EP4732354A2

EP4732354A2 - High energy, long cycle life cathode materials and cells employing the same

Info

Publication number: EP4732354A2
Application number: EP24826688.4A
Authority: EP
Inventors: Jennifer A. Nelson; Kenneth ROSINA; Sharon Dalton-Castor; Jack Treger; Kenan E. SAHIN
Original assignee: CAMX Power LLC
Current assignee: CAMX Power LLC
Priority date: 2023-06-22
Filing date: 2024-06-21
Publication date: 2026-04-29
Also published as: KR20260026085A; MX2025015436A; WO2024263841A3; WO2024263841A2

Abstract

Provided are electrochemically active materials, cathodes or electrochemical cells that include the electrochemically active materials, and processes of producing the electrochemical materials. Electrochemical materials as provided herein include a first composition of the formula Li1+aMO2+b (Formula I) where -0.3≤a≤1.3 and -0.3≤b≤1.3 and where M includes 30 at% to 70 at% Mn and 25 at% to 70 at% Ni, the first composition formed of a polycrystalline morphology including a plurality of crystallites and a grain boundary between adjacent crystallites, the grain boundary including a second composition of the formula Li1+aM'O2+b (Formula II) where -0.1≤a≤1.3 and -0.3≤b≤1.3, wherein the grain boundary includes one or more enrichment elements in at least a portion thereof, the one or more enrichment elements present at a higher atomic percentage in the portion than in an adjacent crystallite, wherein the one or more enrichment elements is Co, Al, or both Co and Al.

Description

HIGH ENERGY, LONG CYCLE LIFE CATHODE MATERIALS AND CELLS EMPLOYING THE SAME

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application depends from and claims priority to U.S. Provisional Application No: 63/522,514 filed June 22, 2023, U.S. Provisional Application No: 63/550,394 filed February 6, 2024, and U.S. Provisional Application No: 63/647199 filed May 14, 2024, the entire contents of each of which are incorporated herein by reference.

FIELD

[0002] Disclosed are polycrystalline metal oxides with improved cycle life and excellent specific energy, methods of manufacture thereof, and articles comprising the same.

BACKGROUND

[0003] The majority of current lithium ion batteries include one of two main types of cathode materials. The first are layered metal oxides having a rhombohedral layered a-NaFeO2 type structure (R-3M space group) with general formula LiMOz (M = usually a combination of Ni, Co, Mn, Al). To achieve high capacity, these cathodes contain a large percentage of Ni which is stabilized with Co and small amounts of other elements. Unfortunately, both Ni and Co are expensive with the latter also having environmental and supply issues. The second are olivine-type Lithium Iron Phosphate (LFP) materials. The LFP materials have an orthorhombic structure with Pmma space group (Y. Ikuhara, Nano Lett, 2016; 16: 5409-5414). LFP cathodes are considerably less expensive than LMO2 cathodes; however, they also have much lower capacity (-150 mAh/g as opposed to >200 mAh/g for LMO2 cathodes) and less than average discharge voltage (3.4V vs. Li as opposed to 3.8V vs. Li for LMO2 cathodes). Importantly, since iron is highly detrimental to layered metal oxide cathodes, the two cathode types cannot be produced in the same plant environment making it tricky for cathode suppliers currently producing LMO2 cathode materials to also produce LFP cathodes without great expense.

[0004] As such, new cathode materials are needed that combine high capacity retention and low cost, and can be manufactured using existing lithium ion cathode facilities. SUMMARY

[0005] The following summary is provided to facilitate an understanding of some of the innovative features unique to the present disclosure and is not intended to be a full description. A full appreciation of the various aspects of the disclosure can be gained by taking the entire specification, claims, drawings, and abstract as a whole.

[0006] Provided are electrochemically active materials that include: a first composition of the formula Lii+aMCh+b (Formula I) where -0.3<a<1.3 and - 0.3<b<l .3 and where M comprises 30 at% to 70 at% Mn and 25 at% to 70 at% Ni, said first composition formed of a polycrystalline morphology comprising a plurality of crystallites and a grain boundary between adjacent crystallites; the grain boundary comprising a second composition of the formula Lii iaM’Chib (Formula II) where -0.1<a<1.3 and -0.3<b<1.3; and wherein the grain boundary includes one or more enrichment elements in at least a portion thereof, the one or more enrichment elements present at a higher atomic percentage in the portion than in an adjacent crystallite, wherein the one or more enrichment elements includes or is selected from the group consisting of Co, Al, and both Co and Al. Optionally, M includes 30 at% to 65 at% Mn. In some aspects, the second composition has an a-NaFeOz-type structure, a cubic structure, a spinel structure, or a combination thereof. Optionally, the particle has a particle size of about 1 pm to about 25 pm. Optionally, the crystallites each independently have a particle size of less than about 1 pm. In any aspect, M optionally includes Co, optionally at greater than about 0 at% to about 15 at%, optionally about 0.01 at% to about 10 at%. Optionally, M includes Mn at about 30 at% to about 70 at%, Ni at about 25 at% to about 70 at%, greater than 0 to about 15 at% Co, and/or 0 to about 5 at% Mg, or any combination thereof. In other aspects, M includes about 30 at% to about 65 at% Mn, about 25 at% to about 70 at% Ni, greater than 0 to about 15 at% Co, and about 0 at% to about 5 at% Mg. In any aspect, the enrichment is optionally Co, Al, or includes both Co and Al. Optionally, Mn in the first composition is present at about 45 at% to about 65 at%. Optionally M includes Ni at less than or equal to 40 at%. In some aspects, M includes about 25 at% to about 70 at% Ni, about 0-15 at% Co, about 30 at% to about 65 at% Mn, and 0-10 at% additional elements. In any aspect, the grain boundary optionally includes the enrichment element at a higher atomic percentage than an average atomic percentage of the enrichment element in an adjacent crystallite. Optionally, M’ includes Mn at 30 at% to 70 at% relative to the total M’. Optionally, M’ includes Ni at about 10 atomic percent to about 70 atomic percent (at%) of total M’. Also provided are electrodes that include the electrochemically active material of any aspect as provided herein, a current collector in electrical contact with the electrochemically active material. Electrochemical cells are also provided that include a first electrode and a second electrode, the first electrode is the electrode according to any aspect as provided herein. Optionally, in the electrochemical cell the second electrode includes carbon or a lithium titanate, optionally where the carbon is or includes graphite. The electrochemical cell as provided herein optionally is characterized by a discharge capacity of greater than 140 mAh/g maintainable over 400 cycles or more, optionally greater than 160 mAh/g maintainable over 400 cycles or more, when cycled with (~2 mAh/cm² cathode loading) cycled at 45 °C from 2.7 - 4.2 V with average C-rate > 1, when said electrochemical cell comprises a graphite anode. The electrochemical cell as provided herein optionally is characterized by a discharge capacity of greater than 140 mAh/g maintainable over 400 cycles or more, optionally greater than 200 mAh/g maintainable over 400 cycles or more, when cycled with (~2 mAh/cm² cathode loading) cycled at 45 °C from 2.7 - 4.6 V with average C-rate > 1, when said electrochemical cell comprises a graphite anode. In an electrochemical cell, an electrolyte may exclude ethylene carbonate. Optionally, the electrolyte includes a lithium salt and dimethyl carbonate alone or in combination with one or more additives. Optionally, an additive in an electrolyte is fluoroethylene carbonate (FEC), difluoroethylene carbonate (F2EC), tris(trimethylsilyl)malonate (TMSM), tris(trimethylsilyl)phosphite (TMSPi), tris(trimethylsilyl)phosphate (TMSPO4), lithium bis(oxalato)borate (LiDFOB), and the co-solvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some aspects, additives optionally include combinations of fluoroethylene carbonate, difluoroethylene carbonate, lithium difluoro(oxalato)borate, or a combination thereof.

DRAWINGS

[0007] The aspects set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative aspects can be understood when read in conjunction with the following drawings. [0008] FIG. 1 illustrates a schematic of a polycrystalline particle with grain boundaries as described according to some aspects herein.

[0009] FIG. 2, illustrates (A) data for full cell cycling comparison between Comparison Example 1 and Example 2. Cells were cycled at 1C charge/ 1C discharge at 45 °C between 2.7 - 4.2V with graphite anode; and (B) Data for full cell cycling comparison between Comparison Example 2 and Example 2. Cells were cycles at 1C charge/ 1C discharge at 45 °C between 2.7 - 4.2V with graphite anode.

[0010] FIG. 3 illustrates XRD diffraction of Comparison Example 3. Peaks are consistent with a rhombohedral LiMCh structure with R-3M space group. Inset: shows expanded XRD pattern between 20° - 27° 20 showing a LizMnOs monoclinic structure consistent with high-Mn cathodes;

[0011] FIG. 4 illustrates full coin cell cycling for Comparison Example 4 and Example 4. Fig A - Cells were formed to 4.65V and cycled at 2.8- 4.3V at 45 °C on a rapid cycle test at an average 1C discharge with graphite anode. Fig B - Cells were formed to 4.65V and cycled at 2.8 - 4.6V or 2.8-4.3V at 45 °C on a rapid cycle test at an average 1C discharge with graphite anode.

[0012] FIG. 5 illustrates data for full cell cycling comparison between Comparison Example

5 and Example 5. Cells were formed to 4.65V and cycled at 2.8- 4.3V at 45°C on a rapid cycle test at an average 1C discharge with graphite anode.

[0013] FIG. 6 illustrates data for full cell cycling comparison between Comparison Example

6 and Example 6. Cells were formed to 4.65V and cycled at 2.8- 4.3V on a rapid cycle test at an average 1C discharge with graphite anode.

[0014] FIG. 7 illustrates data for full cell cycling comparison between Comparison Example

7 and Example 6. Cells were formed to 4.65V and cycled at 2.8-4.3V on a rapid cycle test at an average 1C discharge with graphite anode.

DETAILED DESCRIPTION

[0015] Provided are high Mn electrochemically active materials that may be used as actives in cathodes. It was found that by enriching grain boundaries with Co and combining this enrichment with a tailored amount of Mn that is well above that typically used in Mn containing cathode materials, that the capacity fade and/or rate capacity issues with prior Mn-rich cathode materials can be addressed. These grain boundary enriched Mn containing electrochemically active materials are on par with currently commercially available LFP cathodes, but have the great advantage over LFP of being amenable to manufacture using existing LMO2 electrode manufacturing facilities. The Mn-rich materials as provided herein are of high interest due to relatively low cost (reduced use of Co and Ni), environmental friendliness, and high thermal stability. The materials provided herein demonstrate improved rate capacity and/or resistance to voltage fade.

[0016] Also provided are electrochemical cells, optionally secondary cells, optionally lithium ion secondary cells, that include an anode, an electrolyte, and a cathode, the cathode comprising an electrochemically active cathode active material comprising a plurality of particles, said plurality of particles comprising a plurality of crystallites each including a first composition comprising lithium, manganese, and oxygen; a grain boundary between adjacent crystallites of the plurality of crystallites and comprising a second composition optionally having a layered a- NaFeCh-type structure, a cubic structure, a spinel structure, or a combination thereof; wherein a combination of a tailored amount of Mn and grain boundary enrichment with one or more enrichment elements achieves excellent cycle life and/or rate capacity.

[0017] Materials of the LiMO type where M is one or more metals alone or further with one or more additional elements, are dense, polycrystalline agglomerates of primary crystals (crystallites). These LiMO type materials are typically made using standard solid-state processes at temperatures in the range of 600 °C to 900 °C starting from a variety of precursor materials. Precursor materials are typically transition metal hydroxides (illustrated by the general formula M(0H)2), lithium precursors (e.g., Li OH or Li2C0.3), or inorganic precursors for other dopants (e.g., hydroxides, carbonates, nitrates). During heating of a precursor mixture including high Mn containing precursor material(s), polycrystalline LiM02 and Li2MnO.s are typically formed along with the expulsion of gases such as H2O, CO2 or NO2.

[0018] The result of the sintering action under the right conditions and with the proper precursors is the formation of one or more secondary particles that include within a plurality of primary crystallites that collectively form the larger secondary particle that may serve as the electrochemically active material. It was previously found that the regions between these primary crystallites, the grain boundaries, could be selectively enriched with Co as is found in U.S. Patent No. 9,209,455. In the present disclosure it was found that significant further improvements can be achieved by replacing some of the elements in the bulk material with relatively high, but tailored levels of Mn. Unexpectedly, when the levels of Mn used in this disclosure are combined with grain boundary enrichment, such is with Co, Al, or other enrichment element(s) as described herein, improved cycle life and power capabilities addressing the shortcomings of prior Mn-rich materials. Without being limited to one particular theory, it is understood that a synergistic relationship between grain boundary enrichment and the tailored amount of Mn is what produces the unique benefits of the materials as provided herein.

[0019] Accordingly, this disclosure provides improved electrochemically active materials such as those suitable for use in a cathode for a Li-ion secondary cell that, relative to prior high Mn-rich materials, improve cycle life and/or rate capacity. Also, provided are a variety of methods for achieving the cathode active materials and electrochemical cells that employ such materials in an electrode.

[0020] As used herein an “active material” is a material that is capable of participating in or participates in an electrochemical charge/discharge reaction of an electrochemical cell such as by absorbing or desorbing lithium.

[0021] As used herein, “absorbing” can mean: intercalation or insertion or conversion alloying reactions of lithium with the active materials.

[0022] As used herein, “desorbing” can mean: de-intercalation or de-insertion or conversion de-alloying reactions of lithium with the active materials.

[0023] As used herein, in the context of the Li-ion cell, cathode means positive electrode and anode means the negative electrode.

[0024] As shown in FIG. 1, disclosed is a particle comprising a crystallite 10 comprising a first composition, and grain boundary 20, 21 comprising a second composition, wherein a concentration of one or more enrichment elements, optionally Co or Al or both, in the grain boundary is greater than a concentration of that enrichment element in the crystallite. The particle comprises a plurality of crystallites and is referred to as a secondary particle. Optionally, a layer 30 may be disposed on an outer surface of the secondary particle to provide a coated secondary particle. [0025] The polycrystalline lithiated metal oxides as provided herein exhibit enhanced electrochemical performance and rate capacity. The compositions prevent the rapid capacity fade of prior electrochemically cycled Mn-rich materials and show cycle life further improved relative to LFP cathodes, while maintaining other desirable end-use article properties. Such grain boundary enriched high Mn containing materials may be readily manufactured by calcining a green body formulation including a LiOH and Mn and Ni containing hydroxide or carbonate precursors to form particles with defined grain boundaries and then enriching the grain boundaries with one or more enrichment elements such as Co or a combination of Co and Al, as illustrative examples, such that the resulting particles have more of the grain boundary enriching enrichment element than prior to enrichment and optionally greater than within the crystallites, the outer surfaces of which abut the edges of the grain boundaries in the secondary particle.

[0026] As such, provided are compositions, systems, and methods of making and using polycrystalline lithiated high Mn metal oxides having enriched grain boundaries as the means of achieving high initial discharge capacity and low capacity fade during cycling of electrochemical cells using the metal oxides as provided herein as an active component of a cathode, thereby overcoming prior challenges in high-Mn formulations.

[0027] The materials as provided herein include a particle comprising a plurality of crystallites each comprising a first composition. The particle formed of a plurality of crystallites may be referred to as a secondary particle. The particles as provided herein are uniquely tailored to have grain boundaries between the primary crystallites. Selectively enriching these grain boundaries, subsequent to their formation, such as with Co or Al as examples, results in particles that provide improved performance and cycle life of a cell incorporating the particles as a component of a cathode.

[0028] The particles are appreciated to include a grain boundary formed of or including a second composition, wherein a concentration of a enrichment element, for example, in at least a portion of the grain boundary is greater than a concentration of the enrichment element, for example, in the primary crystallite(s) adjacent thereto as measured by atomic percentage of the enrichment element relative to metals in each composition. The concentration of the enrichment element in the grain boundary containing such enrichment element is optionally greater than the enrichment element concentration within the adjacent crystallite(s) on average. The materials as provided herein are optionally relatively uniform in enrichment element within the crystallites. Whether uniform or not, the concentration of an enrichment element in the grain boundary is greater than the concentration of the enrichment element, individually or combined, as averaged within crystallite adjacent to the region of a grain boundary. Optionally, the provided first composition include a further outer coating layer may be disposed on an outer surface of the secondary particle to provide a coated secondary particle.

[0029] In some aspects of the presently provided particles, the first composition forming the crystallites (optionally referred to herein collectively as the bulk) includes polycrystalline layered- structure lithiated metal oxides defined by composition Lii+aMCh+b (Formula I) and optionally a cell or battery formed therewith, where -0.1<a<1.3 and - 0.3<b<l .3. In some aspects, a is -0.1, optionally 0, optionally 0.1, optionally 0.2 . Optionally, a is greater than or equal to -0.10, -0.09, -0.08, -0.07, -0.06, -0.05, -0.04, -0.03, -0.02, -0.01, 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.0, 1.1, 1.2, or 1.3. In some aspects, b is -0.3, optionally -0.2, optionally -0.1, optionally 0, optionally 0.1, optionally 0.2, optionally 0.3. Optionally, b is greater than or equal to -0.30, -0.29, -0.28, -0.27, -0.26, -0.25, -0.24, -0.23, -0.22, -0.21, -0.20, -0.19, -0.18, -0.17, -0.16, -0.15, -0.14, -0.13, -0.12, -0.11, -0. 10, -0.09, -0.08, -0.07, -0.06, -0.05, -0.04, -0.03, -0.02, -0.01, 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.0, 1.1, 1.2, or 1.3.

[0030] It is appreciated that in some aspects Li in Formula I need not be exclusively Li, but may be partially substituted with one or more elements selected from the group consisting of Mg, Sr, Na, K, and Ca. The one or more elements substituting Li, are optionally present at 10 atomic % or less, optionally 5 atomic % or less, optionally 3 atomic % or less, optionally no greater than 2 atomic percent, where percent is relative to total Li in an otherwise equivalent non-substituted material.

[0031] In the first composition in Formula I, M includes Mn at a tailored concentration. Mn is optionally present at about 30 at% to about 70 at% relative to the total M, or any value or range therebetween. It was found that at the benefits of grain boundary enrichment were not observed at concentrations of Mn lower than about 30 at%, more directly lower than about 35 at%, or higher than about 70 at%, optionally higher than about 65 at%. Thus, when Mn is present at about 30 at% to about 70 at% and much more enhanced at about 35 at% to about 65 at%, combined with grain boundary enrichment with one or more enrichment elements as also provided herein, optionally Co or Al, dramatic improvements in cycle life and/or rate capability are achieved relative to nongrain boundary enriched materials. As such, the materials of Formula I as provided herein as a first composition, or as a second composition further including enrichment with one or more enrichment elements, optionally include 30 at% to 70 at% Mn of the total M in Formula I, optionally 35 at% to 65 at% Mn. Optionally, Mn is present in M at or greater than about 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 or 64 at% and equal to or less than about 70, 69, 68, 67, 66, or 65 at%. Optionally, Mn is present in M about at or between 45 at% to 65 at%, 45 at% to 64 at%, optionally 45 at% to 63 at%, optionally 45 at% to 62 at%, optionally 45 at% to 61 at%, optionally 45 at% to 60 at%, optionally 40 at% to 70 at%, 40 at % to 65 at%, optionally 40 at% to 64 at%, optionally 40 at% to 63 at%, optionally 40 at% to 62 at%, optionally 40 at% to 61 at%, optionally 40 at% to 60 at%, optionally 35 at% to 65 at%, optionally 35 at% to 64 at%, optionally 35 at% to 63 at%, optionally 35 at% to 62 at%, optionally 35 at% to 61 at%, optionally 35 at% to 60 at%.

[0032] M in Formula 1 as provided in the first composition optionally includes Ni. The amount of Ni in the first composition is optionally from 25 atomic percent to 70 atomic percent (at%) of total M. Optionally, the Ni component is equal to or less than 65 at%. Optionally, the Ni component is less than or equal to 60 at%. Optionally, the Ni component is less than or equal to 40 at%. Optionally, the Ni component is less than or equal to 35 at%. Optionally, the Ni component is less than or equal to 30 at%. Optionally, the Ni component of M is less than or equal to 70, 65, 60, 55, 50, 45, 40, 35, 30, 25 at%. In some aspects Ni is absent.

[0033] The sum of the at% of Ni and the at% of Mn in the first composition, the second composition or both is optionally equal to or greater than 70 at%. Optionally, the sum of the at% of Ni and the at% of Mn in the first composition, the second composition or both is optionally equal to or greater than about 75 at%, optionally 76 at%, optionally 77 at%, optionally 78 at%, optionally 79 at%, optionally 80 at%, optionally 81 at%, optionally 82 at%, optionally 83 at%, optionally 84 at%, optionally 85 at%, optionally 86 at%, optionally 87 at%, optionally 88 at%, optionally 89 at%, optionally 90 at%, optionally 91 at%, optionally 92 at%, optionally 93 at%, optionally 94 at%, optionally 95 at%, optionally 96 at%, optionally 97 at%, optionally 99 at%, optionally in the first composition 100 at%.

[0034] In some aspects, M in the first composition is Mn with Ni alone, or with Ni or Co or both in combination optionally with one or more additional elements, or Mn in combination optionally with one or more additional elements. The additional elements are optionally metals. Optionally, an additional element may include or be one or more of Al, Mg, Co, Mn, Ca, Sr, Zn, Ti, Y, Cr, Mo, Fe, V, Si, Ga, or B. In some aspects, the additional element may include Mg, Co, Al, or a combination thereof. Optionally, the additional element may be Mg, Al, V, Ti, B, or a combination thereof. Optionally, the additional element is selected from the group consisting of Mg, Al, V, Ti, or B. Optionally, the additional element selected from the group consisting of Co, and Al. Optionally, the additional element selected from the group consisting of Ca, Co, and Al. Optionally, the additional element is Co.

[0035] An additional element(s) of the first composition may be present in an amount of about 1 at% to about 55 at%, specifically about 5 at% to about 55 at%, more specifically about 10 at% to about 55 at% of M in the first composition. Optionally, the additional element may be present in an amount of about 1 at% to about 20 at%, specifically about 2 at% to about 18 at%, more specifically about 4 at% to about 16 at%, of M in the first composition. In some illustrative examples, M is about 25-70 at% Ni, about 0-15 at% Co, about 30-70 at% Mn, and about 0-10 at% additional elements. In examples, M is about 25-70 at% Ni, 0-15 at% Co, 30-70 at% Mn, and 0- 10 at% additional elements where the sum of Ni and Mn is equal to or greater than 75 at%. In some illustrative examples, M is about 30-50 at% Ni, 0.01-10 at% Co, 30-70 at% Mn, and 0-10 at% additional elements. Optionally, M comprises about 30 at% to about 70 at% Mn and about 25 to about 50 at% Ni where the sum of Mn and Ni is at least 80 at%, about 0 to about 15 at% Co, and about 0 at% to about 5 at% Mg. Optionally, M comprises about 30 at% to about 70 at% Mn, about 25 to about 50 at% Ni, about 0 to about 15 at% Co, and about 0 at% to about 5 at% Mg. It is appreciated that the at% of total M equals 100.

[0036] In some aspects, the first composition portion forming the crystallites in part or in whole optionally has the layered a-NaFeCh-type structure, a cubic structure, a spinel structure, or a combination thereof. [0037] In particular aspects, a secondary particle has an enriched grain boundary, optionally where the atomic percentage of one or more enrichment elements in the grain boundary is higher than the atomic percentage of the same elements in the crystallites, optionally as averaged throughout the crystallites, optionally as averaged in the adjacent cry stallite(s). Referring to FIG. 1 as an exemplary illustration, the grain boundary 20, 21 is between adjacent crystallites 10, and includes the second composition. A second composition may be as described in U.S. Pat. Nos. 9,391,317 and 9,209,455 with the exception that any enrichment element as described herein may be independently enriched in the grain boundary relative to the concentration of that enrichment element each independently in the crystallites and must be combined with the tailored amount of Mn as provided herein.

[0038] In some aspects, the second composition forming the grain boundary in part or in whole optionally has the layered a-NaFeCh-type structure, a cubic structure, a spinel structure, or a combination thereof. As noted above, a concentration of one or more enrichment elements in the grain boundaries may be greater than a concentration of the one or more enrichment elements in the crystallites. An aspect in which the grain boundaries have the layered a-NaFeCh-type structure is specifically mentioned. Another aspect in which the grain boundaries with a-NaFeCh- type structure with defects is specifically mentioned. Another aspect in which parts of the grain boundaries have a cubic or spinel structure is specifically mentioned.

[0039] More specifically, the Mn-rich LiMO materials as provided herein are optionally consistent with a LiMCh structure with R-3M space group. In some aspects, the crystallites, grain boundary or both include a mix of phases also including a Li?MnO3 monoclinic structure. Thus, in some aspects, the materials as provided herein are optionally a heterogeneous mix of phase structures. In some aspects, a material as provided herein includes a grain boundary with a predominant of LiMCh structure with R-3M space group, optionally a grain boundary entirely with a LiMCh structure with R-3M space group. In some aspects, a material as provided herein includes a plurality of crystallites with a predominant of LiMCh structure with R-3M space group, optionally a plurality of crystallites entirely with a LiMCh structure with R-3M space group. In some aspects, the grain boundary, crystallites or both includes a mix of LiMO structure and Li?M03 structure. Optionally, a Li?M03 structure is a layered-layered Li2MOs- LiMO? structure. [0040] The second composition as present in part or in whole in the grain boundaries optionally includes lithiated metal oxides defined by composition Lii+aM’Ch+b (Formula II) where -0.1<a<1.3 and -0.3<b<1.3. Optionally, a second composition and a first composition are identical with the exception of the presence of or increased concentration of one of more enrichment elements, optionally Co, Al, or both Co and Al, in the second composition relative to the first composition. In some aspects of the second composition, a is -0.1, optionally 0, optionally 0.1, optionally 0.2, optionally 0.3, optionally 0.4, optionally 0.5, optionally 0.6, optionally 0.7, optionally 0.8, optionally 0.9, optionally 1.0, optionally 1.1, optionally 1.2. or optionally 1.3. Optionally, a is greater than or equal to -0.10, -0.09, -0.08, -0.07, -0.06, -0.05, -0.04, -0.03, -0.02, -0.01, 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.0, 1.1, 1.2, or 1.3. In some aspects, b is ^_0.3, optionally -0.2, optionally —0.1, optionally 0, optionally 0.1, optionally 0.2, optionally 0.3, optionally 0.4, optionally 0.5, optionally 0.6, optionally 0.7, optionally 0.8, optionally 0.9, optionally 1.0, optionally 1.1, optionally 1.2. or optionally 1.3. Optionally, b is greater than or equal to -0.30, -0.29, -0.28, -0.27, -0.26, -0.25, -0.24, -0.23, -0.22, -0.21, -0.20, -0.19, -0.18, -0.17, -0.16, -0.15, -0.14, -0.13, -0.12, -0.11, -0.10, -0.09, -0.08, -0.07, -0.06, -0.05, -0.04, -0.03, -0.02, -0.01, 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.0, 1.1, 1.2, or 1.3.

[0041] In Formula II, similar to Formula I, M’ optionally includes Mn at a tailored concentration. Mn is optionally present at 10 at% to 70 at% relative to the total M’, or any value or range therebetween. The materials of Formula II as provided herein optionally include 10 at% to 70 at%, optionally 30 at% to 70 at% Mn of the total M’ in Formula II, optionally 35 at% to 65 at% Mn. Optionally, Mn is present in M’ at or greater than 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, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 or 64 at% and equal to or less than about 70, 69, 68, 67, 66, or 65 at%. Optionally, Mn is present in M’ about at or between 45 at% to 65 at%, 45 at% to 64 at%, optionally 45 at% to 63 at%, optionally 45 at% to 62 at%, optionally 45 at% to 61 at%, optionally 45 at% to 60 at%, optionally 40 at% to 70 at%, 40 at % to 65 at%, optionally 40 at% to 64 at%, optionally 40 at% to 63 at%, optionally 40 at% to 62 at%, optionally 40 at% to 61 at%, optionally 40 at% to 60 at%, optionally 35 at% to 65 at%, optionally 35 at% to 64 at%, optionally 35 at% to 63 at%, optionally 35 at% to 62 at%, optionally 35 at% to 61 at%, optionally 35 at% to 60 at%. In some aspects, Mn is absent in a second composition.

[0042] In Formula II, M’ optionally includes Ni. Ni is optionally present at 10 at% to 70 at% relative to the total M’, or any value or range therebetween. The materials of Formula II as provided herein optionally include 10 at% to 70 at%, optionally 25 at% to 70 at% Ni of the total M’ in Formula II. Optionally, Ni is present in M’ at or greater than 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, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, or 70 at%. Optionally, Ni is present in M’ at or less than 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, 46,

47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, or 70 at%.

Optionally, Ni is absent in a second composition.

[0043] Examples of enrichment elements that can potentially be included in M’ of Formula II to form grain boundary enriched secondary particles include a variety of elements that can substitute for Ni in the structure. If, for example, trivalent (3+) ions of doping elements that can directly substitute for Ni³ are less easily oxidized than the Ni ions when the material is charged, they will promote the beneficial cycling characteristics observed with the materials as described herein; substitution of Ni(III) by Al(III) is an example. If tetravalent (4+) ions substitute for Ni³⁺, they are charge-compensated by Ni ions in the 2+ state and their inductive effects raise the potential for oxidation of those Ni ions to the 4+ state; substitution of Ni(III) by Mn(IV) is an example. Alternatively, if difficult to oxidize 2+ ions substitute for Ni, they are charge-compensated by Ni ions in the 4+ state; substitution of Ni (III) by Mg (II) is an example. In order to substitute for Ni in the LiM’Ch structure, doping ions may be of size comparable to that of the Ni ions, and they may raise the local oxidation potential. The relative impact of a given ion’ s impact on the oxidation potential can often be estimated from its ionization energy relative to that of Ni³⁺. Therefore, ions of size comparable to Ni³⁺ and having comparable or higher ionization energy can potentially serve to stabilize oxidized cathodes’ grain boundaries. The following table provides the ionization energies and hexacoordinate (octahedral environment) ionic radii for examples of ions that might stabilize the grain boundaries of charged high-Ni LiMCh cathode materials.

Table 1: Oxidation potentials and ionic radii for elements*

*ionization energy

[0044] As such, in the second composition, M’ further includes one or more enrichment elements that may be selected from a group that oxidize less than nickel when electrochemically charged to 4.3V or higher relative to Li metal anode. In one example, M’ can comprise Ni and a combination of Co and Mn, which oxidizes less than nickel when charged to 4.3V or higher, optionally 4.6 V. In other aspects, M’ may include Ni, Mn and one more elements selected from the group comprising Cr, Fe, Ti, V, Co, Cu, Zn, Zr, Nb, Sb, W, Sc, Al, Mo, Y, etc., which oxidize less than Ni when charged to 4.3V relative to lithium metal. Optionally, M’ excludes the combination of Ni with Co alone, Al alone, or a combination of Co and Al, and Co, Al, or both may be present with doping of one or more additional enrichment elements as provided herein. In some aspects, M’ may include an element selected from the group of elements that will not oxidize when charged to 4.3V relative to lithium such as Y, Sc, Ga, In, Tl, Si, Ge, Sn, Pb, etc.

[0045] M’ as provided in the second composition optionally includes one or more enrichment elements, optionally Co, Al, or both, at a higher concentration than such element in the crystallites as described herein.

[0046] Optionally, Li in the second composition (grain boundary) need not be exclusively Li, but may be partially substituted with one or more Li-enrichment elements selected from the group consisting of Mg, Sr, Na, K, and Ca. The one or more Li-enrichment elements, are optionally present at 10 atomic % or less, optionally 5 atomic % or less, optionally 3 atomic % or less, optionally no greater than 2 atomic percent, where percent is relative to total Li in the as-made material.

[0047] For the materials optionally as provided herein, the nominal or overall formulated composition of the secondary particles (for example, characterized by elemental mapping from SEM), optionally the first composition, or optionally the second composition, or both is defined by the general formula LiMO, wherein M is Mn and Ni and optionally one or more additional elements wherein the second composition must include one or more enrichment elements. As an example, the mole fraction of Co and/or Al, if present, as defines the composition of the crystallites, is lower than the mole fraction of the total Co and/or Al independently or combined in the total particle composition as determined by elemental mapping. The mole fraction of the enrichment element independently or combined in the crystallites can be zero. The mole fraction of the enrichment element in the grain boundary independently or combined is higher than the mole fraction of that enrichment element independently or combined in the total particle as measured by elemental mapping. It is noted that this is an example alone as the Co, Al, or both may be instead or in addition one or more other enrichment elements as illustrated herein.

[0048] A second composition located within the grain boundaries includes Co or Al or one or more other enrichment elements, optionally with the condition that the concentration of Co or Al or one or more other enrichment elements independently or combined in the grain boundary is greater than the concentration of Co or Al or one or more other enrichment elements independently or combined in the crystallites, optionally where the concentration of Co in the grain boundary is greater than the concentration of Co in the crystallites, and optionally where the concentration of Al in the grain boundary is greater than the concentration of Al in the crystallites, or one or more other enrichment elements at a concentration greater than the concentration of the one or more enrichment elements in the crystallites. As a non-limiting example, it was found that using processes that are capable of enriching an enrichment element in the grain boundaries, liquid solutions that included amounts relative to the total transition metal of the first composition to be enriched of Co of at or between 0 at% and 8 at%, optionally at or between 3 at% and 5 at% Co could be supplemented with 0.01 at% to 10 at% Al, optionally 1.5 at% or less Al, where the added Co and Al are incorporated into the grain boundaries of the secondary particle.

[0049] The volume fraction of grain boundaries within a given secondary particle will vary because the primary particle size distribution varies with variations in overall composition and synthetic conditions, and accordingly, the final concentration of the one or more enrichment elements in the grain boundary can vary between different secondary particles and within individual secondary particles as well, while still always being greater than the concentrations of the one or more enrichment elements in the adjacent or total crystallites. It is thus most useful that the amount of an enrichment element added to the grain boundary be defined relative to the formulation of the crystallite. In some aspects, the amount of the one or more enrichment elements is similar to that described for Co in U.S. Patent No: 11,424,449 or U.S. Patent No: 10,501,335, but in this disclosure and crystallites and optionally the grain boundaries also further include Mn at or about the tailored concentration as otherwise described herein.

[0050] An electrochemically active material as provided herein may be in the form of a secondary particle. A secondary particle has a particle size defined as the size of a secondary particle measured from outside edge to opposing outside edge and passing substantially through a center of the secondary particle. A particle size or average particle size (overall average of all particles of the same composition) of a first composition is optionally from about 1 pm to about 25 pm, or any value or range therebetween. Optionally, a first composition has a particle size or average particle size of about 1 pm, optionally about 2 pm, optionally 3 pm, optionally about 4 pm, optionally 5 pm, optionally about 6 pm, optionally 7 pm, optionally about 8 pm, optionally 9 pm, optionally about 10 pm, optionally 11 pm, optionally about 12 pm, optionally 13 pm, optionally about 14 pm, optionally 15 pm, optionally about 16 pm, optionally 17 pm, optionally about 18 pm, optionally 19 pm, optionally about 20 pm, optionally 21 pm, optionally about 22 pm, optionally 23 pm, optionally about 24 pm, optionally 25 pm. Optionally, a particle size or average particle size of a first composition is from about 1 pm to about 15 pm, optionally about 1 pm to about 10 pm.

[0051] Each crystallite may have any suitable shape, which can be the same or different within each secondary particle. Further, the shape of each crystallite can be the same or different in different secondary particles. Because of its crystalline nature, the crystallite may be faceted, the crystallite may have a plurality of flat surfaces, and a shape of the crystallite may approximate a geometric shape. In some aspects, the crystallite may be fused with neighboring crystallites with mismatched crystal planes. The crystallite may optionally be a polyhedron. The crystallite may have a rectilinear shape, and when viewed in cross- section, a portion of or an entirety of the crystallite may be rectilinear. The crystallite may be square, hexagonal, rectangular, triangular, or a combination thereof. A length, a width, and a thickness of the crystallite may be selected independently, and each of the length, width, and thickness of the crystallite may be about 5 to about 1000 nanometers (nm), specifically about 10 to about 900 nm, more specifically about 20 to about 800 nm.

[0052] The materials as provided herein may be prepared by synthesizing a green body from at least two components, optionally in powder form. At least two components may include micronized (or non-micronized) lithium hydroxide or its hydrate and a precursor hydroxide(s) comprising Mn and optionally one or more other elements, and where the precursor hydroxides are optionally obtained by co-preci pi tati on processes. By tailoring the conditions under which the formation of the metal hydroxide is formed, one can then produce an electrochemically active material as provided herein.

[0053] In some aspects, the precursor hydroxide may be a mixed metal hydroxide. In some aspects, the mixed metal hydroxide may include a metal composition of Mn in combination with Ni and optionally Co. Optionally, the mixed metal hydroxide includes as a metal component 30- 70 at% Mn, 25-70 at% Ni, 0 - 15 at% Co, and 0 - 5 at% Mg. Optionally the mixed metal hydroxide includes Ni from 25-70 at%, Co in the range of 0-30 at%, and Mn in the range of 30- 70. Optionally the mixed metal hydroxide includes Ni from 25-70 at%, Co in the range of 0-30 at%, Al in the range of 0-10 at%, and Mn in the range of 30-70 at%. Optionally the mixed metal hydroxide includes Ni from 25-70 at%, Co in the range of 0-30 at%, Al in the range of 0-10 at%, and Mn in the range of 30-70 at%. Optionally the mixed metal hydroxide includes Ni from 35-65 at%, Co in the range of 0-30 at%, Al in the range of 0-10 at%, and Mn in the range of 35-65 at%. Optionally, the metals of the mixed metal hydroxide is about 40 at% Ni, about 56 at% Mn, and about 4 at% Co. Optionally, the metals of the mixed metal hydroxide is about 61 at% Ni, about 35 at% Mn, and about 4 at% Co. Optionally, the metals of the mixed metal hydroxide is about 26 at% Ni, about 70 at% Mn, and about 4 at% Co. Optionally, the metals of the mixed metal hydroxide is about 31 at% Ni, about 65 at% Mn, and about 4 at% Co. Optionally, the metals of the mixed metal hydroxide is about 36 at% Ni, about 60 at% Mn, and about 4 at% Co. For example, precursor hydroxide may be made by a precursor supplier, such as Hunan Brunp Recycling Technology Co. Ltd., using standard methods for preparing nickel-hydroxide based materials.

[0054] A secondary particle may be formed by a multi-step process whereby a first material particle is formed and calcined so as to establish the formation of defined grain boundaries optionally with the primary particles having oc-NaFeCh structure with few or no observable defects. The particles are then subjected to a liquid process that applies one or more enrichment elements, optionally Co, at the desired concentration levels followed by drying and then a heat treatment so as to move the enrichment element precipitated species at the surface selectively into the grain boundaries to thereby form the secondary particle having a concentration of the enrichment element, optionally Co and/or Al, in the grain boundaries that is higher than in the crystallites. According to methods of manufacturing a secondary particle that has a base of Ni, Co, and Mn with high Mn levels as provided herein as an example, formation may include: combining a lithium compound, and a hydroxide precursor compound of one or more metals or metalloids (e.g. Ni, Co, and Mn combined as previously generated such as by a co-precipitation reaction) to form a mixture; heat treating the mixture at about 30 to about 200 °C to form a dried mixture; heat treating the dried mixture at about 200 to about 500 °C for about 0.1 to about 5 hours; then heat treating at 600 °C to less than about 1000 °C for about 0.1 to about 10 hours to manufacture the secondary particle. A first calcination maximum temperature is relative and specific to the material used in the hydroxide precursor. Optionally, in a first calcination, a maximum temperature may be at or less than 950 degrees Celsius, optionally at or less than 900 degrees Celsius, optionally at or less than 850 degrees Celsius, optionally at or less than 800 degrees Celsius, optionally at or less than 750 degrees Celsius, optionally at or less than 720 degrees Celsius, optionally at or less than 715 degrees Celsius, optionally at or less than 710 degrees Celsius, optionally at or less than 705 degrees Celsius, optionally at or less than 700 degrees Celsius. Optionally, the maximum temperature of the first calcination may be about 1000 degrees Celsius or less. Optionally, the maximum temperature may be about 950 degrees Celsius or less. Optionally, the maximum temperature may be about 900 degrees Celsius or less. Optionally, the maximum temperature may be about 850 degrees Celsius or less. Optionally, the maximum temperature may be about 800 degrees Celsius or less. Optionally, the maximum temperature may be about 750 degrees Celsius or less. Optionally, the maximum temperature may be about 700 degrees Celsius or less. Optionally, the maximum temperature may be about 660 degrees Celsius or less. Optionally, the maximum temperature may be about 640 degrees Celsius or less. In yet other aspects, the maximum temperature may be less than about 700 degrees Celsius, about 695 degrees Celsius, about 690 degrees Celsius, about 685 degrees Celsius, about 680 degrees Celsius, about 675 degrees Celsius, about 670 degrees Celsius, about 665 degree Celsius, about 660 degrees Celsius, about 655 degrees Celsius, about 650 degrees Celsius, about 645 degrees Celsius, or about 640 degrees Celsius. The dwell time at the maximum temperature is optionally less than 10 hours. Optionally, the dwell time at the maximum temperature is less than or equal to 8 hours; optionally less than or equal to 7 hours; optionally less than or equal to 6 hours; optionally less than or equal to 5 hours; optionally less than or equal to 4 hours; optionally less than or equal to 3 hours; optionally less than or equal to 2 hours.

[0055] After calcination, subsequent processing may include breaking up the calcined material with a mortar and pestle so that the resulting powder passes through a desired sieve, optionally a #35 sieve. The powder is optionally then jar milled in a 1 gallon jar with a 2 cm drum YSZ media for optionally 5 minutes or an adequate time such that the material may pass through optionally a #270 sieve.

[0056] The product of the first calcination or milled product may be subsequently processed, optionally in a method so as to result in enriched grain boundaries following a second calcination. A process to enrich grain boundaries within a primary particle may be performed by methods or using compositions as illustrated in U.S. Patent Nos. 9,391,317 and 9,209,455 with the exception that the application process uses a liquid solution that includes a level of enrichment element, optionally Co and/or a level of Al. The grain-boundary-enriching elements may optionally be applied by suspending the milled product in an aqueous slurry comprising the one or more enrichment elements, and a lithium compound optionally at a temperature of about 60 degrees Celsius whereby the enrichment elements, optionally Co and/or Al, are present in the aqueous solution at the concentrations as described herein. The slurry may then be spray dried to form a free-flowing powder which is then subjected to a second calcination optionally with a heating curve following a two ramp/dwell process. The first two ramp/dwell temperature profile may be from ambient (about 25 degree Celsius) to 450 degrees Celsius and optionally at a rate of 5 degree Celsius per minute with a 1 hour hold at 450 degrees Celsius. Subsequently, the second ramp/dwell may be from 450 degrees Celsius to a maximum temperature at a rate of 2 degree Celsius per minute with a 2 hour hold at the maximum temperature. In some aspects, the maximum temperature is less than about 725 degrees Celsius, optionally at or about 700 degrees Celsius. In other aspects, the maximum temperature is about 700 degrees Celsius, optionally 750 degrees Celsius.

[0057] By combining a first calcination with a maximum temperature as described above with a process to apply grain-boundary-enriching elements followed by a second calcination also as described above, it was found that the resulting particles with a tailored Mn concentration could be used in a cathode so as to produce significantly improved reductions in capacity fade and/or increases in rate capability. Such a combination was found to result in additional cycle life significantly improving the electrochemical performance of the material while simultaneously dramatically reducing the cost relative to prior high Ni and Co materials. As such, it is appreciated that in some aspects, a particle includes a plurality of crystallites with a first composition including poly crystalline layered- structure lithiated metal oxides defined by composition Lii+aMCh+b where -0.1<a<1.3 and - 0.3<b<1.3. In some aspects a is -0.1, optionally 0, optionally 0.1, optionally 0.2, optionally 0.3, optionally 0.4, optionally 0.5, optionally 0.6, optionally 0.7, optionally 0.8, optionally 0.9, optionally 1.0, optionally 1.1, optionally 1.2. or optionally 1.3. Optionally a is greater than or equal to -0.10, -0.09, -0.08, -0.07, -0.06, -0.05, -0.04, -0.03, -0.02, -0.01, 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17,

0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.40, 0.50, 0.60, 0.70,

0.80, 0.90, 1.0, 1.1, 1.2, or 1.3. In some aspects, b is -0.3, optionally -0.2, optionally -0.1, optionally 0, optionally 0.1, optionally 0.2, optionally 0.3, optionally 0.4, optionally 0.5, optionally

0.6, optionally 0.7, optionally 0.8, optionally 0.9, optionally 1.0, optionally 1.1, optionally 1.2. or optionally 1.3. Optionally, b is greater than or equal to -0.30, -0.29, -0.28, -0.27, -0.26, -0.25, -0.24, -0.23, -0.22, -0.21, -0.20, -0.19, -0.18, -0.17, -0.16, -0.15, -0.14, -0.13, -0.12, -0.11, -0.10, -0.09, -0.08, -0.07, -0.06, -0.05, -0.04, -0.03, -0.02, -0.01, 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.0, 1.1, 1.2, or 1.3. The crystallites have a concentration of Mn. Mn is optionally present at 30 at% to 70 at% relative to the total M, or any value or range therebetween. It was found that at the benefits of grain boundary enrichment were not observed at concentrations of Mn lower than 30 at%, more directly lower than 35 at%, or higher than 70 at%, optionally higher than 65 at%. The first composition optionally includes 30 at% to 70 at% Mn of the total M, optionally 35 at% to 65 at% Mn. Optionally, Mn is present in M at or greater than 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 or 64 at% and equal to or less than, 70, 69, 68, 67, 66, or 65 at%. Optionally, Mn is present in M at or between 45 at% to 65 at%, optionally 40 at% to 70 at%, optionally, 35 at% to 70 at%, optionally 35 at% to 65 at%, optionally 35 at% to 61 at%, optionally 35 at% to 60 at%. The crystallites have an amount of Ni of 25 atomic percent to 70 atomic percent (at%) of the M element. The amount of Ni in the first composition is optionally from 25 atomic percent to 69 atomic percent (at%) of total M. Optionally, the Ni component is equal to or less than 65 at%. Optionally, the Ni component is less than or equal to 60 at%. Optionally, the Ni component is less than or equal to 40 at%. Optionally, the Ni component is less than or equal to 35 at%. Optionally, the Ni component is less than or equal to 30 at%. Optionally, the Ni component of M is less than or equal to 70, 65, 60, 55, 50, 45, 40, 35, 30, 25 at%. The M component may include one or more additional elements. The additional elements are optionally metals. Optionally, an additional element may include or be one or more of Al, Mg, Co, Mn, Ca, Sr, Zn, Ti, Y, Cr, Mo, Fe, V, Si, Ga, or B. In particular aspects, the additional element may include Mg, Co, Al, or a combination thereof. Optionally, the additional element may be Mg, Al, V, Ti, B, or a combination thereof. Optionally, the additional element consists of Mg, Al, V, Ti, B. The additional element of the first composition may be present in an amount of about 1 to about 90 at%, specifically about 5 to about 80 at%, more specifically about 10 to about 70 at% of the first composition. Optionally, an additional element of the first composition may be present in an amount of about 0 to about 70 at%, specifically about 5 to about 70 at%, more specifically about 10 to about 70 at% of M in the first composition. Optionally, the additional element may be present in an amount of about 1 to about 20 at%, specifically about 2 to about 18 at%, more specifically about 4 to about 16 at%, of M in the first composition. In such materials, the grain boundaries may be enriched with one or more enrichment elements, optionally Co, Al, or both, optionally at 0.1 to 10 at% higher than the concentration of the one or more enrichment elements in the crystallites.

[0058] An electrochemical cell as provided herein optionally uses as an electrochemically active material particles as provided herein optionally having an initial discharge capacity of 110 mAh/g of the particles or greater, optionally 120 mAh/g, optionally 130 mAh/g, optionally 140 mAh/g, optionally 150 mAh/g, optionally 160 mAh/g, optionally 170 mAh/g, optionally 180 mAh/g, optionally 190 mAh/g, optionally 200 mAh/g, optionally 210 mAh/g, optionally 220 mAh/g, optionally 230 mAh/g, optionally 240 mAh/g, optionally 250 mAh/g.

[0059] As shown in FIG. 1, disclosed is a particle comprising a crystallite 10 comprising a first composition, and grain boundaries 20, 21 comprising a second composition, wherein a concentration of one or more enrichment elements, optionally Co, Al or a combination thereof, in the grain boundary is greater than a concentration of the one or more enrichment elements in the crystallites. The particle comprises a plurality of crystallites and is referred to as a secondary particle. Optionally an outer layer illustrated at 30 in FIG. 1, such as a passivation layer or a protective layer, may be deposited on an outer surface of the particle. The outer layer may fully or partially cover the secondary particle. The layer may be amorphous or crystalline. The layer may comprise an oxide, a phosphate, a pyrophosphate, a fluorophosphate, a carbonate, a fluoride, an oxyfluoride, or a combination thereof, of an element such as Al, Ti, B, Li, or Si, or a combination thereof. In some aspects the outer layer comprises a borate, an aluminate, a silicate, a fluoroaluminate, or a combination thereof. Optionally, the outer layer comprises a carbonate. Optionally, the outer layer comprises ZrO2, AI2O3, TiO2, AIPO4, AIF3, B2O3, SiO2, Li2O, Li2CO3, or a combination thereof. Optionally, an outer layer includes or is AIPO4 or IJ2CO3. The layer may be deposited disposed by any process or technique that does not adversely affect the desirable properties of the particle. Representative methods include spray coating and immersion coating, for example.

[0060] Also provided are electrodes that include as a component of or the sole electrochemically active material a secondary particle as described herein. A secondary particle as provided herein is optionally included as an active component of a cathode. A cathode optionally includes a secondary particle disclosed above as an active material, and may further include a conductive agent and/or a binder. The conductive agent may include any conductive agent that provides suitable properties and may be amorphous, crystalline, or a combination thereof. The conductive agent may include a carbon black, such as acetylene black or lamp black, a mesocarbon, graphite, graphene, carbon fiber, carbon nanotubes such as single wall carbon nanotubes or multiwall carbon nanotubes, or a combination thereof. The binder may be any binder that provides suitable properties and may include polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, poly(vinyl acetate), poly(vinyl butyral-co-vinyl alcohol-co vinyl acetate), poly(methylmethacrylate-co-ethyl acrylate), polyacrylonitrile, polyvinyl chloride- co-vinyl acetate, polyvinyl alcohol, poly(l-vinylpyrrolidone-co-vinyl acetate), cellulose acetate, polyvinylpyrrolidone, polyacrylate, polymethacrylate, polyolefin, polyurethane, polyvinyl ether, acrylonitrile-butadiene rubber, styrene-butadiene rubber, aciylonitrile-butadiene-styrene, tri-block polymer of sulfonated styrene/ethylene-butylene/styrene, polyethylene oxide, or a combination thereof, for example.

[0061] The cathode may be manufactured by combining the particle as described herein, the conductive agent (if present), and the binder in a suitable ratio, e.g., about 80 to about 98 weight percent of the active particle, about 1 to about 20 weight percent of the conductive agent, and about 1 to about 10 weight percent of the binder, based on a total weight of the particle, the conductive agent, and the binder combined. The particle, the conductive agent, and the binder may be suspended in a suitable solvent, such as N-methylpyrrolidinone, and disposed on a suitable substrate, such as aluminum foil, and dried in air. It is noted that the substrate and the solvent are presented for illustrative purposes alone. Other suitable substrates and solvents may be used or combined to form a cathode. [0062] A cathode as provided herein when cycled with a MCMB 10-28 graphite anode, a polyolefin separator and an electrolyte of 1 M LiPFe in 1/1/1 (vol.) EC/DMC/EMC with 1 wt. % VC in a 2025 coin cell optionally demonstrates a significantly reduced capacity fade relative to similar Mn-rich materials with no grain boundary enrichment. The capacity measurement plotted against cycle number results in a curve with a defined slope. The capacity slope is lower when active particle material with high Mn (e.g. 30-70 at% Mn) as described herein has grain boundaries enriched with one or more enrichment elements, optionally Co and/or Al, as described herein relative to particles without such enrichment of grain boundaries. In some aspects, the capacity fade of cells is at or less than 10% for the first 200 cycles, optionally 5% or less over the first 100 cycles.

[0063] Also provided are electrochemical cells that employ an electrochemically active cathode material as provided herein as an active material in a cathode and paired to an appropriate anode. An electrochemical cell as provided herein optionally uses the electrochemically active material particles as provided herein in a cathode optionally having an initial discharge capacity of equal to or greater than about 110 mAh/g, optionally about 120 mAh/g, optionally about 130 mAh/g, optionally about 140 mAh/g, optionally about 150 mAh/g, optionally about 160 mAh/g, optionally about 170 mAh/g, optionally about 180 mAh/g, optionally about 190 mAh/g, optionally about 200 mAh/g, optionally about 210 mAh/g, optionally about 220 mAh/g, optionally about 230 mAh/g, optionally about 240 mAh/g, optionally about 250 mAh/g and optionally demonstrating capacity fade of cells is at or less than 10% for the first 200 cycles, optionally 5% or less over the first 100 cycles. In some aspects, the capacity fade of cells is at or less than 15% for the first 400 cycles, optionally 5% or less over the first 200 cycles. Optionally, the capacity fade of cells is at or less than 10% over the first 200 cycles, optionally less than 9%, optionally less than 8%, optionally less than 7%, optionally less than 6%, optionally less than 5%, optionally less than 4%, optionally less than 3%, optionally less than 2%, over the first 200 cycles. Optionally, the capacity fade of cells is at or less than 15% over the first 300 cycles, optionally less than 14%, optionally less than 13%, optionally less than 12%, optionally less than 11%, optionally less than 10%, optionally less than 9%, optionally less than 8%, optionally less than 7%, optionally less than 6%, optionally less than 5%, optionally less than 4%, optionally less than 3%, over the first 300 cycles. Optionally, the capacity fade of cells is at or less than 20% over the first 400 cycles, optionally less than 19%, optionally less than 18%, optionally less than 17%, optionally less than 16%, optionally less than 15%, optionally less than 14%, optionally less than 13%, optionally less than 12%, optionally less than 11%, optionally less than 10%, optionally less than 9%, optionally less than 8%, optionally less than 7%, optionally less than 6%, optionally less than 5%, optionally less than 4%, optionally less than 3%, over the first 400 cycles.

[0064] The electrochemical cell may be a lithium-ion cell, a lithium-polymer cell, or a lithium cell, for example. The cell may include a cathode, an anode, and a separator interposed between the cathode and the anode. A battery may include 1 cell or 2 or more cells.

[0065] The separator may be a microporous membrane, and may include a porous film including polypropylene, polyethylene, or a combination thereof, or may be a woven or non-woven material such a glass-fiber mat. Certain other separators as known in the art may also be used.

[0066] The anode may include a coating on a current collector. The coating may include a suitable carbon, such as graphite, coke, a hard carbon, or a mesocarbon such as a mesocarbon microbead, for example. The current collector may be copper foil, for example.

[0067] In other aspects, an anode active material may be an oxide of titanium optionally including a nanowire such as TiCh-B nanowires as described by Armstrong, et al., Journal of Power Sources, 146, no. 1-2 (2005): 501-506. One illustrative example of an oxide of titanium is a lithium titanium oxide (LTO). The lithium titanium oxide may have a spinel type structure. An anode may include an anode electrochemically active material optionally of the formula Li₄₊aTi₅0i2₊b (IV) wherein -0.3<a<3.3, -0.3<b<0.3. In some aspects the lithium titanium oxide may be of the formula III

Li4_+yTi₅0i2, (III) wherein, 0<y<3, 0.1<y<2.8, or 0<y<2.6.

Alternatively, the lithium titanium oxide may be of Formula IV.

Li3+zTie-zOi2, (IV)

[0068] where in formula IV, 0<z<l. Optionally 0<z<l, 0.1<z<0.8, or 0<z<0.5. A combination of anode electrochemically active materials including at least one of the foregoing lithium titanium oxides may be used. In some aspects an anode electrochemically active material includes or is Li^isOn.

[0069] The anode current collector or the cathode current collector may be formed of Ti, Al, Cu, or the like for example. A current collector may be in the form of a foil, a perforated foil, a screen, or other suitable configuration. A current collector for a cathode may be in electrical contact with a cathode active material as provided herein. A current collector for an anode may be in electrical contact with an anode active materials provided herein.

[0070] The electrochemical cell also includes an electrolyte that may contact the positive electrode (cathode), the negative electrode (anode), and the separator. The electrolyte may include an organic solvent and a lithium salt. The organic solvent may be a linear or cyclic carbonate. Representative organic solvents include ethylene carbonate (EC), propylene carbonate, butylene carbonate, trifluoropropylene carbonate, y-butyrolactone, sulfolane, 1,2-dimethoxy ethane, 1,2- di ethoxy ethane, tetrahydrofuran, 3-methyl-l,3-dioxolane, methyl acetate, ethyl acetate, methylpropionate, ethylpropionate, dimethyl carbonate (DMC), diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, methylpropyl carbonate, propane sultone, or a combination thereof. In another aspect the electrolyte is a polymer electrolyte.

[0071] Optionally, an electrolyte an electrolyte excludes ethylene carbonate. Optionally, an electrolyte includes DMC and one or more other additives or co-solvents and excludes EC. Optionally, an electrolyte includes DMC and two additives, optionally three additives, optionally four additives, optionally 5 additives. Optionally, an electrolyte includes DMC, LiPFe, and two additional additives, optionally three additional additives, optionally four additional additives, optionally 5 additional additives.

[0072] Further, the select additives in an electrolyte used in a battery as provided herein are less toxic than organic sulfate and sultone type additives. Illustrative examples of such additives include but are not limited to fluoroethylene carbonate (FEC), difluoroethylene carbonate (F2EC), tris(trimethylsilyl)malonate (TMSM), tris(trimethylsilyl)phosphite (TMSPi), tris(trimethylsilyl)phosphate (TMSPO4), lithium bis(oxalato)borate (LiDFOB), and the co-solvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some aspects, additives optionally include combinations of fluoroethylene carbonate, difluoroethylene carbonate, and lithium difluoro(oxalato)borate. [0073] An additive is optionally present in an electrolyte at less than 5 weight percent (wt%) depending on the additive. Optionally, an additive is present at less than or equal to 5 wt%, optionally 4.5 wt%, optionally 4 wt%, optionally 3.5 wt%, optionally 3 wt%, optionally 2.5 wt%, optionally 2 wt%, optionally 1.5 wt%, optionally 1 wt%, optionally 0.5 wt%, optionally 0.1 wt%. [0074] In some aspects, an additive in an electrolyte is optionally present at more than 0.1 wt%, optionally 0.5 wt%, optionally more than 1 wt%, optionally more than 1.5 wt%, optionally more than 2 wt%, optionally more than 2.5 wt%, optionally more than 3 wt%, optionally more than 3.5 wt%, optionally more than 4 wt%, optionally more than 4.5 wt%, optionally more than 5 wt%.

[0075] Optionally, an electrolyte includes DMC and FEC wherein the FEC is present at more than 0.1 wt%, optionally 0.5 wt%, optionally more than 1 wt%, optionally more than 1.5 wt%, optionally more than 2 wt%, optionally more than 2.5 wt%, optionally more than 3 wt%, optionally more than 3.5 wt%, optionally more than 4 wt%, optionally more than 4.5 wt%, optionally more than 5 wt%, optionally more than 6 wt%. In some aspects, the range of FEC is from 1.5 wt% to 6 wt%, optionally from 2 wt% to 5 wt%.

[0076] Optionally, an electrolyte includes DMC and F2EC wherein the F2EC is present at more than 0.1 wt%, optionally 0.5 wt%, optionally more than 1 wt%, optionally more than 1.5 wt%, optionally more than 2 wt%, optionally more than 2.5 wt%, optionally more than 3 wt%, optionally more than 3.5 wt%, optionally more than 4 wt%, optionally more than 4.5 wt%, optionally more than 5 wt%. In some aspects, the range of F2EC is from 1.5 wt% to 6 wt%, optionally from 2 wt% to 5 wt%.

[0077] In some aspects, an electrolyte includes DMC and TMSPO4 wherein the TMSPO4 is present less than 5 weight percent (wt%). Optionally, TMSPO4 is present at less than or equal to 5 wt%, optionally 4.5 wt%, optionally 4 wt%, optionally 3.5 wt%, optionally 3 wt%, optionally 2.5 wt%, optionally 2 wt%, optionally 1.5 wt%, optionally 1 wt%, optionally 0.5 wt%, optionally 0.1 wt%. In some aspects, the range of TMSPO4 is from 0.1 wt% to 3 wt%, optionally from 0.5 wt% to 2 wt%.

[0078] In some aspects, an electrolyte includes DMC and TMSM wherein the TMSM is present less than 5 weight percent (wt%). Optionally, TMSM is present at less than or equal to 5 wt%, optionally 4.5 wt%, optionally 4 wt%, optionally 3.5 wt%, optionally 3 wt%, optionally 2.5 wt%, optionally 2 wt%, optionally 1.5 wt%, optionally 1 wt%, optionally 0.5 wt%, optionally 0.1 wt%. In some aspects, the range of TMSM is from 0.1 wt% to 3 wt%, optionally from 0.5 wt% to 2 wt%.

[0079] In some aspects, an electrolyte includes DMC and TMSPi wherein the TMSPi is present less than 5 weight percent (wt%). Optionally, TMSPi is present at less than or equal to 5 wt%, optionally 4.5 wt%, optionally 4 wt%, optionally 3.5 wt%, optionally 3 wt%, optionally 2.5 wt%, optionally 2 wt%, optionally 1.5 wt%, optionally 1 wt%, optionally 0.5 wt%, optionally 0.1 wt%. In some aspects, the range of TMSPi is from 0.1 wt% to 3 wt%, optionally from 0.5 wt% to 2 wt%.

[0080] In some aspects, an electrolyte includes DMC and the co-solvent TFETFPE wherein the TFETFPE is present less than 20 weight percent (wt%) depending on the additive. Optionally, the TFETFOE is present at less than or equal to 15 wt%, optionally 10 wt%. In some aspects, the TFETFPE is present at 1 wt% to 20 wt% or any value or range therebetween, optionally 2 wt% to 10 wt%.

[0081] Representative lithium salts useful in an electrolyte include but are not limited to LiPFe, LiBF₄, LiAsFe, LiClO₄, LiCF₃SO₃, Li(CF₃SO₂)2N, LiN(SO2C₂F₅)2, LiSbFe, LiC(CF₃SO₂)3, LiC₄F9SO₃, and LiAlCl₄. The lithium salt is optionally present in the electrolyte at a concentration equal to or greater than 0.1 molar (M), optionally 0.5 M, optionally 0.6 M, optionally 0.7 M, optionally 0.8 M, optionally 0.9 M, optionally 1 M, optionally 1.1 M, optionally 1.2 M, optionally 1.3 M, optionally 1.4 M optionally 1.5 M, optionally 1.6 M, optionally 1.7 M, optionally 1.8 M, optionally 1.9 M, optionally 2.0 M. The lithium salt may be dissolved in the organic solvent. A combination comprising at least one of the foregoing can be used. The concentration of the lithium salt can be 0.1 to 2.0M in the electrolyte.

[0082] The concentration of lithium salt when present is optionally equal to or greater than 1.0 M, optionally at or greater than 1.3 M or 2.0 M. With certain additives, for example fluoroethylene carbonate and lithium difluoro(oxalato)borate, the higher concentration of lithium salt, for example 2 M lithium salt, improves cycle life relative to 1.3 M LiPFe present in the electrolyte.

[0083] The electrolyte may be a solid ceramic electrolyte. [0084] When cycling a cell or batery including an electrolyte as provided herein at about 2.5 V to greater than or equal to about 4.3 V, optionally about 2.5 V to about 4.65 V, optionally greater than about 4.3 V, a cell optionally has a capacity retention at 100 cycles of greater than or equal to about 60% relative to a first capacity. In some aspects, the capacity retention at 100 cycles is equal to or greater than or equal to 65%, optionally 66%, optionally 67%, optionally 68%, optionally 69%, optionally 70%, optionally 71%, optionally 72%, optionally 73%, optionally 74%, optionally 75%, optionally 76%, optionally 77%, optionally 78%, optionally 79%, optionally 80%, optionally 81%, optionally 82%, optionally 83%, optionally 84%, optionally 85%, optionally 86%, optionally 87%, optionally 88%, optionally 89%, optionally 90%. In any of the foregoing, an electrolyte optionally does not undergo a shuttling reaction.

[0085] In some aspects of any of the foregoing the electrochemical cell including the anode, cathode, and electrolyte as provided herein has a formation voltage (FV) of greater than about 4.3 V. In some aspects of any of the foregoing the electrochemical cell including the anode, cathode, and electrolyte as provided herein has a charge voltage (CV) of greater than about 4.3 V.

[0086] The electrochemical cell may have any suitable configuration or shape, and may be cylindrical or prismatic.

[0087] Various aspects of the present disclosure are illustrated by the following non-limiting examples. The examples are for illustrative purposes and are not a limitation on any practice of the present invention. It will be understood that variations and modifications can be made without departing from the spirit and scope of the invention.

EXAMPLES

Example 1:

Comparison Example 1:

[0088] Lithium Iron Phosphate LiFePCL cathode was purchased (Targray) and tested as received.

Example 2:

Comparison Example 2: Preparation of high-Mn Li1.2Ni0.40Mn0.56Co0.04O2 cathode.

[0089] A precursor material having the composition of Nio.4oMno.56Coo.o4(OH)2 was made by first dissolving 4.2kg NiSO4 • 6H2O, 449g CoSO4 • 7H2O, and 3.7kg of MnSO4 • 7H2O (all available from Barentz) into 17.2 liters of DI water, creating a 2M mixed-metal nitrate solution. To a 3L reaction vessel, a charge solution containing 1.8L DI water, 180 g NaSO4 (Barentz), and 30 ml NH3OH (14 M) (Barentz) was added and stirred until a temperature of 60°C was reached. At this point, the metal nitrate solution was added to the reactor (~4ml/min) along with NH3OH (14M, ~0.2ml/min) and NaOH (10M, ~2ml/min). The solution was stirred at 900rpm using an over-head stirrer and the pH was maintained at -11.4 and NH3OH = 0.3 IM throughout the reaction. Product slurry containing Nio.4oMno.56Coo.o4(OH)2 was continuously pumped out of the 3L reactor to keep the reactor volume constant. The solution was filtered, placed into an alumina crucible, and dried at 120°C overnight.

[0090] For the synthesis of high-Mn layered cathode Li1.2Ni0.40Mn0.56Co0.04O2, 22.23 g of LiOH (dehydrated and milled) and 71.13g of Nio.4oMno.56Coo.o4(OH)2 (made in-house) were added to a 500ml jar and shaken. The mixture was placed into an alumina crucible and sintered. Sintering was performed by heating at a rate of about 5° C. per minutes to about 450° C. and held at 450° C. for about two hours. The temperature was then raised at about 2°C to about 850° C, and held for about twelve hours with oxygen purge. The sample was then allowed to cool naturally. The cooled sample was sieved providing the Li1.15Ni0.40Mn0.56Co0.04O2. The resulting sample was sieved before being tested in coin cells.

Example 2: Preparation of high-Mn Li1.2Ni0.40Mn0.56Co0.04O2 cathode with Co and Al-enriched Grain Boundaries.

[0091] 2.43 grams (g) Co(NCh)2 • 6H2O cobalt nitrate, 0.5g aluminum nitrate A1(NO3)3« 9H2O, and 0.83g LiNOi were dissolved in 20 ml of methanol (in a flat bottom flask with magnetic stir bar) heated to 40° C, and 20 g of the Li1.2Ni0.40Mn0.56Co0.04O2 of comparative example 2 was added thereto. The Flask was attached to a rotary evaporator with water bath at 40°C-50°C. Vacuum was applied to the sample, removing the methanol. The resulting dried powder was placed into an alumina crucible and heated at a rate of 5 °C. per minute to about 450 °C., and held at about 450 °C. for about one hour. The temperature was then raised at about 2 °C per minute to about 700 °C, and held for about two hours. The sample was then allowed to cool naturally to room temperature to provide a material having the overall composition Li1.2Ni0.38Mn0.53Co0.08Al0.01O2.

[0092] Cathode electrodes with 94:3 :3 formulation (active:AB100:PVDF) of the Example 2 and Comparison Examples 1 and 2 materials were assembled in lithium-ion coin cells (size 2025) opposite graphitic carbon anodes (MCMB 10-28, MSE Supplies) with a microporous polyolefin separator (Celgard 2325) and electrolyte of 1 M LiPFe in 1/1/1 (vol.) EC/DMC/EMC with 1 wt. % VC (Kishida Chemical). These lithium-ion cells underwent extended 1C charge, 1C discharge cycling between 4.2 V and 2.7 V at 45°C. FIG. 2 illustrates the results of this 1C/1C cycling. As illustrated by FIG. 2A, the LFP cathode of Comparative Example 1 showed rapid specific energy fade, whereas the high Mn and Co grain boundary enriched material of Example 2 showed excellent first cycle specific energy and less than 10% fade in specific energy out to 300 cycles. As illustrated in FIG. 2B, the Mn-rich material of Comparative example 2 showed relatively rapid capacity fade. The grain boundary enriched high Mn material of Example, 2, however, showed excellent capacity retention. Discharge capacities at various rates for the same electrodes electrochemically tested in half cells (cycled between 2.7 - 4.8V at room temperature) opposite Li metal for materials in Example 2 and Comparative Example 2 are illustrated in Table 2.

[0093] Table 2 : Half-cell rate capacity test Comparison Example 2 and Example 2. Cells cycled between 2.8-4.8V at room temperature with Li anode. * cells cycled between 2.8 - 4.3V.

Example 3

Comparison Example 3: Preparation of Li1.2Ni0.40Mn0.56Co0.04O2

[0094] A material having an overall composition of Li12Ni040Mn056Co004O2 was prepared using the same method as provided in Comparison Example 2 except this sample was calcined at 900 °C.

Example 3: Preparation of Li1.2Ni0.40Mn0.56Co0.04O2 with Co and Al-enriched Grain Boundaries. [0095] A material having an overall composition of Li1.2Ni0.38Mn0.53Co0.08Al0.01O2 was prepared in the same manner as Example 2 except this sample was made with the product produced in Comparison Example 3.

[0096] The materials of example 3 were analyzed by X-ray diffraction (XRD). Results are illustrated in FIG. 3. As illustrated in FIG. 3, XRD peaks are consistent with a rhombohedral LiM02 structure with R-3M space group. Inset: shows expanded XRD pattern between 20° - 27° 2Q showing a Li2MnOs monoclinic structure consistent with high-Mn cathodes. (Haijun Yu & Haoshen Zhou, J Phys Chem Let, 2013; 4: 1268-1280).

[0097] Cathode electrodes with the materials of Example 3 and Comparative Example 3 where assembled into Li-anode half cells which were cycled between 2.8-4.8V at room temperature. Results are illustrated in Table 3. Cells were also constructed into full cells with graphite anode.

[0098] Table 3 : Half-cell rate capacity test Comparison Example 3 and Example 3. Cells cycled between 2.8-4.8V at room temperature with Li anode.

Example 4

Comparison Example 4: Preparation of Li1.2Ni0.40Mn0.56Co0.04O2

[0099] A material having an overall composition of Nio.4oMno.56Coo.o4(OH)2 was prepared using the same method as provided in Comparison Example 2 except with a pH = 10.9 and NH30H= 0.31 M to increase the solubility of metals in the supernatant. Thus, creating a material similar to Comparison Example 2 but with higher tap density.

[00100] A material having an overall composition of Li1.2Ni0.40Mn0.56Co0.04O2 was prepared using the same method as provided in Comparison Example 2 except this sample was calcined at 850°C.

Example 4: Preparation of Li1.2Ni0.40Mn0.56Co0.04O2 with Co and Al-enriched Grain Boundaries [00101] A material having an overall composition of Li1.2Nio.38Mno.53Coo.osAlo.1O2 was prepared in the same manner as Example 2 except 1.52 grams (g) Co(NO3)2 • 6H2O, 0.29g A1(NO3)3 • 9H2O, and 0.23g LiNCh were mixed with 25 g of product produced Comparison Example 4.

[00102] Cathode electrodes with the materials of Comparison Example 4 and Example 4 were subjected to full coin cell build as per Example 2 except the electrolyte 1.15 M LiPFe in 3/3/4 (vol.) ECZDEC/DMC was used. In FIG. 4A cells were initially formed to 4.65V and cycled at 2.8- 4.3V on a rapid cycle test at an average 1C discharge rate. The discharge capacity of the Mn-rich materials faded rapidly whereas grain boundary enriching the high Mn material led to excellent capacity retention. FIG. 4B —cells were initially formed to 4.65V and cycled at 2.8- 4.6V or 2.8- 4.3V on a rapid cycle test at an average 1C discharge rate. The discharge capacity of this material cycled at 4.6V has a 20% increase in capacity with similar capacity retention (89% vs 91% at 350 cycles) compared to the material cycled at 4.3 V.

[00103] Cathode electrodes with the materials of Example 4 and Comparative Example 4 were assembled into Li-anode half cells which were cycled between 2.8-4.8V at room temperature. Results are illustrated in Table 4. Cells were also constructed into full cells with graphite anode.

[00104] Table 4 : Half-cell rate capacity test Comparison Example 4 and Example 4. Cells cycled between 2.8-4.8V at room temperature with Li anode.

Example 5

Comparison Example 5: Preparation of Li1.08Ni0.56Mn0.40Co0.04O2

[00105] A material having an overall composition of Nio.56Mno.4oCoo.o4(OH)2 was prepared using the same method as provided in Comparison Example 2 except the ratio of Ni/Mn was changed, the pH = 11.73 and NH3OH = 0.24 M.

[00106] A material having an overall composition of Li1.08Ni0.56Mn0.40Co004O2 was prepared using the same method as provided in Comparison Example 2 except 71.16 g Nio.56Mno.4oCoo.o4(OH)2 from comparison example 5 was mixed with 20.41 g LiOH (dried and milled).

Example 5: Preparation of Li10 Ni056Mn040Co004O2 with Co and Al-enriched Grain Boundaries [00107] A material having an overall composition of Li1.08Ni0.54Mn0.39Co0.06Al0.01O2 was prepared in the same manner as Example 2 except 1.51 grams (g) Co(NO3)2 • 6H2O cobalt nitrate, 0.62g aluminum nitrate Al(NOs)3 • 9H O, and 0.67g LiNOs were mixed with 25 g of product produced in Comparison Example 5.

[00108] Cathode electrodes prepared with materials in Comparison Example 5 and Example 5 were evaluated in full coin cells using the same procedure as in Example 2. The cells were subjected to full cell cycling in cells constructed as above and cycled at 1C charge/ 1C discharge at 45°C between 2.7 - 4.2V with graphite anode. Results are illustrated in FIG. 5. Example 6

Comparison Example 6. Preparation of Li1.03Ni0.6iMn0.35Co0.04O2

[00109] A material having an overall composition of Nio.6iMno.35Coo.o4(OH)2 was prepared using the same method as provided in Comparison Example 2 except the ratio of Ni/Mn was changed, the pH=l 1.94, and the NH3OH = 0.2 M.

[00110] A material having an overall composition of Li1.03Ni0.6iMn0.35Co004O2 was prepared using the same method as provided in Comparison Example 2 except 71.16 g Nio.6iMno.35Coo.o4(OH)2 from comparison example 6 was mixed with 19.25 g LiOH (dried and milled).

Example 6. Preparation of Li1.03Ni0.6iMn0.35Co0.04O2 with Co and Al-enriched Grain Boundaries [00111] A material having an overall composition of Li1.03Ni0.57Mn0.34Co0.08Al0.01O2 was prepared in the same manner as Example 2 except this sample was made with the product produced in Comparison Example 6.

[00112]

[00113] Cathode electrodes with the materials of Comparison Example 6 and Example 6 were subjected to full coin cell build as per Example 2 except the electrolyte 1.15 M LiPFe in 3/3/4 (vol.) EC/DEC/DMC was used. In FIG. 6 cells were initially formed to 4.65V and cycled at 2.8- 4.3V on a rapid cycle test at an average 1C discharge rate. The discharge capacity of the Mn-rich materials faded rapidly whereas grain boundary enriching the high Mn material led to excellent capacity

Example 7.

Comparison Example 7. Preparation of Li 128Ni036Mn060Co004O2

[00114] A material having an overall composition of Nio.36Mno.6oCoo.o4(OH)2 was prepared using the same method as provided in Comparison Example 2 except the ratio of Ni/Mn was changed, the pH = 10.75 and the NH3OH = 0.25.

[00115] A material having an overall composition of Li1.28Ni0.36Mn0.60Co004O2 was prepared using the same method as provided in Comparison Example 2. except 71.13 g Nio.36Mno.6oCoo.o4(OH)2 from comparison example 7 was mixed with 24.53 g LiOH (dried and milled).

Example 7. Preparation of Li1.28Ni0.36Mn0.60Co0.04O2 with Co and Al-enriched Grain Boundaries [00116] A material having an overall composition of Li1.28Ni0.35Mn0.5 Co0.06Al0.01O2 was prepared in the same manner as Example 2 except 1.51 grams (g) Co(NO3)2 • 6H2O cobalt, 0.62 g A1(NO₃)3 • 9 H2O, and 0.67 g LiNOi were mixed with 25 g of product produced in Comparison Example 7.

[00117] Cathode electrodes with the materials of Comparison Example 7 and Example 7 were subjected to full coin cell build as per Example 2 except the electrolyte 1.15 M LiPFe in 3/3/4 (vol.) EC/DEC/DMC was used. In FIG. 7 cells were initially formed to 4.65V and cycled at 2.8- 4.3V on a rapid cycle test at an average 1C discharge rate. The discharge capacity of the Mn-rich materials faded rapidly whereas grain boundary enriching the high Mn material led to excellent capacity

Example 8.

Table 5: Capacity Fade for various samples as provided in Examples 4-7.

ADDITIONAL EXEMPLARY ASPECTS

[00118] Aspect 1. An electrochemically active material comprising: a first composition of the formula Lii+aMCh+b (Formula I) where -0.3<a<1.3 and

- 0.3<b<l .3 and where M comprises 30 at% to 70 at% Mn and 25 at% to 70 at% Ni, said first composition formed of a polycrystalline morphology comprising a plurality of crystallites and a grain boundary between adjacent crystallites, said grain boundary comprising a second composition of the formula Lii+aM’Ch b (Formula II) where -0. l<a<l .3 and -0.3<b<l .3, said grain boundary comprising one or more enrichment elements in at least a portion thereof, said one or more enrichment elements present at a higher atomic percentage in said portion than in an adjacent crystallite, wherein said one or more enrichment elements is selected from the group consisting of Co, Al, and both Co and Al.

[00119] Aspect 2. The electrochemically active material of Aspect 1, wherein where M comprises 30 at% to 65 at% Mn, optionally 35 at% to 65 at% Mn.

[00120] Aspect 3. The electrochemically active material of Aspects 1 or 2, wherein said second composition has an a-NaFeCh-type structure, a cubic structure, a spinel structure, or a combination thereof.

[00121] Aspect 4. The electrochemically active material of Aspects 1-3, wherein said particle has a particle size of about 1 pm to about 25 pm.

[00122] Aspect 5. The electrochemically active material of Aspects 1-4, wherein said crystallites each independently have a particle size of less than about 1 pm.

[00123] Aspect 6. The electrochemically active material of Aspects 1-5, wherein said enrichment element comprises Co.

[00124] Aspect 7. The electrochemically active material of Aspects 1-6, wherein M further comprises Co.

[00125] Aspect 8. The electrochemically active material of Aspect 7, wherein Co is present at greater than about 0 at% to about 15 at%, optionally about 0.01 at% to about 10 at%. [00126] Aspect 9. The electrochemically active material of Aspects 7 or 8, wherein M comprises Mn at about 30 at% to about 70 at%, Ni at about 25 at% to about 70 at%, greater than 0 to about 15 at% Co, and/or 0 to about 5 at% Mg, or any combination thereof.

[00127] Aspect 10. The electrochemically active material of any one of Aspects 1-9, wherein M comprises about 30 at% to about 65 at% Mn, about 25 at% to about 70 at% Ni, greater than 0 to about 15 at% Co, and about 0 at% to about 5 at% Mg.

[00128] Aspect 11. The electrochemically active material of any one of Aspects 1-10, wherein said enrichment element is Al, or both Co and Al.

[00129] Aspect 12. The electrochemically active material of any one of Aspects 1-11, wherein Mn in said first composition is present at about 45 at% to about 65 at%.

[00130] Aspect 13. The electrochemically active material of any one of Aspects 1-12, wherein M comprises Ni at less than or equal to 40 at%.

[00131] Aspect 14. The electrochemically active material of any one of Aspects 1-13, wherein M comprises about 25 at% to about 70 at% Ni, about 0-15 at% Co, about 30 at% to about 65 at% Mn, and 0-10 at% additional elements.

[00132] Aspect 15. The electrochemically active material of any one of Aspects 1-14, wherein said grain boundary comprises said enrichment element at a higher atomic percentage than an average atomic percentage of the enrichment element in an adjacent crystallite.

[00133] Aspect 16. The electrochemically active material of Aspects 1-15, wherein M’ comprises Mn at 30 at% to 70 at% relative to the total M’.

[00134] Aspect 17. The electrochemically active material of claim 16, wherein M’ comprises Ni at about 10 atomic percent to about 70 atomic percent (at%) of total M’.

[00135] Aspect 18. An electrode, the electrode comprising the electrochemically material of any one of Aspects 1-17, and further comprising a current collector in electrical contact with said particle or plurality of particles.

[00136] Aspect 19. An electrochemical cell comprising a first electrode and a second electrode, the first electrode is the electrode of Aspect 18. [00137] Aspect 20. The electrochemical cell of Aspect 19, wherein said second electrode comprises carbon or a lithium titanate.

[00138] Aspect 21. The electrochemical cell of Aspect 20, wherein said carbon comprises graphite.

[00139] Aspect 22. The electrochemical cell of any of Aspects 19-21, characterized by a discharge capacity of greater than 140 mAh/g maintainable over 400 cycles or more, optionally greater than 160 mAh/g maintainable over 400 cycles or more, when cycled with (~2 mAh/cm² cathode loading) cycled at 45 °C from 2.7 - 4.2 V with average C-rate > 1, when said electrochemical cell comprises a graphite anode.

[00140] Aspect 23. The electrochemical cell of any of Aspects 19-21, characterized by a discharge capacity of greater than 140 mAh/g maintainable over 400 cycles or more, optionally greater than 200 mAh/g maintainable over 400 cycles or more, when cycled with (~2 mAh/cm² cathode loading) cycled at 45 °C from 2.7 - 4.6 V with average C-rate > 1, when said electrochemical cell comprises a graphite anode.

[00141] Aspect 24. An electrochemical cell comprising:

[00142] a cathode comprising an electrochemically active material of any of Aspects 1-17, an anode and an electrolyte, the electrolyte excluding ethylene carbonate.

[00143] Aspect 25. The electrochemical cell of Aspect 24, wherein said anode comprises carbon or a lithium titanate.

[00144] Aspect 26. The electrochemical cell of Aspect 25, wherein said anode comprises carbon.

[00145] Aspect 26. The electrochemical cell of any of Aspects 24-26, wherein said electrolyte comprises a lithium salt and dimethyl carbonate alone or in combination with one or more additives.

[00146] Aspect 27. The electrochemical cell of Aspect 26, wherein said additives comprise fluoroethylene carbonate (FEC), difluoroethylene carbonate (F2EC), tris(trimethylsilyl)malonate (TMSM), tris(trimethylsilyl)phosphite (TMSPi), tris(trimethylsilyl)phosphate (TMSPO4), lithium bis(oxalato)borate (LiDFOB), and the cosolvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some aspects, additives optionally include combinations of fluoroethylene carbonate, difluoroethylene carbonate, lithium difluoro(oxalato)borate, or a combination thereof.

[00147] While this disclosure describes exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the disclosed embodiments. In addition, many modifications can be made to adapt a particular situation or material to the teachings of this disclosure without departing from the scope thereof. Therefore, it is intended that this disclosure not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this disclosure. It should also be understood that the embodiments disclosed herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects of each embodiment should be considered as available for other similar features or aspects of other embodiments.

[00148] It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

[00149] It will be understood that, although the terms “first,” “second,” “third” etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, “a first element,” “component,” “region,” “layer,” or “section” discussed below could be termed a second element, component, region, layer, or section without departing from the teachings herein.

[00150] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms, including “at least one,” unless the content clearly indicates otherwise. “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. The term “or a combination thereof’ means a combination including at least one of the foregoing elements.

[00151] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[00152] All at% concentrations as provided herein are considered about the numerated concentration whether explicitly stated as such or not, optionally where “about” includes equivalents and/or values within experimental error. In some aspects as may be optionally desired, all or some of the at% concentrations are exactly the numerated values or ranges.

[00153] Various modifications of the present invention, in addition to those shown and described herein, will be apparent to those skilled in the art of the above description. Such modifications are also intended to fall within the scope of the appended claims.

[00154] It is appreciated that all reagents are obtainable by sources known in the art unless otherwise specified. Methods of nucleotide amplification, cell transfection, and protein expression and purification are similarly within the level of skill in the art.

[00155] Patents, publications, and applications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These patents, publications, and applications are incorporated herein by reference to the same extent as if each individual patent, publication, or application was specifically and individually incorporated herein by reference.

REFERENCE LIST

[00156] Y. Ikuhara, “Atomic-scale observations of (010) LiFePCh surface before and after chemical delithiation” Nano Lett. 2016, 16, 5409-5414 [00157] Haijun Yu & Haoshen Zhou, “High-Energy cathode materials (Li2MnO3-LiMO2) for lithium-ion batteries” J Phys Chem Let 2013, 4, 1268-1280

[00158] He, et al., “Challenges and recent advances in high capacity Li-Rich cathode materials for high energy density lithium ion batteries” Adv Mater. 2021, 33, 2005937

Claims

1. An electrochemically active material comprising: a first composition of the formula Lii+aMCh+b (Formula I) where -0.3<a<1.3 and 0.3<b<1.3 and where M comprises 30 at% to 70 at% Mn and 25 at% to 70 at% Ni, said first composition formed of a polycrystalline morphology comprising a plurality of crystallites and a grain boundary between adjacent crystallites; said grain boundary comprising a second composition of the formula Lii+aM’Ch+b (Formula II) where -0.1<a<1.3 and - 0.3<b<1.3; said grain boundary comprising one or more enrichment elements in at least a portion thereof, said one or more enrichment elements present at a higher atomic percentage in said portion than in an adjacent crystallite, wherein said one or more enrichment elements comprises Co, Al, or both Co and Al.

2. The electrochemically active material of claim 1, wherein where M comprises 30 at% to 65 at% Mn.

3. The electrochemically active material of claim 1, wherein said second composition has an a-NaFeCh-type structure, a cubic structure, a spinel structure, or a combination thereof.

4. The electrochemically active material of claim 1, wherein said electrochemically active material is in the form of a secondary particle with a particle size of about 1 pm to about 25 pm.

5. The electrochemically active material of claim 1, wherein said crystallites each independently have a particle size of less than about 1 pm.

6. The electrochemically active material of claim 1, wherein said enrichment element comprises Co.

7. The electrochemically active material of claim 1, wherein M further comprises Co.

8. The electrochemically active material of claim 7, wherein Co is present at greater than about 0 at% to about 15 at%, optionally about 0.01 at% to about 10 at%.

9. The electrochemically active material of claim 7, wherein M comprises Mn at about 30 at% to about 70 at%, Ni at about 25 at% to about 70 at%, greater than 0 to about 15 at% Co, and/or 0 to about 5 at% Mg, or any combination thereof.

10. The electrochemically active material of any one of claims 1-9, wherein M comprises about 30 at% to about 65 at% Mn, about 25 at% to about 70 at% Ni, greater than 0 to about 15 at% Co, and about 0 at% to about 5 at% Mg.

11. The electrochemically active material of any one of claims 1-9, wherein said enrichment element is Al, or both Co and Al.

12. The electrochemically active material of any one of claims 1-9, wherein Mn in said first composition is present at about 45 at% to about 65 at%.

13. The electrochemically active material of any one of claims 1-9, wherein M comprises Ni at less than or equal to 40 at%.

14. The electrochemically active material of any one of claims 1-9, wherein M comprises about 25 at% to about 70 at% Ni, about 0-15 at% Co, about 30 at% to about 65 at% Mn, and 0-10 at% additional elements.

15. The electrochemically active material of any one of claims 1-9, wherein said grain boundary comprises said enrichment element at a higher atomic percentage than an average atomic percentage of the enrichment element in an adjacent crystallite.

16. The electrochemically active material of claim 1, wherein M’ comprises Mn at 10 at% to 70 at% relative to the total M’, optionally 30 at% to 65 at% relative to the total M’.

17. The electrochemically active material of claim 15, wherein M’ comprises Ni at about 10 atomic percent to about 70 atomic percent (at%) of total M’.

18. An electrode, the electrode comprising the electrochemically active material of any one of claims 1-9, and further comprising a current collector in electrical contact with said electrochemically active material.

19. An electrochemical cell comprising a first electrode and a second electrode, the first electrode is the electrode of claim 18.

20. The electrochemical cell of claim 19, wherein said second electrode comprises carbon or a lithium titanate.

21. The electrochemical cell of claim 20, wherein said carbon comprises graphite.

22. The electrochemical cell of claim 19, characterized by a discharge capacity of greater than 140 mAh/g maintainable over 400 cycles or more, optionally greater than 160 mAh/g maintainable over 400 cycles or more, when cycled with (~2 mAh/cm² cathode loading) cycled at 45 °C from 2.7 - 4.2 V with average C-rate > 1, when said electrochemical cell comprises a graphite anode.

23. The electrochemical cell of claim 19, characterized by a discharge capacity of greater than 140 mAh/g maintainable over 400 cycles or more, optionally greater than 200 mAh/g maintainable over 400 cycles or more, when cycled with (~2 mAh/cm² cathode loading) cycled at 45 °C from 2.7 - 4.6 V with average C-rate > 1, when said electrochemical cell comprises a graphite anode.

24. An electrochemical cell comprising: a cathode comprising an electrochemically active material of any of claims 1-9, an anode and an electrolyte, the electrolyte excluding ethylene carbonate.

25. The electrochemical cell of claim 24, wherein said anode comprises carbon or a lithium titanate.

26. The electrochemical cell of claim 25, wherein said anode comprises carbon.

27. The electrochemical cell of claim 24, wherein said electrolyte comprises a lithium salt and dimethyl carbonate alone or in combination with one or more additives.

28. The electrochemical cell of claim 27, wherein said additives are fluoroethylene carbonate (FEC), difluoroethylene carbonate (F2EC), tris(trimethylsilyl)malonate (TMSM), tris(trimethylsilyl)phosphite (TMSPi), tris(trimethylsilyl)phosphate (TMSPO4), lithium bis(oxalato)borate (LiDFOB), and the co-solvent 1, 1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some aspects, additives optionally include combinations of fluoroethylene carbonate, difluoroethylene carbonate, lithium difluoro(oxalato)borate, or a combination thereof.

29. An electrochemical cell comprising a cathode comprising an electrochemically active material as provided herein, an anode, and an electrolyte as described herein.

30. An electrochemically active material as provided herein.