrochemically active material of the cathode 12 has a general chemical formula Li x A y Ni 1+a-z M zContaining at least 10 wt% of non-stoichiometric beta delithiated layered nickel oxide with O2·nH2O, where x ranges from about 0.03 to about 0.12, y ranges from about 0.03 to about 0.20, a ranges from about 0.02 to about 0.2, z ranges from about 0 to about 0.2, n ranges from about 0 to about 1, A includes alkali metals, M includes alkaline earth metals, transition metals, non-transition metals, and any combination thereof, and the remaining portion of the electrochemically active cathode material includes one or more of manganese oxide, manganese dioxide, electrolytic manganese dioxide (EMD), chemical manganese dioxide (CMD), high-performance electrolytic manganese dioxide (HP EMD), lambda manganese dioxide, or gamma manganese dioxide. In embodiments, the electrochemically active material of cathode 12 includes at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 55 wt%, at least 60 wt%, at least about 70 wt%, or at least about 75 wt% of non-stoichiometric beta delithiated layered nickel oxide, based on the total weight of the electrochemically active cathode material, for example, within the range of about 10 wt% to about 90 wt%, about 10 wt% to about 80 wt%, about 20 wt% to about 70 wt%, about 30 wt% to about 60 wt%, about 40 wt% to about 60 wt%, or about 50 wt% based on the total weight of the electrochemically active cathode material. In embodiments, the electrochemically active material of cathode 12 includes about 40 wt% to about 60 wt% of non-stoichiometric beta delithiated nickel oxide based on the total weight of the electrochemically active cathode material and about 60 wt% to about 40 wt% of one or more of manganese oxide, manganese dioxide, electrolytic manganese dioxide (EMD), chemical manganese dioxide (CMD), high-performance electrolytic manganese dioxide (HP EMD), lambda manganese dioxide, or gamma manganese dioxide based on the total weight of the electrochemically active cathode material.Combinations of from about 10 wt% to about 60 wt%, for example 20 wt% or 50 wt% of non-stoichiometric beta delithiated layered nickel oxide and the remainder of the electrochemically active cathode material including electrolytic manganese dioxide (EMD) have been found to provide unexpectedly advantageous battery performance in both high rate and low rate applications.

[0059] Cathode 12 may include a conductive additive such as carbon and optionally a binder. Cathode 12 may also include other additives. Carbon may increase the conductivity of cathode 12 by facilitating electron transport within the solid structure of cathode 12. The carbon may be graphite such as natural graphite, synthetic graphite, oxidation resistant graphite, graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon fibers, carbon nanofibers, carbon nanoribbons, carbon nanoplatelets, and mixtures thereof. The amount of carbon in the cathode is relatively low, for example less than about 12%, less than about 10%, less than about 9%, less than about 8%, less than about 6%, less than about 5%, less than about 3.75%, or less than about 3.5%, for example from about 3.0 wt% to about 5 wt% or from about 2.0 wt% to about 3.5% is preferred. A low carbon level allows more of the electrochemically active cathode material to be included in cathode 12 without increasing the volume of cathode 12 or reducing the void volume (which must be maintained above a certain level to prevent excessive internal pressure build-up when gas is generated within the cell) within battery 10. Graphites suitable for use within a battery, for example within a cathode, are, for example, Timrex MX-15, SFG-15, MX-25, all of which are available from Imerys Graphite and Carbon (Bodio, Switzerland). For highly reactive cathode active materials such as non-stoichiometric beta delithiated layered nickel oxide, oxidation resistant graphites such as SFG-15, SFG-10, and SFG-6 can be used.

[0060] The cathode 12 can include an optional binder. As used herein, "binder" refers to a polymer material that provides cohesiveness to the cathode and does not contain graphite. Examples of optional binders that can be used in the cathode 12 include polyethylene, polyacrylic acid, or fluorocarbon resins such as PVDF and PTFE. The optional binder for use in the cathode 12 can be, for example, COATHYLENE HA-1681, available from E.I. du Pont de Nemours and Company (Wilmington, Delaware, USA). Examples of other cathode additives are described, for example, in U.S. Patent Nos. 5,698,315, 5,919,598, 5,997,775, and 7,351,499. In some embodiments, the cathode 12 is substantially binder-free. As used herein, "substantially binder-free" means that the cathode contains less than about 5 wt%, less than about 3 wt%, or less than about 1 wt% of the binder.

[0061] The content of the electrochemically active cathode material in the cathode 12 can be referred to as the cathode filling amount. The filling amount of the cathode 12 can vary depending on the electrochemically active cathode material used in the battery 10 and the size of the battery 10. For example, a single 3-cell battery equipped with beta-depleted lithium layered nickel oxide as the electrochemically active cathode material can have a cathode filling amount of at least about 6 grams of beta-depleted lithium layered nickel oxide. The cathode filling amount can be, for example, at least about 7 grams of non-stoichiometric beta-depleted lithium layered nickel oxide. The cathode filling amount can be, for example, non-stoichiometric beta-depleted lithium layered nickel oxide from about 7.2 grams to about 11.5 grams. The cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 8 grams to about 10 grams. The cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 8.5 grams to about 9.5 grams. The cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 9.5 grams to about 11.5 grams. The cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 10.4 grams to about 11.5 grams. In a single 4-cell battery, the cathode filling amount can be at least about 3 grams of non-stoichiometric beta-depleted lithium layered nickel oxide as the electrochemically active cathode material. The cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 3 grams to about 5 grams. The cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 3.5 grams to about 4.5 grams. The cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 3.9 grams to about 4.3 grams. In a single 6-cell battery, the cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 1.5 grams to about 2.5 grams as the electrochemically active cathode material. In a single 2-cell battery, the cathode filling amount can be non-stoichiometric beta-depleted lithium layered nickel oxide from about 27.0 grams to about 40.0 grams, for example about 33.5 grams, as the electrochemically active cathode material.In a single battery, the cathode charge can be a non-stoichiometric beta-delithiated layered nickel oxide electrochemically active cathode material from about 60.0 grams to about 84.0 grams, such as about 72.0 grams.

[0062] Cathode components such as (one or more) active cathode materials, carbon particles, binders, and any other additives can be combined with a liquid such as an aqueous potassium hydroxide electrolyte, mixed, pressed into pellets for use in assembling battery 10. For optimal cathode pellet processing, the cathode pellets generally preferably have a moisture level in the range of about 2 wt% to about 5 wt%, or about 2.8 wt% to about 4.6 wt%. The pellets are placed within housing 18 during the assembly of battery 10 and are typically re-pressed to form a uniform cathode assembly within housing 18. The cathode pellets can have a cylindrical shape including a central hole. The size of the pellets can vary depending on the size of the battery in which the pellets are used internally, such as single 3, single 4, single 6, single 2, single 1. The central hole can define the inner diameter (ID) of the pellet. The inner diameter of the pellet for a single 3 battery can be, for example, from about 9.1 mm to about 9.9 mm. The inner diameter of the pellet for a single 3 battery can be, for example, from about 9.3 mm to about 9.7 mm. The inner diameter of the pellet for a single 4 battery can be, for example, from about 6.6 mm to about 7.2 mm. The inner diameter of the pellet for a single 4 battery can be, for example, from about 6.7 mm to about 7.1 mm. The inner diameter of the pellet for a single 6 battery can be, for example, from about 5 mm to about 5.5 mm. The inner diameter of the pellet for a single 2 battery can be, for example, from about 16 mm to about 19 mm. The inner diameter of the pellet for a single 1 battery can be, for example, from about 21 mm to about 25 mm.

[0063] The cathode 12 will have a porosity that can be calculated during cathode manufacturing. The porosity of the cathode 12 can be from about 20% to about 40%, from about 22% to about 35%, for example about 26%. Since the porosity of the cathode 12 in the battery 10 can change over time, due to, among other things, cathode expansion associated with wetting of the cathode electrolyte and discharge of the battery 10, the porosity of the cathode 12 can be calculated during manufacturing, for example after treatment of the cathode pellets. The porosity of the cathode 12 can be calculated as follows. The true density of each solid cathode component can be obtained from a reference, such as Lange’s Handbook of Chemistry (16th ed. 2005). The solids weight of each cathode component is defined by the battery design. Dividing the solids weight of each cathode component by the true density of each cathode component can determine the cathode solid volume. The volume occupied by the cathode 12 in the battery 10 is also defined by the battery design. The volume occupied by the cathode 12 can be calculated by a computer-aided design (CAD) program. The porosity can be determined by the following formula. Cathode porosity = [1 - (cathode solid volume ÷ cathode volume)] × 100

[0064] For example, the cathode 12 of a single AA battery can include about 9.0 grams of non-stoichiometric beta delithiated layered nickel oxide and about 0.90 grams of graphite (BNC-30) as solids in the cathode 12. The true densities of the non-stoichiometric beta delithiated layered nickel oxide and graphite are about 4.9 g / cm 3 and about 2.15 g / cm 3 respectively. Dividing the weight of the solids by their respective true densities gives the volume occupied by about 1.8 cm 3 of non-stoichiometric beta delithiated layered nickel oxide and the volume occupied by about 0.42 cm 3 of graphite. The total solid volume is about 2.2 cm 3 The battery designer can select the volume occupied by the cathode 12 to be about 3.06 cm 3 Using the above equation [1 - (2.2 cm 3 ÷ 3.06 cm 3)]When calculating the cathode porosity according to [the given method], a cathode porosity of approximately 0.28, i.e., 28%, is obtained.

[0065] The anode 14 can be formed of at least one electrochemically active anode material, a gelling agent, and a small amount of additives such as an organic and / or inorganic gas generation inhibitor. The electrochemically active anode material can include zinc, zinc oxide, zinc hydroxide, metal hydrides such as AB5(H), AB2(H), A2B7(H), alloys thereof, and any combination thereof.

[0066] The content of the electrochemically active anode material in the anode 14 can be referred to as the anode filling amount. The filling amount of the anode 14 can vary depending on the electrochemically active anode material used in the battery and the size of the battery. For example, a single 3-cell battery with an electrochemically active anode material of zinc can have an anode filling amount of at least about 3.3 grams of zinc. The anode filling amount can be, for example, at least about 3.5 grams, about 3.7 grams, about 3.9 grams, about 4.1 grams, about 4.3 grams, or about 4.5 grams of zinc. The anode filling amount can be zinc from about 4.0 grams to about 5.5 grams. The anode filling amount can be zinc from about 4.2 grams to about 5.3 grams. For example, a single 4-cell battery with an electrochemically active anode material of zinc can have an anode filling amount of at least about 1.8 grams of zinc. For example, the anode filling amount can be zinc from about 1.8 grams to about 2.5 grams. The anode filling amount can be, for example, zinc from about 1.9 grams to about 2.4 grams. For example, a single 6-cell battery with an electrochemically active anode material of zinc can have an anode filling amount of at least about 0.6 grams of zinc. For example, the anode filling amount can be zinc from about 0.7 grams to about 1.3 grams. For example, a single 2-cell battery with an electrochemically active anode material of zinc can have an anode filling amount of at least about 9.3 grams of zinc. For example, the anode filling amount can be zinc from about 10.0 grams to about 19.0 grams. For example, a single 1-cell battery with an electrochemically active anode material of zinc can have an anode filling amount of at least about 30.0 grams of zinc. For example, the anode filling amount can be zinc from about 30.0 grams to about 45.0 grams. The anode filling amount can be, for example, zinc from about 33.0 grams to about 39.5 grams.

[0067] Examples of gelling agents that can be used within the anode 14 include polyacrylic acid, polyacrylic acid crosslinked with a polyalkenyl ether of divinyl glycol, a grafted starch material, a salt of polyacrylic acid, carboxymethyl cellulose, a salt of carboxymethyl cellulose (e.g., sodium carboxymethyl cellulose), or combinations thereof. The anode 14 can include a gas generation inhibitor that can include an inorganic material such as bismuth, tin, or indium. Alternatively, the gas generation inhibitor can include an organic compound such as a phosphate ester, an ionic surfactant, or a non-ionic surfactant. The electrolyte can be dispersed throughout the cathode 12, the anode 14, and the separator 16. The electrolyte includes an ion-conductive component in an aqueous solution. The ion-conductive component can be an alkali hydroxide. The hydroxide can be, for example, potassium hydroxide, cesium hydroxide, and any combination thereof. The concentration of the ion-conductive component can be selected according to the design of the battery and its desired performance. The aqueous alkaline electrolyte can include a hydroxide as the ion-conductive component in a solution containing water. The concentration of the alkali hydroxide in the electrolyte can be from about 0.20 to about 0.40, or from about 20% to about 40% by weight of the total electrolyte within the battery 10. For example, the hydroxide concentration of the electrolyte can be from about 0.25 to about 0.32, or from about 25% to about 32% by weight of the total electrolyte within the battery 10. The aqueous alkaline electrolyte can also include zinc oxide (ZnO). ZnO can help suppress zinc corrosion in the anode. The concentration of ZnO included in the electrolyte can be less than about 5% by weight of the total electrolyte within the battery 10. The ZnO concentration can be, for example, from about 1% to about 3% by weight of the total electrolyte within the battery 10.

[0068] For example, the total weight of the aqueous alkaline electrolyte in a AA alkaline battery can be from about 3.0 grams to about 4.4 grams. The total weight of the alkaline electrolyte in an AA battery can be, for example, from about 3.3 grams to about 3.8 grams. The total weight of the alkaline electrolyte in an AA battery can be, for example, from about 3.4 grams to about 3.65 grams. The total weight of the aqueous alkaline electrolyte in a AAA alkaline battery can be, for example, from about 1.0 gram to about 2.0 grams. The total weight of the electrolyte in a AAA battery can be, for example, from about 1.2 grams to about 1.8 grams. The total weight of the electrolyte in a AAA battery can be, for example, from about 1.4 grams to about 1.8 grams. The total weight of the electrolyte in a 6F battery can be from about 0.68 gram to about 1 gram, for example, from about 0.85 gram to about 0.95 grams. The total weight of the electrolyte in a C battery can be from about 11 grams to about 14 grams, for example, from about 12.6 grams to about 13.6 grams. The total weight of the electrolyte in a D battery can be from about 22 grams to about 30 grams, for example, from about 24 grams to about 29 grams.

[0069] Separator 16 includes a wettable or electrolyte-wetted material. A material is said to be wetted by a liquid when the contact angle between the liquid and the surface of the material is less than 90° or when the liquid has a tendency to spread spontaneously over the entire surface of the material, and both conditions usually coexist. Separator 16 can include a single layer or multiple layers of woven or non-woven paper or cloth. Separator 16 can include, for example, a layer of cellophane combined with a layer of non-woven material. Separator 16 can also include an additional layer of non-woven material. Separator 16 can also be formed in situ within battery 10. For example, U.S. Patent No. 6,514,637 discloses such separator materials and potentially suitable methods of their application. The separator material can be thin. Separator 16 can have, for example, a dry material thickness of less than 250 micrometers (microns). Separator 16 can have a dry material thickness from about 50 microns to about 175 microns. Separator 16 can have a dry material thickness from about 70 microns to about 160 microns. Separator 16 can have a basis weight of about 40 g / m2 or may have a basis weight of less than 20. The separator 16 may have a basis weight of from about 15 g / m 2 to about 40 g / m 2 The separator 16 may have a basis weight of from about 20 g / m 2 to about 30 g / m 2 The separator 16 may have an air permeability value. The separator 16 may have an air permeability value as defined by International Organization for Standardization (ISO) standard 2965. The air permeability value of the separator 16 is about 2000 cm 3 / cm 2 / min at 1 kPa to about 5000 cm 3 / cm 2 / min at 1 kPa. The air permeability value of the separator 16 may be from about 3000 cm 3 / cm 2 / min at 1 kPa to about 4000 cm 3 / cm 2 / min at 1 kPa. The air permeability value of the separator 16 may be from about 3500 cm 3 / cm 2 / min at 1 kPa to about 3800 cm 3 / cm 2 / min at 1 kPa.

[0070] The current collector 20 can be manufactured in any shape suitable for a particular battery design by any known method within the art. The current collector 20 may have, for example, a nail-like shape. The current collector 20 may have a cylindrical body and a head located at one end of the cylindrical body. The current collector 20 can be manufactured from a metal, such as zinc, copper, brass, silver, or other suitable material. The current collector 20 may optionally be plated with tin, zinc, bismuth, indium, or another suitable material that exhibits a low electrical contact resistance between the current collector 20 and, for example, the anode 14. The plating material may also exhibit the ability to suppress gas formation when the current collector 20 contacts the anode 14.

[0071] The seal 22 can be prepared by injection molding polymers such as polyamide, polypropylene, polyether urethane, polymer composites, and any combination thereof into a shape of a predetermined dimension. The seal 22 can be manufactured from, for example, nylon 6,6, nylon 6,10, nylon 6,12, nylon 11, polypropylene, polyether urethane, copolymers, composites, and any combination thereof. Exemplary injection molding methods include both the cold runner method and the hot runner method. The seal 22 can include other known functional materials such as plasticizers, crystal nucleating agents, antioxidants, release agents, lubricants, and antistatic agents. The seal 22 can also be coated with a sealant. The seal 22 can be humidified before being used in the battery 10. The seal 22 can have, for example, from about 1.0 weight percent to about 9.0 weight percent of moisture, depending on the seal material. The current collector 20 can be inserted through the seal 22 into the seal 22.

[0072] The end cap 24 can be formed in any shape sufficient to close the battery. The end cap 24 can have, for example, a cylindrical shape or a prismatic shape. The end cap 24 can be formed by pressing a material into a desired shape of appropriate dimensions. The end cap 24 can be manufactured from any suitable material that conducts electrons during discharge of the battery 10. The end cap 24 can be manufactured from, for example, nickel-plated steel or tin-plated steel. The end cap 24 can be electrically connected to the current collector 20. The end cap 24 can be electrically connected to the current collector 20, for example, by welding to the current collector 20. The end cap 24 can also include one or more openings, such as holes, for releasing any gas pressure due to electrolyte leakage or release of the battery caused by an increase in excessive internal pressure. The current collector 20, the seal 22, and the end cap 24 can be collectively referred to as an end cap assembly.

[0073] A battery 10 including a cathode 12 containing non-stoichiometric beta delithiated layered nickel oxide may have an open circuit voltage (OCV) measured in volts. The battery 10 may have an OCV from about 1.7V to about 1.8V. The battery 10 may have an OCV of, for example, about 1.76V.

[0074] A battery including an electrochemically active cathode material of non-stoichiometric beta delithiated layered nickel oxide of the present invention may have improved discharge performance for low, medium, and high drain discharge rates compared to, for example, a conventional alkaline battery. A battery including an electrochemically active cathode material of non-stoichiometric beta delithiated layered nickel oxide of the present invention may have a higher open circuit voltage than a conventional alkaline battery, for example.

[0075] Experimental tests Elemental analysis of the electrochemically active material of beta delithiated layered nickel oxide by ICP-AES Perform elemental analysis by ICP-AES on a sample of the electrochemically active material of non-stoichiometric beta delithiated layered nickel oxide to determine the elemental composition of the sample material. Use a HORIBA Scientific Ultima 2 ICP spectrometer to complete the ICP-AES analysis. Complete the ICP-AES analysis by placing the sample solution in the spectrometer. Prepare the sample solution in a manner that depends on the (one or more) elements to be analyzed.

[0076] For elemental analysis, 0.15 g of the sample material is added to 2 ml of deionized water (DI) and 5 ml of concentrated hydrochloric acid (HCl) to form a first solution. The sample is gently swirled to mix the contents and then placed in a CEM Discover SP-D automatic microwave digestion system. While the sample is being stirred, the microwave system ramps up to 180 °C in 3 minutes and then holds at 180 °C for 4 minutes. The system is set to a maximum power output of 300 W and a pressure set point of 225 PSI. The first solution is added to a 100 ml volumetric flask and diluted to the mark with DI water to form a second solution. The second solution is used for elemental analysis of lithium (Li), potassium (K), and rubidium (Rb) using an ICP-AES spectrometer. 1 mL of the second solution is transferred to a 50 mL centrifuge tube, approximately 2.5 mL of concentrated hydrochloric acid is added to the centrifuge tube, and distilled water is added to the centrifuge tube to bring the total weight of the components in the centrifuge tube to 50 grams, and the components in the centrifuge tube are mixed to form a third solution. The third solution is used for elemental analysis of nickel (Ni) using an ICP-AES spectrometer.

[0077] ICP-AES analysis of the electrochemically active material of non-stoichiometric beta delithiated layered nickel oxide is performed at various wavelengths specific to potassium (K), lithium (Li), nickel (Ni), and rubidium (Rb). For example, the wavelength (λ) for the analysis of potassium (K) in non-stoichiometric beta delithiated layered nickel oxide can be set to approximately 766 nm. For example, the wavelength (λ) for the analysis of lithium (Li) in non-stoichiometric beta delithiated layered nickel oxide can be set to approximately 610 nm. For example, the wavelength (λ) for the analysis of nickel (Ni) in non-stoichiometric beta delithiated layered nickel oxide can be set to approximately 231 nm. For example, the wavelength (λ) for the analysis of rubidium (Rb) in non-stoichiometric beta delithiated layered nickel oxide can be set to approximately 780 nm.

[0078] Table 1 below includes elemental analysis by ICP-AES results for various samples of the electrochemically active material of non-stoichiometric beta delithiated layered nickel oxide and nickel gamma oxyhydroxide materials prepared according to the synthesis methods described by Arai et al. (Electrochimica Acta 50(2005)1821~1828; Solid State Ionics, 80(1995)261~269). The weight percentages of lithium (Li), nickel (Ni), and potassium (K) in the sample materials are reported. Elemental analysis by ICP-AES data is used to determine the chemical composition of non-stoichiometric beta delithiated layered nickel oxide samples and nickel gamma oxyhydroxide materials prepared according to the synthesis methods described by Arai et al. (Electrochimica Acta 50(2005)1821~1828; Solid State Ionics, 80(1995)261~269). Also, elemental analysis by ICP-AES is used to confirm the presence of excess nickel in non-stoichiometric and non-stoichiometric beta delithiated layered nickel oxide compositions.

[0079] Water content by thermogravimetric analysis (TGA) of the electrochemically active material of beta delithiated layered nickel oxide The water content by TGA is completed for samples of the electrochemically active material of non-stoichiometric beta delithiated layered nickel oxide to determine the absorbed / adsorbed water, water of crystallization, and total water content in the sample material. The TGA analysis is completed using a Q5000 analyzer from TA Instruments.

[0080] The TGA analysis is performed by placing approximately 34 mg of the sample on the TGA sample holder. The sample material is heated to a temperature of approximately 800 °C at a rate of 5 °C / min. The heating of the sample is performed in the presence of nitrogen flowing at a rate of, for example, approximately 25 mL / min. The sample weight is measured as a function of time and temperature.

[0081] Table 1 also includes the water content measured by TGA for samples of non-stoichiometric β-delithiated layered nickel oxide. The water content measured by TGA is used to determine the lattice water present in the chemical composition of the electrochemically active material of non-stoichiometric β-delithiated layered nickel oxide. Using the water content measured by TGA, the water physically adsorbed on the surface of non-stoichiometric β-delithiated layered nickel oxide particles can be determined.

Table 1

[0082] Powder X-ray diffraction analysis Powder X-ray diffraction (XRD) analysis was performed on crystalline powder samples using a Bruker D-8 Advance X-ray diffractometer to determine the characteristic XRD diffraction patterns of the crystalline powder samples. Using Cu-Kα radiation and a Sol-X detector (Baltic Scientific Instruments, Riga, Latvia), XRD diffraction patterns of various samples of non-stoichiometric β-delithiated layered nickel oxide and several comparative samples were obtained. A sample material of about 1 gram to about 2 grams was placed in a Bruker sample holder. The sample holder containing the sample material was then placed on the rotating sample stage of the X-ray diffractometer, and then the sample material was irradiated with the Cu-Kα X-ray source of the diffractometer. Using Diffrac-plus software supplied by Bruker Corporation, an XRD pattern was then collected using a step size of 0.02° at 2 seconds / step from 10° 2θ to 80° 2θ. Analysis and refinement of the diffraction pattern were performed using the EVA and Topas data analysis software packages (Bruker AXS Inc.). The XRD pattern of the sample was compared with the reference XRD patterns in the PDF-4+ database (International Centre for Diffraction Data, ICDD).

[0083] Structure model of β-delithiated layered nickel oxide To elucidate the properties of the highly defective layered structure of non-stoichiometric β-lithium-depleted layered nickel oxide, DIFFaX computer simulations were used to reproduce the experimentally measured X-ray diffraction patterns. The DIFFaX program assumes a format in which a crystalline solid can be constructed by stacking layers of planes of atoms (ions), and calculates the X-ray diffraction pattern by integrating the diffraction intensity versus the 2θ diffraction angle for each layer for a given stacking configuration. For non-stoichiometric β-lithium-depleted layered nickel oxide, NiO2 layers were constructed using the same atomic positions as those used to simulate the ideal layered R-3m structure. Next, translation (i.e., stacking) vectors were applied to stack the NiO2 layers along the c-axis direction to introduce the presence of specific types of stacking defects, such as O3, O1, P3. A random distribution of stacking defects was introduced by the simulation. Different stacking vectors were used to introduce specific stacking defects. The probability of applying each stacking vector can be changed until a sufficient match between the calculated X-ray diffraction pattern and the experimental X-ray diffraction pattern is achieved. The fitness of the simulation was evaluated by Rietveld analysis of the simulation pattern versus the experimental pattern.

[0084] Through the analysis of X-ray diffraction patterns, lattice imaging by scanning transmission electron microscopy (STEM), and electron diffraction (CBED) patterns, a detailed structural model was developed to describe the characteristic defect structure of non-stoichiometric β-lithium-depleted layered nickel oxide. The characteristic diffraction peak intensities, peak positions, and peak widths of the experimental X-ray diffraction patterns were simulated using DIFFaX software by introducing an increasing level of O3-type layer stacking defects into an ordered O1-type lattice. The presence of a very small number of O3-type layer stacking defects may also be related to the presence of specific structural (i.e., growth) defects, as well as nickel (II) ions located at lithium ion sites within the intermediate layer. Although not intended to be bound by theory, during the formation of non-stoichiometric β-lithium-depleted layered nickel oxide, Ni to the interlayer sites that were previously occupied by lithium ions in non-stoichiometric α-lithium-depleted layered nickel oxide 2+It is considered that the ordering of the metal-containing layer in the O1-type stacking structure can occur such that the Ni-containing layer aggregates along the c-axis by the migration of ions. As a result, oxygen atoms are cubic close-packed, and the order along the c-axis is not the metal-containing layer order in the case of alpha delithiated layered nickel oxide -O-Li-O-Ni-Li-O-Ni-O-, but rather, for example, -O-Li-O-Ni-O-Ni-O-Li-O-, so that an ordered O1-type lattice can be obtained that includes the superposed order of the metal-containing layers in which two Ni-containing layers separate each Li-containing layer. The formation of adjacent Ni-containing layers is systematic and periodic. Further, it is considered that another type of surface defect can occur by the insertion of alkali ions and water molecules during KOH treatment, and the defect has a layer structure closely related to the layer structure of gamma nickel oxyhydroxide. Gamma nickel oxyhydroxide has been reported to have an AB BC CA oxygen stacking structure (i.e., P3-type stacking). The introduction of this P3-type stacking defect into the ordered O1 lattice was confirmed by the appearance of a broad low-intensity diffraction peak at about 10.8° to about 12.0° 2θ in the simulated X-ray diffraction pattern that exactly matched the corresponding peak in the experimental X-ray diffraction pattern.

[0085] Table 2 summarizes the best fit obtained for the X-ray diffraction pattern simulated by the DIFFaX program and the experimental X-ray diffraction pattern of a non-stoichiometric beta delithiated layered nickel oxide sample prepared from various non-stoichiometric lithium nickel oxide precursors of the above structural model.

Table 2

[0086] The layer fraction of O3-type laminated defects ranges from about 0.02 to about 0.40, the layer fraction of γ-NiOOH-like defects ranges from about 0.02 to about 0.05, and the layer fraction of the dominant ordered O1 stacking structure ranged from about 0.60 to about 0.95. This structural model could successfully explain the non-uniform and abnormal diffraction peak broadening in the characteristic X-ray powder diffraction pattern of a beta delithiated layered nickel oxide sample prepared from a non-stoichiometric alpha delithiated layered nickel oxide by treatment with a potassium hydroxide solution.

[0087] Gas generation by alpha and beta delithiated layered nickel oxides The rate of oxygen generation by non-stoichiometric beta delithiated layered nickel oxide in contact with an alkaline electrolyte solution was determined using a gas generation rate analyzer and compared with the gas generation rate of the corresponding non-stoichiometric alpha delithiated layered nickel oxide precursor. Table 3 shows the total gas pressure as a function of storage time at 40°C. The rate of oxygen generation by non-stoichiometric beta delithiated layered nickel oxide is significantly lower than the rate of oxygen generation by alpha delithiated layered nickel oxide. Specifically, the total oxygen pressure of a sample of non-stoichiometric beta delithiated layered nickel oxide after storage at 40°C for 80 hours was less than 50% of the total oxygen pressure of the corresponding non-stoichiometric alpha delithiated layered nickel oxide precursor.

Table 3

[0088] Thus, Table 3 shows the advantageous reduction of oxygen gas generation of the non-stoichiometric beta delithiated layered nickel oxide according to the present invention compared to the corresponding non-stoichiometric alpha delithiated layered nickel oxide precursor.

[0089] Assembly of a single-alkali primary battery Assemble a conventional AA alkaline battery called Battery A in Table 5 below. Battery A includes an anode, a cathode, a separator, and an aqueous alkaline electrolyte within a cylindrical housing. The anode includes an anode slurry containing 4.27 grams of metallic zinc powder, 1.78 grams of alkaline KOH electrolyte in which approximately 31 wt% KOH and 2.0 wt% ZnO are dissolved in water, 0.026 grams of polyacrylic acid gelling agent, and 0.023 grams of corrosion inhibitor. The cathode includes a mixture of electrolytic manganese dioxide (EMD), graphite, and an aqueous potassium hydroxide electrolyte solution. The cathode includes 10.87 grams of EMD, 0.46 grams of Timrex MX-15 graphite, 0.12 grams of Timrex BNB-90 expanded graphite (Imerys Graphite and Carbon, Bodio, Switzerland), and 0.52 grams of an alkaline KOH electrolyte solution filling. A separator is interposed between the anode and the cathode. The separator is wetted with a preshot of 1.33 grams of alkaline KOH electrolyte solution in which approximately 31 wt% KOH is dissolved in deionized water. The anode, cathode, and separator are inserted into the cylindrical housing. Then the housing is sealed to complete the battery assembly process. Then Battery A is aged at 20 °C for 4 days and a performance test is conducted as described below.

[0090] Assemble the experimental AA battery, referred to as Battery B, in Table 4 below. Battery B includes an anode, a cathode, a separator, and an electrolyte within a cylindrical housing. The anode includes an anode slurry containing 5.17 grams of metallic zinc powder, 2.17 grams of an alkaline KOH electrolyte in which approximately 27 wt% KOH and 1.7 wt% ZnO are dissolved in deionized water, 0.038 grams of a polyacrylic acid gelling agent, and 0.01 grams of a corrosion inhibitor. The cathode includes a mixture of non-stoichiometric beta delithiated layered nickel oxide, graphite, and an aqueous potassium hydroxide electrolyte solution. The cathode includes 9.54 grams of beta delithiated layered nickel oxide, 0.78 grams of Timrex MX-15 graphite (Imerys Graphite and Carbon, Bodio, Switzerland), and 0.52 grams of a filling of KOH electrolyte solution. Interpose a separator between the anode and the cathode. Wet the separator with a pre-shot of approximately 1.00 gram of an alkaline KOH electrolyte solution in which approximately 5.5 wt% KOH is dissolved in deionized water. Insert the anode, cathode, and separator into the cylindrical housing. Then seal the housing to complete the battery assembly process.

[0091] Then age Battery B at 20 °C for 4 days and perform a performance test as described below.

Table 4

[0092] Performance Test of Assembled AA Alkaline Primary Battery Before the performance test, age the battery at approximately 20 °C for 4 days. After 4 days of aging, measure the open circuit voltage (OCV) of the battery. Measure the OCV of the battery, for example, by placing a voltmeter on the positive and negative terminals of the battery. Report the measured open circuit voltage (V) of the battery. The OCV test does not consume the capacity of the battery.

[0093] After 4 days of aging, the short - circuit current (SCC) of the battery is measured. The protocol for the SCC test includes passing a constant current of 6 amperes (A) for 0.1 seconds from the battery. The voltage of the battery is measured and reported under a 6 A drain. If the battery is fully short - circuited, the measured voltage of the battery should be zero (0) volts. The current at which the battery should be short - circuited is calculated by extrapolating the line connecting the coordinates of the measured OCV and the measured voltage under the drain to the x - axis intercept on an x,y plot of current vs. voltage. The measured OCV has the (x,y) coordinates of (0 A, measured OCV). The measured voltage under the drain has the (x,y) coordinates of (6 A, measured load voltage). The SSC test does not consume a large portion of the total capacity of the battery because the duration of the test is very short. Calculate the SSC as follows. SSC(A)=[(OCV·6A) / (OCV - load voltage)]

[0094] The performance test includes a discharge performance test that can be called a 30 milliampere (30 mA) continuous discharge test. The protocol for the 30 mA continuous discharge test includes discharging the battery at a constant current drain of 30 mA until a cut - off voltage of 0.9 volts is reached. The measured capacity of the battery discharged to the cut - off voltage is called the total capacity of the battery. The total capacity of the battery is usually reported in both ampere - hours (Ah) and watt - hours (Wh). Consider the 30 mA continuous discharge test as a low - drain continuous discharge test of a conventional alkaline AA battery.

[0095] The performance test includes a discharge performance test in a high - speed continuous discharge regime called a 1 watt (1 W) continuous discharge test. The protocol for the 1 W continuous discharge test includes discharging the battery at a constant current drain of 1 watt until a cut - off voltage of 0.9 volts is reached. The measured capacity of the battery discharged to the cut - off voltage is usually reported in both ampere - hours (Ah) and watt - hours (Wh). Consider the 1 W continuous discharge test as a high - drain discharge test of a conventional alkaline AA battery.

[0096] The performance test includes a discharge performance test in a medium-speed intermittent discharge regime called the 250 milliwatt (250 mW) intermittent discharge test. The protocol for the 250 mW intermittent discharge test includes discharging the battery at a constant current drain of 250 mW for 1 hour. The discharge is then stopped and the battery is rested for 7 hours. Further cycles of discharge and rest are then applied to the battery until a cut-off voltage of 0.9 volts is reached. The measured capacity of the battery is usually reported in both ampere-hours (Ah) and watt-hours (Wh). The 250 mW intermittent discharge test is considered a medium-drain discharge test of a conventional alkaline AA battery.

[0097] The performance test includes a discharge performance test designed to simulate use in a digital camera, which may be called the Digital Camera (Digicam) test. The Digicam test is a pulse test protocol that includes discharging the battery with high and medium output pulse discharge cycles. Each discharge cycle consists of a combination of two discharge regimes including a 1.5 watt high output pulse for 2 seconds and a 650 mW medium output pulse for 28 seconds immediately following. This combination of discharge regimes is repeated 10 times (i.e., for a total of 5 minutes), and then the battery is rested for 55 minutes. The combination of high and medium output discharge pulses and rest periods (i.e., 1 hour / cycle) is repeated until a cut-off voltage of 1.05 volts is reached. The number of cycles required to reach the cut-off voltage is reported as the "pulses" or "images". The number of pulses reported consists of the total number of 1.5 watt high output pulses corresponding to the total number of discharge cycles. The Digicam discharge test is considered a high-speed intermittent discharge test of a conventional AA battery.

[0098] Performance test results Performance tests were conducted on both Battery A and Battery B for OCV, SSC, 30 mA continuous, 1 W continuous, 250 mW intermittent, and Digicam. The performance test results are summarized in Table 5 below. The % difference column in Table 5 includes the percentage difference in the performance of Battery B relative to Battery A. Battery B, which includes a non-stoichiometric beta delithiated layered nickel oxide as an electrochemically active cathode material, provides an overall performance improvement when compared to Battery A, i.e., a typical commercially available conventional alkaline single 3 - cell battery. The OCV of Battery B is higher than that of Battery A. The higher OCV of Battery B indicates a higher total energy compared to Battery A. Since the OCV of Battery B is not extremely high, the potential for damage when Battery B is incorporated into an electrical device is relatively low. The SSC of Battery B is significantly higher than that of Battery A. The higher SSC of Battery B indicates a higher ability to supply a higher discharge current than Battery A. Except for the 1 W continuous test, the current amount in Ah units supplied by Battery B under all discharge tests is larger than that of Battery A. The energy amount in Wh units supplied by Battery B under all discharge tests is larger than that of Battery A. In addition, the number of pulses supplied by Battery B under the Digicam test is also much larger than that of Battery A. The results indicate that Battery B generally has better performance than Battery A for low - speed, medium - speed, and high - speed discharge test regimes.

Table 5

[0099] The dimensions and values disclosed in this specification are not to be understood as being strictly limited to the exact numerical values recited. Rather, unless otherwise specified, each such dimension is intended to mean both the recited value and the functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0100] All documents cited herein, including any patents or applications that are cross-referenced or related, and any patent application or patent for which this application claims priority or benefit, are hereby incorporated by reference in their entirety, except as explicitly excluded or otherwise limited. The citation of a document does not admit that it is prior art with respect to the invention disclosed or claimed herein, nor that it teaches, suggests or discloses such an invention, alone or in combination with any other one or more reference documents. Further, the meaning or definition of a term in this specification applies to that term as used in this specification, unless the meaning or definition of the same term in a document incorporated by reference conflicts with the meaning or definition given to that term in this specification.

[0101] While particular embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the scope of the invention be covered by the appended claims and all such changes and modifications that fall within the scope of the claims.

Claims

1. A method for preparing a non-stoichiometric, beta-delithiated layered nickel oxide cathode material, comprising the steps of: using an oxidizing agent selected from the group consisting of sodium peroxydisulfate, potassium peroxydisulfate, ammonium peroxydisulfate, sodium hypochlorite, sodium permanganate, potassium permanganate, sodium dichromate, potassium dichromate, and combinations thereof, a compound of the general formula Li 1-a Ni 1+a-z M z O 2 wherein 0.02≦a<0.2 and 0≦z<0.2, and wherein the non-stoichiometric lithium nickelate has the general formula Li x H w Ni 1+a-z M z O 2 wherein 0.02≦x≦0.2, 0≦w≦0.2, and 0.02≦a≦0.2, 0≦z<0.2; and preparing a non-stoichiometric beta-delithiated layered nickel oxide from the non-stoichiometric alpha-delithiated layered nickel oxide comprising the general formula Li x H w Ni 1+az M z O 2 .

2. The non-stoichiometric lithium nickelate has the formula Li x H w Ni 1+a O 2 2. The method of claim 1 , wherein z is 0, so as to constitute:

3. 3. The method of claim 1 or claim 2, wherein the oxidizing agent is selected from the group of sodium peroxydisulfate, potassium peroxydisulfate, ammonium peroxydisulfate, and combinations thereof.

4. 3. The method of claim 1 or 2, wherein a is from 0.03 to 0.

15.

5. 3. The method of claim 1 or 2, wherein x is from 0.05 to 0.

12.

6. 3. The method of claim 1 or claim 2, further comprising treating the non-stoichiometric, alpha-delithiated layered nickel oxide with an aqueous hydroxide solution.

7. 7. The method of claim 6, wherein the aqueous hydroxide solution comprises potassium hydroxide, cesium hydroxide, rubidium hydroxide, or a combination thereof.

8. 7. The method of claim 6, wherein the concentration of the aqueous hydroxide solution is from about 0.5M to about 10M.

9. 1. A method for producing an alkaline primary battery, comprising: preparing a cathode active material by a process comprising oxidizing a nonstoichiometric lithium nickelate having a general formula Li1-aNi1+azMzO2 with an oxidizing agent comprising a peroxydisulfate, a monopersulfate, or a combination thereof, wherein 0.02≦a<0.2 and 0≦z<0.2, and wherein the general formula Li x H w Ni 1+a-z M z O 2 wherein 0.02≦x≦0.2, 0≦w≦0.2, and 0.02≦a≦0.2, 0≦z<0.2; and preparing a non-stoichiometric beta-delithiated layered nickel oxide electrochemically active cathode material from the non-stoichiometric alpha-delithiated layered nickel oxide comprising the general formula Li x H w Ni 1+az M z O 2 ; incorporating the cathode material into a cathode; incorporating the cathode into the battery; incorporating an anode into said battery; incorporating an aqueous alkaline electrolyte into said battery.

10. The non-stoichiometric lithium nickelate has the formula Li x H w Ni 1+a O 2 10. The method of claim 9, wherein z is 0, so as to constitute:

11. 11. The method of claim 9 or claim 10, wherein the oxidizing agent is selected from the group of sodium peroxydisulfate, potassium peroxydisulfate, ammonium peroxydisulfate, and combinations thereof.

12. 11. The method of claim 9 or claim 10, wherein a is from 0.03 to 0.

15.

13. 11. The method of claim 9 or 10, wherein x is from 0.05 to 0.

12.

14. 11. The method of claim 9 or claim 10, further comprising treating the non-stoichiometric, alpha-delithiated layered nickel oxide with an aqueous hydroxide solution.

15. 15. The method of claim 14, wherein the aqueous hydroxide solution comprises potassium hydroxide, cesium hydroxide, rubidium hydroxide, or a combination thereof.

16. 15. The method of claim 14, wherein the concentration of the aqueous hydroxide solution is from about 0.5M to about 10M.

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