Sodium nickelate cathode material synthesis using persulfate desodiumation and oxidation, and uses thereof

Abstract

Methods for preparing desodium and oxide sodium nickelate materials using persulfate solutions and sodium nickelate materials prepared by such methods are disclosed. Methods for preparing pre-aged beta nickelates using hydroxide solutions and beta nickelates prepared by such methods are also disclosed. Alkaline cathode compositions are provided that include electrolytic manganese dioxide, desodium and oxide sodium nickelates and beta nickelates, and alkaline electrochemical cells are provided that include these nickelates and compositions.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 363,059, filed April 15, 2022, which is incorporated by reference herein in its entirety for all of its teachings. [Background technology]

[0002] Alkaline electrochemical cells are commercially available in cell sizes commonly known as LR6 (AA), LR03 (AAA), LR14 (C), and LR20 (D). These cells have a cylindrical shape that conforms to dimensional standards set by organizations such as the International Electrotechnical Commission. Electrochemical cells are utilized by consumers to power a wide range of electrical devices, such as clocks, radios, toys, electronic games, film cameras that typically include flash bulb units, and digital cameras. Such electrical devices have a wide range of discharge conditions, such as low drain to relatively high drain.

[0003] Since batteries are often of a fixed shape and size, battery manufacturers must modify the characteristics of the cells to increase performance. Attempts to address the problem of how to improve the performance of a battery in a particular device, such as a digital camera, typically involve changes to the internal structure of the cell. For example, the cell structure has been modified by increasing the amount of active material utilized within the cell.

[0004] High valent nickel materials, including nickel oxyhydroxide (NiOOH), nickel dioxide (NiO2), and various forms of nickel oxide, nickelates, and nickel oxyhydroxide, are useful as cathode materials in alkaline systems due to their high capacity and cell voltage. In particular, delithiated LiNiO2, e.g., Li xNiO2 (where x<<1) has an oxidation state higher than 3+, which potentially results in a much higher discharge capacity than EMD (MnO2). However, nickelate Li x NiO2 is intrinsically unstable and degrades rapidly at high temperatures. Furthermore, these materials are thermodynamically unstable in aqueous electrolytes, which leads to electrochemical reduction of the nickel cathode (loss of electrode capacity). Thus, the shelf life of alkaline cells with high valence nickel cathodes is limited compared to cells containing certain other cathode materials. Summary of the Invention

[0005] One embodiment of the present invention is a nickelate material having an X-ray diffraction (XRD) pattern that includes a first peak between about 12° and 14° 2θ, a second peak between about 18° and 21° 2θ, a third peak between about 24° and 25° 2θ, and a fourth peak set between about 36° and 43° 2θ. In alternative embodiments, the desodium nickelate material has an XRD pattern that includes at least one, two, three, or four of these four peaks or sets of peaks.

[0006] One embodiment is a method for preparing a persulfate-treated desodium and oxidized nickelate, the method comprising contacting sodium nickelate with a persulfate solution to produce a persulfate-treated desodium and oxidized nickelate.

[0007] One embodiment is a nickelate material prepared by any of the methods described herein.

[0008] One embodiment is an alkaline cathode composition comprising any of the nickelate materials described herein and electrolytic manganese dioxide (EMD).

[0009] One embodiment is an alkaline cathode composition comprising any of the sodiated and oxidized nickelate materials described herein, electrolytic manganese dioxide, graphite, and a binder.

[0010] One embodiment is a pre-aged beta nickelate material having an X-ray diffraction (XRD) pattern including a first peak between about 50.0° and 52.0° 2θ, a second peak between about 53.6° and 56.8° 2θ, a third peak between about 60.8° and 62.6° 2θ, a fourth peak between about 66.4° and 67.5° 2θ, and a fifth peak between about 67.4° and 68.6° 2θ. In an alternative embodiment, the desodium nickelate material has an XRD pattern with at least 1, 2, 3, 4, or 5 of these five peaks.

[0011] One embodiment is a method of preparing a pre-aged beta-nickelate material, the method comprising contacting a beta-nickelate with a pre-aging solution comprising a hydroxide to produce the pre-aged nickelate material.

[0012] One embodiment is a beta-nickelate material made by any of the methods described herein.

[0013] One embodiment is an alkaline cathode composition comprising any of the beta-nickelate materials described herein and electrolytic manganese dioxide (EMD).

[0014] One embodiment is a composition comprising any of the beta-nickelate materials described herein, electrolytic manganese dioxide, graphite, and a binder.

[0015] One embodiment is an alkaline electrochemical cell comprising any of the nickelate materials or compositions described herein. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional elevation view of an alkaline electrochemical cell of one embodiment. [Diagram 2]Yields and chemical reactions for acid desodiumation / disproportionation and persulfate desodiumation / oxidation are shown. [Diagram 3] 1 shows an X-ray diffraction (XRD) pattern for sodium nickel oxide. [Figure 4] 1 shows an X-ray diffraction (XRD) pattern for desodium sodium nickel oxide. [Diagram 5] 1 shows the X-ray diffraction (XRD) patterns for desodium nickel oxide and sodium oxide desodium with persulfate. [Figure 6] The discharge capacity (10 mA / g) of the dried powder before and after aging at 70° C. / 50% RH for 4 weeks is shown. [Figure 7] 1 shows the X-ray diffraction (XRD) pattern for beta-nickelate pre-aged with LiOH. [Figure 8] 1 shows the discharge curves of a beta-nickelate with O / C=1 before and after pre-aging with LiOH. [Figure 9] 1 shows the discharge curves of beta nickelate with O / C=14.5 mixed with EMD before and after pre-aging with LiOH. [Figure 10] 1 shows a discharge energy comparison between beta nickelate and sodium persulfate desodium and sodium oxide nickel oxide after aging at 60° C. [Figure 11] 4 shows the discharge curves of mixtures of EMD with various levels of persulfate desodium and sodium oxide nickel oxide. [Figure 12] The discharge efficiency and energy versus the weight percent Ni in the EMD / nickelate mixture are shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Various embodiments will now be described more fully below with reference to the accompanying drawings, in which some, but not all, embodiments are illustrated. Indeed, various embodiments may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numerals refer to like elements throughout. In the following description, various components may be identified as having specific values ​​or parameters, but these are provided as exemplary embodiments. Indeed, the exemplary embodiments are not intended to limit various aspects and concepts of the embodiments, since many equivalent parameters, sizes, ranges, and / or values ​​may be implemented. Terms such as "primary," "exemplary," and "secondary," such as "first" and "second," do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Furthermore, the terms "a," "an," and "the" do not denote a limitation of quantity, but rather indicate the presence of "at least one" of the referenced item.

[0018] This embodiment was designed to overcome the limitations of existing electrochemical cells. Typically, NaNiO2 is derived from acid leached NaNiO2. x NiO2 is an oxide delithiation Li x An oxidation / desodium process is disclosed that results in a sodium nickelate material having improved chemical stability at high temperatures and a higher nickelate material yield from the oxidation / desodium process than the commonly used acid leaching process.

[0019] Each embodiment disclosed herein is contemplated to be applicable to each of the other disclosed embodiments. All combinations and subcombinations of the various elements described herein are within the scope of the embodiments.

[0020] Where a parameter range is provided, it is understood that all integers and ranges within that range, as well as tenths and hundredths thereof, are also provided by the embodiment. For example, "5-10%" includes 5%, 6%, 7%, 8%, 9%, and 10%, 5.0%, 5.1%, 5.2%, ....9.8%, 9.9%, and 10.0%, as well as 5.00%, 5.01%, 5.02%, ....9.98%, 9.99%, and 10.00%, as well as, for example, 6-9%, 5.1%-9.9%, and 5.01%-9.99%.

[0021] As used herein, "about" in the context of a numerical value or range means within ±10%, ±5%, or ±1% of the recited or claimed numerical value or range.

[0022] As used herein, "nickelate" refers to a salt containing an anion containing nickel or a compound that contains nickel bound to oxygen and at least one other element.

[0023] As used herein, "nickel compound" refers to any compound that contains nickel.

[0024] As used herein, "nickel precursor" refers to a compound that contains nickel and that reacts with a sodium-containing compound to produce a different compound that contains nickel.

[0025] As used herein, "oxide" refers to a chemical compound that contains at least one oxygen atom and one other element. As used herein, "nickel oxide" refers to any nickel-containing oxide. Nickel oxides may contain other cations and anions. Non-limiting examples include nickel dioxide (NiO2), nickel hydroxide (Ni(OH)2), and hydrated alkali nickel oxides, e.g., Na x Examples include NiO2·n(H2O).

[0026] As used herein, "oxyhydroxide" refers to a chemical compound or complex that contains oxide and hydroxide groups. As used herein, "nickel oxyhydroxide" refers to any nickel-containing oxyhydroxide. Nickel oxyhydroxides may contain other cations and anions. A non-limiting example is nickel oxyhydroxide (NiOOH).

[0027] As used herein, "persulfate" refers to the persulfate anion (SO5 2- or S2O8 2- ) Non-limiting examples include sodium persulfate (NaS2O8), ammonium persulfate (NH4)2S2O8, and potassium persulfate (K2S2O8).

[0028] As used herein, "sodium compound" refers to any compound that contains sodium. In one embodiment, the sodium compound contains both sodium and oxygen. Non-limiting examples include NaOH (sodium hydroxide), Na2O (sodium oxide), NaO2 (sodium peroxide), and Na x NiO2 (sodium nickel oxide) is one example.

[0029] As used herein, "improvement" with respect to storage stability means that the storage stability (i.e., "shelf life") is increased. In general, an "improvement" in a property or metric of performance of a material or electrochemical cell means that the property or metric of performance is different (compared to the property or metric of a different material or electrochemical cell) in a way that a user or manufacturer of the material or cell considers desirable (i.e., lower cost, lasts longer, provides more power, is more durable, is easier or faster to manufacture, etc.).

[0030] As used herein, an "alkali metal" is an element from Group IA of the periodic table. Non-limiting examples include Li, Na, K, Rb, and Cs.

[0031] As used herein, an "alkaline earth metal" is an element from Group IIA of the periodic table. Non-limiting examples include Mg, Ca, and Sr.

[0032] As used herein, a "transition metal" is an element from groups IB-VIIIB of the periodic table. Non-limiting examples include Co, Mn, Zn, Y, Nb, and Ti.

[0033] As used herein, "other metals" or "another metal" includes all metals on the periodic table not included within the groups above, including Al, Ga, In, Sn, Tl, Pb, and Bi.

[0034] As used herein, a "primary" electrochemical cell is a non-rechargeable (i.e., disposable) electrochemical cell. A "secondary" electrochemical cell is a rechargeable electrochemical cell.

[0035] As used herein, "electrical conductivity" refers to the ability of a given material to conduct electric current, typically measured in Siemens per meter (S / m).

[0036] As used herein, the term "pre-aging" or "pre-aged" refers to a controlled process for converting a material such that the resulting phase or mixture of different phases is more stable over time when utilized in an end product. For example, a cathode material may be pre-aged using the processes discussed herein to provide a more storage stable cathode material when included in a battery. In certain embodiments, nickel oxides are pre-aged by exposing the material to specific concentrations of LiOH, NaOH, KOH, and / or other oxides or hydroxides at specific temperatures and for specified periods of time. Another hypothesis is that pre-aging may also form a protective film on the surface of the higher nickel oxidation state of the nickel particles to retard the decomposition reaction from the higher nickel oxidation state to the lower nickel oxidation state.

[0037] One embodiment is a nickelate material having an X-ray diffraction (XRD) pattern including a set of a first peak at about 12° - 14° 2θ, a second peak at about 18° - 21° 2θ, a third peak at about 24° - 25° 2θ, and a fourth peak at about 36° - 43° 2θ. In an alternative embodiment, the de-sodiumated nickelate material has an XRD pattern having at least 1, 2, 3, or 4 of these four peaks or sets of peaks.

[0038] In one embodiment, the nickelate material is a de-sodiumated and sodium-oxidized nickelate material.

[0039] In one embodiment, the de-sodiumated and oxidized nickelate material is a de-sodiumated nickelate hydride, and the de-sodiumated nickelate hydride has the following phases: i) Sodium nickel oxide having the formula (Na x NiO2·nH2O) in an amount of 40 - 90 wt%, where 0.2 ≦ x < 1 and 0 < n < 2, ii) Nickel oxide (NiO2) in an amount of 5 - 40 wt%, and iii) Beta-nickel hydroxide (NiOOH) in an amount of 5 - 20 wt%.

[0040] One embodiment is a method for preparing a persulfate-treated de-sodiumated and oxidized nickelate, the method including contacting sodium nickelate with a persulfate solution to produce a persulfate-treated de-sodiumated and oxidized nickelate.

[0041] In one embodiment, the persulfate de-sodiumated and oxidized nickelate is a mixture of nickel oxide, sodium nickel oxide hydrate, and / or nickel oxide hydroxide.

[0042] In one embodiment, the persulfate-treated de-sodiumated and oxidized nickelate has the following phases: i) Sodium nickel oxide having the formula (Na x NiO2·nH2O) in an amount of 40 to 90% by weight, wherein 0.2 ≦ x < 1 and 0 < n < 2, ii) nickel dioxide (NiO2) in an amount of 5 to 40% by weight, and iii) beta-nickel hydroxide (NiOOH) in an amount of 5 to 20% by weight.

[0043] This is a mixed-phase nickelate. In one embodiment, x is within a range defined by at least, at most, or about 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, or any range defined by any two of these values. In one embodiment, n is within a range defined by at least, at most, or about 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2, or any range defined by any two of these values. In one embodiment, the molar ratio of persulfate to nickel is about 2 to 4. In one embodiment, the molar ratio is within a range defined by at least, at most, or about 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4, or any range defined by any two of these values.

[0044] In one embodiment, the sodium nickelate is contacted with a persulfate solution for a period of about 1 to 72 hours. In one embodiment, the period is within a range defined by at least, at most, or about 1, 2, 4, 8, 12, 16, 20, 24, 30, 36, 42, 48, 54, 60, 66, or 72 hours, or any range defined by any two of these values.

[0045] In one implementation, the method is performed at a temperature less than or equal to 50° C. In one implementation, the temperature is at least, up to, or about 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50° C., or within a range defined by any two of these values.

[0046] In one embodiment, the pH of the persulfate solution is about 12 to 14. In one embodiment, the pH of the persulfate solution is at least, up to, or about 12, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, or 14, or within a range defined by any two of these values.

[0047] In one embodiment, the persulfate solution comprises a persulfate selected from the group consisting of potassium persulfate and sodium persulfate. In one embodiment, the persulfate is potassium persulfate. In one embodiment, the persulfate is sodium persulfate.

[0048] One embodiment is a nickelate material prepared by any of the methods described herein.

[0049] One embodiment is an alkaline cathode composition comprising any of the nickelate materials described herein and electrolytic manganese dioxide (EMD).

[0050] In one embodiment, the weight ratio of nickel to manganese is from about 99:1 to 1:99. In one embodiment, the ratio of nickel to manganese is at least, up to, or about 99:1, 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, 5:95, or 1:99, or within a range defined by any two of these values.

[0051] One embodiment is an alkaline cathode composition comprising any of the sodiated and oxidized nickelate materials described herein, electrolytic manganese dioxide, graphite, and a binder.

[0052] In one embodiment, the desodium and oxidized nickelate material is present in an amount of about 8.8-45.1 wt%, the electrolytic manganese dioxide (EMD) is present in an amount of about 48-84.3 wt%, the graphite is present in an amount of about 3-8 wt%, and the binder is present in an amount of about 0.1-1.0 wt%, based on the total weight of the nickelate, EMD, graphite, and binder. In one embodiment, the nickelate is present in an amount of at least, up to, or about 8.8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, or 45.1 wt.%, or within a range defined by any two of these values.

[0053] In one embodiment, EMD is present in an amount of at least, up to, or about 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, or 84.3 weight percent, or within a range defined by any two of these values. In one embodiment, graphite is present in an amount of at least, up to, or about 3, 4, 5, 6, 7, or 8 weight percent, or within a range defined by any two of these values. In one embodiment, the binder is present in an amount of at least, up to, or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 wt. %, or within a range defined by any two of these values.

[0054] In one embodiment, the desodiated and oxidized nickelate materials and EMD together are present in an amount of about 92-97 wt%, the graphite is present in an amount of about 3-8 wt%, and the binder is present in an amount of about 0.1-1.0 wt%. In one embodiment, the desodiated and oxidized nickelate materials and EMD together are present in an amount of at least, up to, or about 92, 93, 94, 95, 96, or 97 wt%, or within a range defined by any two of these values. In one embodiment, the graphite is present in an amount of at least, up to, or about 3, 4, 5, 6, 7, or 8 wt%, or within a range defined by any two of these values. In one embodiment, the binder is present in an amount of at least, up to, or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 wt%, or within a range defined by any two of these values.

[0055] One embodiment is a pre-aged beta nickelate material having an X-ray diffraction (XRD) pattern including a first peak between about 50.0° and 52.0° 2θ, a second peak between about 53.6° and 56.8° 2θ, a third peak between about 60.8° and 62.6° 2θ, a fourth peak between about 66.4° and 67.5° 2θ, and a fifth peak between about 67.4° and 68.6° 2θ. In an alternative embodiment, the desodium nickelate material has an XRD pattern with at least 1, 2, 3, 4, or 5 of these five peaks.

[0056] In one embodiment, the pre-aged beta-nickelate material is prepared by pre-aging beta-nickelate with a pre-aging solution that includes a hydroxide.

[0057] In one embodiment, the hydroxide is selected from the group consisting of alkali and alkaline earth metal hydroxides. In one embodiment, the hydroxide is selected from the group consisting of LiOH, NaOH, KOH, and Ca(OH). In one embodiment, the hydroxide is LiOH, NaOH, or KOH. In one embodiment, the hydroxide is LiOH. In one embodiment, the hydroxide is NaOH. In one embodiment, the hydroxide is KOH.

[0058] In one embodiment, the hydroxide concentration of the pre-aging solution is from about 0.005 M to about 1 M. In one embodiment, the hydroxide concentration is at least, up to, or about 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 M, or within a range defined by any two of these values.

[0059] In one embodiment, the ratio of pre-aging solution to beta-nickelate was from about 1 mL / g to about 200 mL / g, hi one embodiment, the ratio was at least, up to, or about 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 mL / g, or within a range defined by any two of these values.

[0060] In one embodiment, the beta nickelate is pre-aged for about 1-60 minutes. In one embodiment, the beta nickelate precursor is pre-aged for about 1-30 minutes, or for about 1-20 minutes. In one embodiment, the beta nickelate is pre-aged for at least, up to, or about 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes, or within a range defined by any two of these values.

[0061] In one embodiment, the beta nickelate is pre-aged at a temperature between about 0° C. and about 40° C. In one embodiment, the beta nickelate is pre-aged at a temperature at least, up to, or within a range defined by any two of these values.

[0062] In one embodiment, the pre-aged beta nickelate comprises beta nickelate, nickel oxide, beta nickel oxyhydroxide, or a combination thereof.

[0063] One embodiment is a method of preparing a pre-aged beta-nickelate material, the method comprising contacting a beta-nickelate with a pre-aging solution comprising a hydroxide to produce the pre-aged nickelate material.

[0064] In one embodiment, the hydroxide is selected from the group consisting of alkali and alkaline earth metal hydroxides. In one embodiment, the hydroxide is selected from the group consisting of LiOH, NaOH, KOH, and Ca(OH). In one embodiment, the hydroxide is LiOH, NaOH, or KOH. In one embodiment, the hydroxide is LiOH. In one embodiment, the hydroxide is NaOH. In one embodiment, the hydroxide is KOH.

[0065] In one embodiment, the hydroxide concentration of the pre-aging solution is from about 0.005 M to about 1 M. In one embodiment, the hydroxide concentration is at least, up to, or about 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 M, or within a range defined by any two of these values.

[0066] In one embodiment, the ratio of pre-aging solution to beta-nickelate was from about 1 mL / g to about 200 mL / g, hi one embodiment, the ratio was at least, up to, or about 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 mL / g, or within a range defined by any two of these values.

[0067] In one embodiment, the beta nickelate is pre-aged for about 1-60 minutes. In one embodiment, the beta nickelate precursor is pre-aged for about 1-30 minutes, or for about 1-20 minutes. In one embodiment, the beta nickelate is pre-aged for at least, up to, or about 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes, or within a range defined by any two of these values.

[0068] In one embodiment, the temperature is from about 0° C. to about 40° C. In one embodiment, the temperature is at least, up to, or about 0, 5, 10, 15, 20, 25, 30, 35, or 40° C., or within a range defined by any two of these values.

[0069] One embodiment is a beta-nickelate material made by any of the methods described herein.

[0070] One embodiment is an alkaline cathode composition comprising any of the beta-nickelate materials described herein and electrolytic manganese dioxide (EMD).

[0071] In one embodiment, the weight ratio of nickel to manganese is from about 99:1 to 1:99. In one embodiment, the ratio of nickel to manganese is at least, up to, or about 99:1, 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, 5:95, or 1:99, or within a range defined by any two of these values.

[0072] One embodiment is a composition comprising any of the beta-nickelate materials described herein, electrolytic manganese dioxide, graphite, and a binder.

[0073] In one embodiment, the nickel from the beta-nickelate material is present in an amount of about 8.8-45.1 wt.%, the electrolytic manganese dioxide is present in an amount of about 48-84.3 wt.%, the graphite is present in an amount of about 3-8 wt.%, and the binder is present in an amount of about 0.1-1.0 wt.%, based on the total weight of the nickelate, EMD, graphite, and binder. In one embodiment, nickel is present in an amount of at least, up to, or about 8.8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, or 45.1 wt.%, or within a range defined by any two of these values.

[0074] In one embodiment, EMD is present in an amount of at least, up to, or about 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, or 84.3 weight percent, or within a range defined by any two of these values. In one embodiment, graphite is present in an amount of at least, up to, or about 3, 4, 5, 6, 7, or 8 weight percent, or within a range defined by any two of these values. In one embodiment, the binder is present in an amount of at least, up to, or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 wt. %, or within a range defined by any two of these values.

[0075] In one embodiment, the beta nickelate material and EMD together are present in an amount of about 92-97 wt%, the graphite is present in an amount of about 3-8 wt%, and the binder is present in an amount of about 0.1-1.0 wt%. In one embodiment, the desodium and oxidized nickelate material and EMD together are present in an amount of at least, up to, or about 92, 93, 94, 95, 96, or 97 wt%, or within a range defined by any two of these values. In one embodiment, the graphite is present in an amount of at least, up to, or about 3, 4, 5, 6, 7, or 8 wt%, or within a range defined by any two of these values. In one embodiment, the binder is present in an amount of at least, up to, or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 wt%, or within a range defined by any two of these values.

[0076] In one embodiment, any of the nickelate materials described herein is a nickelate cathode material.

[0077] One embodiment is an alkaline electrochemical cell comprising any of the nickelate materials or compositions described herein.

[0078] The embodiments may be better understood by reference to FIG. 1. FIG. 1 shows a cylindrical cell 1 with a raised cross section, the cell having a peg- or bobbin-type construction and dimensions comparable to conventional LR6 (AA) size alkaline cells that are particularly suitable for the embodiments. However, it should be understood that cells according to the embodiments may have other sizes and shapes, e.g., prismatic or button-shaped shapes, as well as other electrode configurations, as known in the art. The materials and designs for the components of the electrochemical cell shown in FIG. 1 are for illustrative purposes, and other materials and designs may be substituted. Furthermore, in certain embodiments, the cathode and anode materials may be coated onto the surface of the separator and / or current collector and rolled to form a "jelly roll" configuration.

[0079] In FIG. 1, an electrochemical cell 1 is shown including a container or can 10 having a closed bottom end 24, a top end 22, and a sidewall 26 between the electrochemical cell 1. The closed bottom end 24 includes a terminal cover 20 including a protrusion. The can 10 has an interior wall 16. In an embodiment, the positive terminal cover 20 is welded or otherwise attached to the bottom end 24. In one embodiment, the terminal cover 20 may be formed of plated steel, for example, having a protruding protrusion in its central region. The container 10 may be formed of a metal, such as steel, preferably plated with nickel, cobalt, and / or other metals or alloys, or other materials on its interior, and has sufficient structural properties to be compatible with the various inputs in the electrochemical cell. A label 28 may be formed around the exterior of the container 10 and on the periphery of the positive terminal cover 20 and the negative terminal cover 46, so long as the negative terminal cover 46 is electrically insulated from the container 10 and the positive terminal 20.

[0080] Disposed within the container 10 are a first electrode 18 and a second electrode 12 with a separator 14 disposed therebetween. The first electrode 18 is disposed within a space defined by the separator 14 and a closure assembly 40 secured to an open end 22 of the container 10. The closed end 24, sidewall 26, and closure assembly 40 define a cavity in which the cell's electrodes are housed.

[0081] The closure assembly 40 includes a closure member 42, such as a gasket, a current collector 44, and a conductive terminal 46 in electrical contact with the current collector 44. The closure member 42 preferably includes a pressure relief vent that allows the closure member to rupture if the internal pressure of the cell becomes excessive. The closure member 42 may be formed from a polymeric or elastomeric material, such as nylon 6,6, an injection moldable polymer blend, such as a combination of a polypropylene matrix with poly(phenylene oxide) or polystyrene, or another material, such as a metal, provided that the current collector 44 and the conductive terminal 46 are electrically insulated from the container 10, which serves as a current collector for the second electrode 12. In the illustrated embodiment, the current collector 44 is an elongated nail-like or bobbin-shaped component. The current collector 44 is made of a metal or metal alloy, such as copper or brass, a conductively plated metal or plastic current collector, or the like. Other suitable materials may be utilized. The current collector 44 is inserted through a preferably centrally located hole in the closure member 42 .

[0082] The first electrode 18 is preferably the negative electrode or anode. The negative electrode includes a mixture of one or more active materials, a conductive material, solid zinc oxide, and a surfactant. The negative electrode may optionally include other additives, such as a binder or gelling agent.

[0083] Zinc is an exemplary primary active material for the negative electrode of embodiments. Mercury and magnesium may also be used. Preferably, the volume of active material utilized in the negative electrode is sufficient to maintain the desired interparticle contact and the desired anode to cathode (A:C) ratio.

[0084] Interparticle contact should be maintained throughout the life of the battery. If the volume of active material in the negative electrode is too low, the cell voltage may suddenly drop to an unacceptably low value while the cell is powering a device. The voltage drop is believed to be caused by a loss of continuity in the conductive matrix of the negative electrode. The conductive matrix can be formed from undischarged active material particles, conductive electrochemically formed oxides, or a combination thereof. The voltage drop can occur even after oxides begin to form, but before a sufficient network is built to bridge between all the active material particles present.

[0085] The aqueous alkaline electrolyte may include an alkali metal hydroxide, such as potassium hydroxide (KOH) or sodium hydroxide (NaOH), or mixtures thereof. Potassium hydroxide is preferred. The alkaline electrolyte used to form the gel electrolyte of the negative electrode contains an alkali metal hydroxide in an amount of about 26 to about 36 weight percent, such as about 26 to about 32 weight percent, specifically about 26 to about 30 weight percent, based on the total weight of the alkaline electrolyte. It has been found that an interaction occurs between the negative electrode alkali metal hydroxide and the added solid zinc oxide, and lower alkali metal hydroxide improves DSC service. A less alkaline electrolyte is preferred, but may result in rapid electrolyte separation of the anode. An increase in alkali metal hydroxide concentration results in a more stable anode, but may reduce DSC service.

[0086] A gelling agent is preferably utilized in the negative electrode as is well known in the art, such as cross-linked polyacrylic acid, such as Carbopol® 940, available from Noveon, Inc. of Cleveland, Ohio, USA. Carboxymethylcellulose, polyacrylamide, and sodium polyacrylate are examples of other gelling agents suitable for use in alkaline electrolyte solutions. A gelling agent is desirable to maintain a substantially uniform dispersion of zinc and solid zinc oxide particles within the negative electrode. The amount of gelling agent present is selected to provide a lower electrolyte separation rate and to avoid too high anode viscosity at yield stress, which can cause problems with anode dispensing.

[0087] Other components that may optionally be present in the anode include, but are not limited to, gassing inhibitors, organic or inorganic corrosion inhibitors, plating agents, binders, or other surfactants. Examples of gassing inhibitors or corrosion inhibitors may include indium salts, such as indium hydroxide, perfluoroalkyl ammonium salts, alkali metal sulfides, and the like. In one embodiment, dissolved zinc oxide is present, preferably via dissolution in the electrolyte, to improve plating on the bobbin or nail current collector and reduce anode storage gassing. The dissolved zinc oxide added is separate and distinct from the solid zinc oxide present in the anode composition. In one embodiment, a level of dissolved zinc oxide in an amount of about 1 weight percent based on the total weight of the anode electrolyte is preferred. Soluble or dissolved zinc oxide generally has a surface area of ​​about 4 m2 as measured utilizing a Tristar 3000 BET specific surface area analyzer with multipoint calibration from Micrometrics after the zinc oxide is degassed at 150° C. for 1 hour. 2 / g or less and has a particle size D50 (median diameter) of about 1 micron as measured using a CILAS particle size analyzer as described above. In a further embodiment, sodium silicate in an amount of about 0.3 weight percent based on the total weight of the negative electrode electrolyte is preferred in the negative electrode to substantially prevent cell shorting through the separator during cell discharge.

[0088] The negative electrode can be formed in a number of different ways, as is known in the art, for example, the negative electrode components can be dry blended and added to the cell, the alkaline electrolyte is added separately, or, as in the preferred embodiment, a pre-gelled negative electrode process is utilized.

[0089] The second electrode 12, also referred to herein as the positive electrode or cathode, has a nickelate compound (or "nickelate cathode material") as its electrochemically active material. The active material is generally present in an amount of about 80 to about 98 weight percent, preferably about 81 to 97 weight percent, based on the total weight of the positive electrode, i.e., the nickelate cathode material, binder, conductive material, positive electrolyte, and additives, if present.

[0090] The active cathode material may be a blend of nickelate cathode material with other active materials such as electrolytic manganese dioxide (EMD), chemical manganese dioxide (CMD), and copper oxide. The weight percentage of the nickel-containing compound may range from 5% to 100% of the total active cathode material. The positive electrode is formed by combining and mixing the desired components of the electrode, followed by dispensing a quantity of the mixture into an open end of a container, and then forming the mixture into a solid tubular configuration using a ram, which defines a cavity within the container, and the separator 14 and first electrode 18 are then placed within the cavity (known as impact forming). The second electrode 12 has a ledge 30 and an inner surface 32, as shown in FIG. 1. Alternatively, the positive electrode may be formed by preforming a number of rings from a mixture containing the nickelate cathode material and then inserting the rings into a container to form a tubular shaped second electrode (known as ring molding). The cell shown in Figure 1 typically contains three or four rings.

[0091] The active material can be in the form of particles having any size suitable for use in the electrode mixture. In one embodiment, the active material is in the form of particles having an average size of approximately 1-20 microns, or 1-10 microns, or 1-5 microns, or 7-10 microns. In one embodiment, the active material is in the form of particles having a size in the range of 0.1-40 microns.

[0092] The cathode also includes a binder, which may be any binder known in the art. Non-limiting examples of binders include polyvinylidene fluoride (PVDF), polyethylene, polystyrene, and ethylene / propylene-based copolymers, such as those available under the trade name Kraton® sold by Kraton Corporation (Houston, TX), polytetrafluoroethylene (PTFE), poly(3,4-ethylenedioxythiophene) (PEDOT) copolymers, polystyrene sulfonate (PSS), and PEDOT:PSS polymer mixtures. The binder may be in the form of particles having any size suitable for use in the electrode mixture.

[0093] The cathode also includes a conductive material, which may be conductive carbon. The conductive carbon may be graphite, which may be expanded graphite. The graphite may be in the form of particles having any size suitable for use in the electrode mixture. In one embodiment, the graphite is in the form of particles having an average size ranging from nanoparticle size to 65 microns. In one embodiment, the maximum size of the graphite particles is 110 microns.

[0094] One example of an additional cathode additive is barium sulfate (BaSO4), commercially available from Bario E. Derivati ​​SpA of Massa, Italy. The barium sulfate is generally present in an amount of about 1 to about 2 weight percent, based on the total weight of the positive electrode. Other additives can include, for example, barium acetate, titanium dioxide, binders such as Coathylene® (Axalta Coating Systems, Glen Mills, PA), and calcium stearate.

[0095] One of the parameters utilized by cell designers characterizes the cell design as the ratio of the electrochemical capacity of one electrode to that of the opposing electrode, such as the ratio of anode (A) to cathode (C), i.e., the A:C ratio. For an LR6 type alkaline primary cell utilizing zinc in the negative electrode or anode and MnO2 in the positive electrode or cathode, the A:C ratio can be greater than 1.1:1, such as greater than 1.2:1, specifically 1.3:1, for impact molded positive electrodes. The A:C ratio for ring molded positive electrodes can be from about 1.3:1 to about 1.1:1.

[0096] The separator 14 is provided to separate the first electrode 18 from the second electrode 12. The separator 14 maintains a physical dielectric separation of the electrochemically active material of the positive electrode from the electrochemically active material of the negative electrode, allowing the transport of ions between the electrode materials. In addition, the separator functions as a wicking medium for the electrolyte and as a collar to prevent fragmented portions of the negative electrode from contacting the top of the positive electrode. The separator 14 may be a layered ion-permeable nonwoven fibrous fabric. A typical separator usually includes two or more layers of paper. Conventional separators are usually formed either by preforming the separator material into a cup-shaped basket and then inserting the cup-shaped basket under the cavity defined by the second electrode 12 and the closed end 24 and any positive electrode material thereon, or by forming the basket during cell assembly by inserting two rectangular sheets of separator into the cavity and rotating the materials at a 90° angle relative to each other. Conventional preformed separators typically consist of a sheet of nonwoven fabric rolled into a cylindrical shape that conforms to the inner wall of the second electrode and has a closed bottom end.

[0097] All of the references mentioned above, as well as all patents, patent publications, and non-patent references mentioned herein, are hereby incorporated by reference in their entirety.

[0098] Although the embodiments have been illustrated and described in detail above, such illustration and description are to be considered as illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those skilled in the art within the scope and spirit of the following claims. In particular, the embodiments include any combination of features from different embodiments described above and below.

[0099] The embodiments are further described by the following illustrative and non-limiting examples, which provide a better understanding of the embodiments and their many advantages. The following examples are included to demonstrate preferred embodiments. Those skilled in the art will appreciate that the techniques disclosed in the following examples represent techniques used in the embodiments to work well in practicing the embodiments, and therefore can be considered to constitute preferred modes for practicing the same. However, those skilled in the art will appreciate that in light of the present disclosure, many changes can be made to the specific embodiments disclosed and still obtain the same or similar results without departing from the spirit and scope of the embodiments.

[0100] Observations and Examples Example 1: NaNiO2 synthesis Granular Na2O2 ordered from Sigma Aldrich was poured into a Spex mill vial until it was one-third full. The material was pre-ground for 30 minutes to reduce particle size. The desired amount of Ni(OH)2 was weighed into a crucible and the crucible was covered with a lid. The Ni(OH)2 was heated in a furnace at 650°C for 6 hours to convert to NiO, which was verified by XRD. 13.1 g of converted NiO was weighed into a Spex mill container and 9.3 g of pre-ground Na2O2 was added. The Spex mill container was sealed with tape and ground for 5 minutes. The ground reagent mixture was transferred to a crucible with a lid and heated at 680°C in air or oxygen for 30 hours. If required, the final product was ground in a Spex mill for 10 minutes. The final product needs to be handled in an argon glove box since the samples are sensitive to moisture in air. The synthesized materials were analyzed for powder XRD patterns on a D-8 Advance X-ray diffractometer. As shown in Figure 3, the identified phases are mainly NaNiO2.

[0101] Example 2: Desodium / Disproportionation by Acid Leaching A 17.4 g sample from Example 1 was leached with concentrated sulfuric acid to remove sodium (desodium). After acid leaching, the sample was filtered through filter paper and washed with DI water until the pH of the filtrate matched that of the DI water. The powder was dried overnight at 71° C. The final weight of the dried sample was 2.2 g, which gives a calculated yield of about 13%. The dried powder was identified by XRD as sodium nickel oxide hydride (Na 0.33 The compound was identified as having mixed phases of nickel oxyhydroxide (NiO20.5(H2O), PDF 04-015-9998), nickel oxyhydroxide (beta-NiOOH, PDF 04-016-9895), and nickel oxide (NiO2, PDF 04-010-4751).

[0102] Example 3: Desodiumation and oxidation with persulfate 100 mL of deionized (DI) water was added to a 250 mL beaker. 43.2 g of Na2S2O8 purchased from GFS Chemical was slowly added to the beaker of DI water while stirring with a magnetic bar. The solution was continuously stirred until the solution was clear. 1.58 g of 50 wt% NaOH was slowly added and stirred for 1 hour. 9.0 g of NaNiO2 synthesized in Example 1 was added very slowly to the solution in the vent hood because the reaction is exothermic and adding the powder too quickly can result in foaming and overflowing (the resulting molar ratio of sodium persulfate to sodium nickel oxide is 2.3). When the powder addition was complete, the beaker with the stir set was transferred to a Thermotron oven and the temperature was increased to 40°C. The solution was continuously stirred at 40°C for 20 hours. The Thermotron was turned off and the powder was allowed to settle for 15-30 minutes until the powder settled. The powder was filtered through a filter paper and washed with DI water until the pH of the filtrate matched that of the DI water. The powder was dried overnight at 71° C. The final weight of the dried sample was 7.2 g, resulting in a yield of 80%, which is much higher than that in Example 2 (13%). The dried powder was identified by XRD as sodium nickel oxide hydride (Na 0.33The 2-theta of sample 2 in Figure 5 has been intentionally shifted 0.3 degrees to the right for better visualization.

[0103] Example 4: Alpha-nickelate Li x NiO2 synthesis A lithium nickel oxide (LiNiO2) precursor was prepared and delithiated in sulfuric acid solution by acid leaching (H. Arai and Y. Sakurai, J. Power Sources, 81-82 (1999) 401-405). XRD patterns showed that the delithiated product was alpha lithium nickel oxide (Li 0.09 Ni 0.01 )(NiO2, PDF 01-085-1976), and the composition was determined to be Li based on inductively coupled plasma atomic emission spectroscopy (ICP-AES). 0.104 It is NiO2.

[0104] Example 5: Half-cell testing on both fresh samples and samples aged for 4 weeks at 70° C. and 50% RH Several samples of the dry powders from both Examples 3 and 4 were aged at 70° C. and 50% relative humidity (RH) for 4 weeks. Both fresh and aged samples from Examples 3 and 4 were then discharged in a half-cell test fixture to determine the electrochemical discharge capacity as follows: 49% by weight of the active material was mixed with 49% SFG 15 graphite and 2% coatylene binder to form a cathode mixture. 200 mg of the cathode mixture was pressed into a 357 button cell can with a force of 5,000 lbf. The button cell was placed in an acrylic plastic test fixture filled with 40% by weight KOH and 6% by weight ZnO, and the button cell was discharged at a rate of 10 mA / g with a 1-hour break after every 5 hours of discharge to observe the voltage recovery. The discharge rate is based on the active material. FIG. 6 shows the discharge curves of the materials. From the figure, it can be seen that the alpha nickelate in Example 4 is approximately 10% higher than that in Example 3 (sodium nickel oxyhydroxide Na 0.33It can be seen that the alpha nickelate material from Example 4 has a higher fresh capacity (409 mAh / g at 1.0 V) cutoff voltage than the alpha nickelate material from Example 4 (347 mAh / g). However, the discharge capacity of the alpha nickelate material from Example 4 was rapidly reduced to 157 mAh / g after the sample was aged at 70° C. and 50% RH for 4 weeks. Under the same aging conditions, the discharge capacity of the sodium nickel hydride material from Example 3 was only slightly reduced to 327 mAh / g at 1.0 V. Thus, the sodium nickel hydride sample from Example 3, in addition to its high yield, is more chemically stable than the alpha nickelate material from Example 4.

[0105] Example 6: Beta-nickelate synthesis Beta nickelate was synthesized based on the method described in US 10,910,647 B2 as follows: 8.6 g of finely ground LiOH.H2O and 20.9 g of Ni(OH)2 were mixed using a ball mill. The mixture was transferred into an alumina boat. The furnace was heated from room temperature to 800°C under O2 flow at a rate of 5°C / min and kept at 800°C for 60 hours. The material was removed from the furnace after cooling and ground in a Spex for 6 minutes. The synthesized LiNiO2 powder was then delithiated with 6M H2SO4 at a weight ratio of 20:1 electrolyte to powder at a temperature of 1-4°C for 20 hours with continuous stirring. The delithiated solid was washed with deionized (DI) water until the supernatant was close to neutral (pH 6-7). The solid was collected by vacuum filtration and the material was dried at 60°C overnight. To convert the material to beta-nickelate, the powder was treated with 36 wt % KOH solution at a weight ratio of 3:1 powder to solution for 24 hours at room temperature. The solid was then washed with DI water and filtered until the filtrate was neutral. The collected solid was dried overnight at 71° C. The final material was confirmed as beta-nickelate based on the XRD spectrum in US 10,910,647 B2.

[0106] Example 7: Beta-nickelate pre-aged with LiOH Beta nickelate has been shown to have increased stability in concentrated KOH electrolyte compared to alpha nickelate (US9,793,542B2). However, the stability of beta nickelate is still inferior to that of electrolytic manganese dioxide (EMD), a conventional alkaline cathode material. In this application, the inventors have demonstrated that the stability of beta nickelate is improved by pre-aging with LiOH as follows. 40 mL of 1 M LiOH electrolyte was measured, and the LiOH solution was added to a vial containing 4 g of nickelate powder. The vial was swirled to ensure that all the powder was coated. It was left for 1 minute, then the contents of the vial were poured into a filter funnel, and DI water was used to transfer any remaining solids. The product was washed with DI water until the filtrate pH reached 10. When filtration was complete, the solid product was placed in an oven at 71 °C and dried overnight. As shown in Figure 7, several additional characteristic peaks are present in the XRD spectrum of beta nickelate after pre-aging compared to beta nickelate, at approximately 50.0 - 52.0, 53.6 - 56.8, 60.8 - 62.6, 66.4 - 67.5, and 67.4 - 68.6° 2 theta. These peaks are related to x Ni 1+y lithium and sodium nickel oxide compounds in the general form of MNiO2·nH2O, where M = Li or Na, 0 < x < 1, 0 < y < 0.2, and 0 ≤ n ≤ 1.

[0107] Example 8: Half-cell test comparison between pre-aged and non-pre-aged beta nickelate with O / C ratio = 1 Discharge of both pre-aged and non-pre-aged beta-nickelate was performed in a cathode half-cell test fixture to determine the electrochemical discharge capacity as follows: 49 wt% active material was mixed with 49 wt% SFG 15 graphite (oxide to carbon ratio (O / C)=1) and 2 wt% coathylene binder to form the cathode mixture. 200 mg of the cathode mixture was pressed into a 357 button cell can with a force of 5,000 lbf. The button cell was placed in an acrylic plastic test fixture filled with 40 wt% KOH and 6 wt% ZnO, and the button cell was discharged at a rate of 10 mA / g with a 1-hour pause after every 5-hour discharge to observe the voltage recovery. The discharge rate is based on the active material. Figure 8 shows the discharge curves of the materials. It can be seen that pre-aging with LiOH does not significantly affect the cathode discharge energy.

[0108] Example 9: Half-cell test comparison between pre-aged and non-pre-aged beta-nickelate with O / C ratio=14.5 mixed with EMD To test the cathode at an O / C ratio that more closely approximates realistic cell conditions, the beta-nickelate before and after pre-aging was mixed with Borman HD EMD, MX15 graphite, and coathylene binder at an O / C ratio of 14.5. The Ni content relative to the total Ni and Mn is 40 wt%, the combination of EMD and nickelate in the mixture is 93.1 wt%, the MX15 graphite is 6.4 wt%, and the coathylene (binder) is 0.5 wt%. The half-cell fixture and discharge protocol in this test are the same as in Example 8. However, the cathode in the half-cell test here was aged in an oven at 60° C. for up to 4 weeks and then discharged. The discharge curves at 10 mA / g are compared in FIG. 9. As can be easily seen from the figure, the pre-aged beta-nickelate is equivalent in discharge energy to the non-pre-aged beta-nickelate when the half-cell is fresh (0 weeks aging). However, the cells with the pre-aged nickelate have higher discharge voltages and energy throughout the discharge after both 1 week and 4 weeks of aging at 60° C. For example, after 1 week of aging at 60° C., the discharge energy density of the pre-aged nickelate to a 1.0 V cutoff is 394 mWh / g, which is higher than that of the non-pre-aged nickelate (382 mWh / g). Thus, pre-aging increases the beta-nickelate stability in high temperature storage, and cells with beta-nickelate pre-aged with LiOH are expected to have a longer storage life than non-pre-aged beta-nickelate.

[0109] Example 10: Half-cell discharge of persulfate desodium and sodium oxide nickelate (PS Na-nickelate) and comparison with beta-nickelate Discharge of the cathode with persulfate desodium and sodium oxide nickelate (PS Na-nickelate) was performed under the same conditions as in Example 9, and the cathode was compared with beta-nickelate in FIG. 10. From the discharge curves in FIG. 10, it can be seen that beta-nickelate has a higher discharge energy density (mWh / g) than PS Na-nickelate when the cathode is fresh (not high-temperature aged). However, after aging at 60° C., the energy density of PS Na-nickelate is consistently higher than beta-nickelate. For example, the energy density of PS Na-nickelate at 1.0 V is 1.5% less than beta-nickelate when the cathode is fresh (not high-temperature aged). However, the energy density of PS Na-nickelate at 1.0 V is 3.6% and 5.3% higher than beta-nickelate when the cathode is aged at 60° C. for 1 week and 4 weeks, respectively. Therefore, PS Na-nickelate as an alkaline cathode material is believed to have better service maintenance than beta-nickelate.

[0110] Example 11: Half-cell discharge of cathode with EMD / PS Na-nickelate mixture It is well known that materials containing nickel are much more expensive than EMD (MnO2), and it is more meaningful if a mixture of EMD and PS Na-nickelate can be used as a cathode material by taking advantage of low-cost EMD and high-performance nickelate. To investigate the synergistic effect of EMD and nickelate, a series of EMD / PS Na-nickelate mixtures with various levels of Ni weight % were evaluated in half-cell tests. The test equipment and cathode formulation are the same as above (e.g., O / C=14.5, and 93.1 wt.% total active material and 0.6 wt.% binder), and the discharge curves are shown in FIG. 11. It is not surprising that the cathode mixture with nickelate has a higher discharge voltage than the cathode with EMD, and the more nickelate, the higher the voltage. However, a cathode with a high nickelate level does not always have a higher energy than a cathode with a low nickelate level. For example, FIG. 11 shows that the discharge curves for cathodes with 80 wt % and 90 wt % nickel (relative to the total weight of nickel and manganese) crossed over with a cathode with 40 wt % nickel at a voltage of about 1.15 V. This is clearly seen in FIG. 12, which is a plot of energy density vs. Ni wt % up to 1.0 V. More importantly, FIG. 12 shows that the discharge efficiency at 20-40 wt % Ni is over 97%, and at 60-100 wt % Ni is in the range of 70%-87%. Therefore, it is more cost effective to have a cathode with a Ni wt % below 40 wt %. Discharge efficiency was the ratio of discharge capacity to 1.0 V (mAh / g) in FIG. 11 to the calculated EMD (285 mAh / g) and PS Na-nickelate discharge capacity (340 mAh / g) when discharged at O / C=1 and a rate of 10 mA / g, similar to the conditions in Example 8.

Claims

1. A nickelate hydride material having an X-ray diffraction (XRD) pattern including a set of first peaks at approximately 12° to 14°²θ, a second peak at approximately 18° to 21°²θ, a third peak at approximately 24° to 25°²θ, and a fourth peak at approximately 36° to 43°²θ. The aforementioned nickelate hydride material has the following phases: i) Sodium nickel oxide having the formula (Na x NiO 2 ・nH 2 O) in an amount of 40 to 90% by weight, wherein 0.2 ≤ x < 1 and 0 < n < 2, ii) Nickel oxide (NiO2) in an amount of 5 to 40% by weight, and iii) Nickelate material containing 5 to 20% by weight of beta-nickel hydroxide (NiOOH).

2. A method for preparing persulfate-treated desodium and oxidized nickellate, comprising contacting sodium nickellate with a persulfate solution to produce the persulfate-treated desodium and oxidized nickellate.

3. The method according to claim 2, wherein the persulfate-treated desodium and oxidized nickelate is a mixture of nickel oxide, sodium nickel oxide hydrate, and / or nickel hydroxide.

4. The persulfate-treated desodium and oxidized nickelate are the following phases: i) Formula (Na) in amounts of 40-90% by weight x NiO 2 nH 2 Sodium nickel oxide having O), wherein 0.2 ≤ x < 1 and 0 < n < 2, ii) Nickel oxide (NiO) in an amount of 5-40% by weight 2 ), and iii) The method according to claim 2 or 3, comprising 5 to 20% by weight of beta-nickel hydroxide (NiOOH).

5. The method according to claim 2 or 3, wherein the persulfate solution comprises a persulfate selected from the group consisting of potassium persulfate and sodium persulfate.

6. A pre-aged beta-nickelate material prepared by contacting beta-nickelate with a pre-aging solution containing hydroxide, the pre-aged beta-nickelate material having an X-ray diffraction (XRD) pattern including a first peak at about 50.0° to 52.0°²θ, a second peak at about 53.6° to 56.8°²θ, a third peak at about 60.8° to 62.6°²θ, a fourth peak at about 66.4° to 67.5°²θ, and a fifth peak at about 67.4° to 68.6°²θ.

7. The pre-aged beta-nickelate material according to claim 6, wherein the pre-aged beta-nickelate material comprises beta-nickelate, nickel oxide, beta-oxyhydroxide, or a combination thereof.

8. A method for preparing a pre-aged beta-nickelate material, comprising contacting a beta-nickelate with a pre-aging solution containing a hydroxide to produce the pre-aged beta-nickelate material.

9. The method according to claim 8, wherein the pre-aging solution comprises a hydroxide selected from the group consisting of LiOH, NaOH, and KOH.

10. An alkali cathode composition comprising the beta-nickelate material described in claim 6 and electrolytic manganese dioxide (EMD).

11. The composition according to claim 10, wherein the weight ratio of nickel to manganese is approximately 10:90 to 50:

50.

12. The composition according to claim 10, further comprising graphite and a binder.

13. The composition according to claim 12, wherein, with respect to the total weight of the nickelate, EMD, graphite, and binder, the nickelate material is present in an amount of about 8.8 to 45.1% by weight, the EMD is present in an amount of about 48 to 84.3% by weight, the graphite is present in an amount of about 3 to 8% by weight, and the binder is present in an amount of about 0.1 to 5% by weight.

14. The composition according to claim 12, wherein the total weight percentage of the combination of nickelate and EMD material is about 92 to 97% by weight, the graphite is present in an amount of about 2 to 7% by weight, and the binder is present in an amount of about 0.1 to 1.0% by weight.

15. An alkali electrochemical cell comprising a nickelate material according to any one of claims 1, 6, and 7, or a composition according to any one of claims 10 to 12.

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