High-energy, long-cycle-life cathode material and cell using the same

Abstract

The present invention provides an electrochemical active material, a cathode or electrochemical cell containing an electrochemical active material, and a method for producing an electrochemical substance. The electrochemical substance provided herein is of the formula Li 1+a MO 2+b The composition comprises a first composition of formula (I) [wherein -0.3 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3, and M comprises 30 at% to 70 at% Mn and 25 at% to 70 at% Ni], the first composition being formed from a polycrystalline form including a plurality of crystallites and grain boundaries between adjacent crystallites, the grain boundaries being of formula Li 1+a M'O 2+b The composition comprises a second composition of formula (II) [wherein -0.1 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3], wherein the grain boundaries contain at least one enriching element in at least a portion thereof, the one or more enriching elements are present in the portion with a higher atomic percentage than adjacent crystallites, and the one or more enriching elements are Co, Al, or both Co and Al.

Description

[Technical Field]

[0001] Cross-reference of related applications This application relies on and claims priority to U.S. Provisional Application No. 63 / 522,514 filed on 22 June 2023, U.S. Provisional Application No. 63 / 550,394 filed on 6 February 2024, and U.S. Provisional Application No. 63 / 647199 filed on 14 May 2024, and the entire contents of each of them are incorporated herein by reference.

[0002] field Disclosed are a polycrystalline metal oxide having improved cycle life and excellent specific energy, a method for producing the same, and articles containing the same.

[0003] background The majority of current lithium-ion batteries contain one of two main types of cathode materials. The first is a layered metal oxide with a rhombohedral layered α-NaFeO2 type structure (R-3M space group) having the general formula LiMO2 (where M is usually a combination of Ni, Co, Mn, and Al). These cathodes contain high proportions of Ni stabilized with Co and small amounts of other elements to achieve high capacity. Unfortunately, both Ni and Co are expensive, and the latter also presents environmental and supply issues. The second is olivine-type lithium iron phosphate (LFP) material. LFP materials have an orthorhombic structure with a Pmma space group (Y. Ikuhara, Nano Lett, 2016; 16: 5409-5414). LFP cathodes are considerably cheaper than LMO2 cathodes, but they also have significantly lower capacities (around 150 mAh / g compared to over 200 mAh / g for LMO2 cathodes) and below-average discharge voltages (3.4V Li-ratio compared to 3.8V for LMO2 cathodes). Importantly, because iron is extremely harmful to layered metal oxide cathodes, these two types of cathodes cannot be manufactured in the same factory environment, making it difficult for cathode suppliers currently producing LMO2 cathode materials to also produce LFP cathodes without incurring significant costs.

[0004] Thus, there is a need for a new cathode material that can achieve both high capacity retention and low cost, and can be manufactured using existing lithium-ion cathode equipment.

[0005] overview The following summary is provided to facilitate understanding of some of the innovative features unique to this disclosure and is not intended to be a complete description. A complete understanding of the various aspects of this disclosure can be obtained by considering the entire specification, claims, drawings, and abstract as a whole.

[0006] It is an electrochemical active material, with formula Li 1+a MO 2+b The composition comprises a first composition of formula (I) [wherein -0.3 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3, and M comprises 30 at% to 70 at% Mn and 25 at% to 70 at% Ni], wherein the first composition is formed from a polycrystalline form including a plurality of crystallites and grain boundaries between adjacent crystallites, and the grain boundaries are of formula Li 1+a M'O 2+bAn electrochemical active material is provided comprising a second composition of formula (II) [wherein -0.1 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3], wherein the grain boundaries contain one or more enriching elements in at least a portion thereof, one or more enriching elements are present in the portion at a higher atomic percentage than adjacent crystallites, and one or more enriching elements are selected from the group comprising or consisting of Co, Al, and both Co and Al. Optionally, M contains 30 at% to 65 at% of Mn. In some embodiments, the second composition has an α-NaFeO2 type structure, a cubic structure, a spinel structure, or a combination thereof. Optionally, the particles have a particle size of about 1 μm to about 25 μm. Optionally, the crystallites each independently have a particle size of less than about 1 μm. In any embodiment, M optionally contains Co in amounts of more than about 0 at% to about 15 at%, and optionally about 0.01 at% to about 10 at%. Optionally, M comprises about 30 at% to about 70 at% Mn, about 25 at% to about 70 at% Ni, greater than 0 to about 15 at% Co and / or 0 to about 5 at% Mg, or any combination thereof. In other embodiments, 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. In any embodiment, the enrichment is optionally Co, Al, or both Co and Al. Optionally, Mn in the first composition is present at about 45 at% to about 65 at%. Optionally, M contains 40 at% or less Ni. In some embodiments, M comprises about 25 at% to about 70 at% Ni, about 0 to 15 at% Co, about 30 at% to about 65 at% Mn and 0 to 10 at% of additional elements. In any embodiment, the grain boundaries optionally contain enriched elements at an atomic percentage higher than the average atomic percentage of enriched elements in adjacent crystallites. Optionally, M' contains 30 at% to 70 at% Mn relative to the total M'. Optionally, M' contains about 10 atomic percent to about 70 atomic percent (at%) Ni relative to the total M'. Electrochemical active materials of any embodiment provided herein, electrodes comprising a current collector electrically in contact with the electrochemical active material are also provided. Electrochemical cells are also provided, comprising a first electrode which is an electrode according to any embodiment provided herein, and a second electrode.Optionally, in an electrochemical cell, the second electrode comprises carbon or lithium titanate, and optionally, the carbon is graphite or comprises graphite. The electrochemical cells provided herein optionally, if the electrochemical cell comprises a graphite anode, (approximately 2 mAh / cm²). 2 The electrochemical cells provided herein are characterized by a discharge capacity of over 140 mAh / g, which can be maintained for more than 400 cycles, and optionally over 160 mAh / g, which can be maintained for more than 400 cycles, when cycled using a cathode load at 45°C, 2.7–4.2V, and an average C rate > 1. The electrochemical cells provided herein optionally include a graphite anode, which has a discharge capacity of (approximately 2 mAh / cm²). 2 The discharge capacity is characterized by a discharge capacity of more than 140 mAh / g, and optionally more than 200 mAh / g, that can be maintained for more than 400 cycles, when cycled using a cathode load at 45°C, 2.7–4.6V, and an average C rate > 1. In the electrochemical cell, the electrolyte does not have to contain ethylene carbonate. Optionally, the electrolyte contains lithium salts and dimethyl carbonate alone or in combination with one or more additives. Optionally, additives in the electrolyte 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 cosolvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some embodiments, the additives optionally include fluoroethylene carbonate, difluoroethylene carbonate, lithium difluoro(oxalato) borate, or combinations thereof.

[0007] The embodiments shown in the drawings are illustrative and representative in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the exemplary embodiments can be understood in conjunction with the following drawings. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a polycrystalline particle having grain boundaries, as described according to some aspects of this specification. [Figure 2A] This figure shows the data for comparing the full cell cycles of Comparative Example 1 and Example 2. The cells were cycled using a graphite anode at 45°C and 2.7~4.2V with 1C charge / 1C discharge. [Figure 2B] This figure shows the data for comparing the full cell cycles of Comparative Example 2 and Example 2. The cells were cycled using a graphite anode at 45°C and 2.7~4.2V with 1C charge / 1C discharge. [Figure 3] This figure shows the XRD diffraction pattern of Comparative Example 3. The peaks are consistent with the rhombohedral LiMO2 structure having an R-3M space group. The inset shows the enlarged XRD pattern at 20°~27°2θ, which shows a Li2MnO3 monoclinic structure consistent with a high Mn cathode. [Figure 4A] This figure shows the full coin cell cycles for Comparative Example 4 and Example 4. The cells were formed up to 4.65V and cycled at 2.8-4.3V and 45°C in a rapid cycle test with an average discharge of 1C using a graphite anode. [Figure 4B] This figure shows the full coin cell cycle of Example 4. The cell was formed up to 4.65V and cycled at 2.8–4.6V or 2.8–4.3V at 45°C in a rapid cycle test with an average discharge of 1C using a graphite anode. [Figure 5] This figure shows the data for comparing the full cell cycles of Comparative Example 5 and Example 5. The cells were formed up to 4.65V and cycled at 2.8~4.3V and 45°C in a rapid cycle test with an average discharge of 1C using a graphite anode. [Figure 6]This figure shows the data for comparing the full cell cycles of Comparative Example 6 and Example 6. The cells were formed up to 4.65V and cycled from 2.8 to 4.3V in a rapid cycle test with an average discharge of 1C using a graphite anode. [Figure 7] This figure shows the data for comparing the full cell cycles of Comparative Example 7 and Example 7. The cells were formed up to 4.65V and cycled from 2.8 to 4.3V in a rapid cycle test with an average discharge of 1C using a graphite anode.

[0009] Detailed explanation High-Mn electrochemical active materials are provided that can be used as active substances in cathodes. It has been found that the capacity degradation and / or rate capacity problems of conventional Mn-rich cathode materials can be addressed by enriching the grain boundaries with Co and combining this enrichment with a controlled amount of Mn that is significantly higher than the amount typically used in Mn-containing cathode materials. These grain boundary-enriched Mn-containing electrochemical active materials are equivalent to currently commercially available LFP cathodes but have a significant advantage over LFPs in that they are easier to manufacture using existing LMO2 electrode manufacturing facilities. The Mn-rich materials provided herein are of great interest due to their relatively low cost (reduction in the use of Co and Ni), environmental compatibility, and high thermal stability. The materials provided herein exhibit improved rate capacity and / or resistance to voltage degradation.

[0010] Furthermore, an electrochemical cell comprising an anode, an electrolyte, and a cathode is provided, optionally a secondary cell, optionally a lithium-ion secondary cell, wherein the cathode comprises an electrochemically active cathode active material comprising a plurality of particles, the plurality of particles comprising a plurality of crystallites each comprising a first composition comprising lithium, manganese, and oxygen, the grain boundaries between adjacent crystallites of the plurality of crystallites optionally comprising a second composition having a layered α-NaFeO2 type structure, a cubic structure, a spinel structure, or a combination thereof, and a combination of a controlled amount of Mn and grain boundary enrichment with one or more enriching elements achieves excellent cycle lifetime and / or rate capacity.

[0011] LiMO-type materials, in which M is one or more single metals or further containing one or more additional elements, are dense polycrystalline aggregates of primary crystals (crystallites). These LiMO-type materials are typically produced using standard solid-phase processes at temperatures in the range of 600°C to 900°C, starting from various precursor materials. Precursor materials are typically transition metal hydroxides (represented by the general formula M(OH)2), lithium precursors (e.g., LiOH or Li2CO3), or inorganic precursors of other dopants (e.g., hydroxides, carbonates, nitrates). During heating of precursor mixtures containing high-Mn-content precursor materials, polycrystalline LiMO2 and Li2MnO3 are formed, typically with the emission of gases such as H2O, CO2, or NO2.

[0012] Under appropriate conditions and using a suitable precursor, sintering results in the formation of one or more secondary particles containing multiple primary crystallites, which collectively form larger secondary particles capable of functioning as electrochemical active material. It has been previously found that grain boundaries, the regions between these primary crystallites, may be selectively enriched with Co, as described in U.S. Patent No. 9,209,455. In this disclosure, it has been found that significant further improvements can be achieved by replacing some of the elements in the bulk material with relatively high but controlled levels of Mn. Unexpectedly, combining the levels of Mn used in this disclosure with grain boundary enrichment by Co, Al, or other enriching elements described herein improves cycle life and power capability, addressing the shortcomings of conventional Mn-rich materials. While not limited to any particular theory, it is understood that the synergistic relationship between grain boundary enrichment and controlled amounts of Mn contributes to the unique benefits of the materials provided herein.

[0013] Accordingly, this disclosure provides improved electrochemical active materials that improve cycle life and / or rate capacity compared to conventional high-Mn-rich materials, such as those suitable for use as cathodes for Li-ion secondary cells. Furthermore, various methods for achieving cathode active materials and electrochemical cells using such materials as electrodes are also provided.

[0014] As used herein, “active material” is a substance that can or participates in the electrochemical charging / discharging reaction of an electrochemical cell by means of absorption or desorption of lithium, etc.

[0015] As used herein, “absorb” may mean an intercalation, insertion, or conversion alloying reaction between lithium and an active material.

[0016] As used herein, “deintercalation” may mean a deintercalation, deinsertion, or conversion dealloying reaction between lithium and an active material.

[0017] As used herein, in the context of a Li-ion cell, cathode means positive electrode and anode means negative electrode.

[0018] As shown in Figure 1, a particle is disclosed comprising a crystallite 10 containing a first composition and grain boundaries 20, 21 containing a second composition, wherein the concentration of one or more enriching elements in the grain boundaries, optionally Co, Al, or both, is higher than the concentration of those enriching elements in the crystallite. The particle comprises multiple crystallites and is referred to as a secondary particle. Optionally, a layer 30 can be placed on the outer surface of the secondary particle to obtain a coated secondary particle.

[0019] The polycrystalline lithium metal oxides provided herein exhibit improved electrochemical performance and rate capacity. These compositions prevent the rapid capacity degradation of conventional electrochemically cycled Mn-rich materials and exhibit further improved cycle life compared to LFP cathodes, while maintaining other desirable end-use article properties. Such grain boundary-enriched high-Mn materials can be readily produced by calcining a green formulation containing LiOH and a hydroxide or carbonate precursor containing Mn and Ni to form particles with distinct grain boundaries, and then enriching the grain boundaries with one or more enriching elements, such as Co or a combination of Co and Al, as an exemplary example. The resulting particles have more enriching elements that enrich the grain boundaries than before enrichment, and optionally more than within crystallites where the outer surface is in contact with the grain boundary edges in secondary particles.

[0020] Thus, compositions, systems, and methods are provided for preparing and using polycrystalline lithium-ionized high-Mn metal oxides having enriched grain boundaries as a means of achieving high initial discharge capacity and low capacity degradation during electrochemical cell cycling by using the metal oxides provided herein as the active component of the cathode, thereby overcoming the conventional problems in high-Mn formulations.

[0021] The materials provided herein include particles, each containing multiple crystallites, each comprising a first composition. These particles, formed from multiple crystallites, are sometimes referred to as secondary particles. The particles provided herein are uniquely prepared to have grain boundaries between primary crystallites. By selectively enriching these grain boundaries after their formation with, for example, Co or Al, particles are obtained that improve the performance and cycle life of cells into which the particles are incorporated as cathode components.

[0022] The particles are understood to be formed from or include grain boundaries containing the second composition, for example, the concentration of the enriched element in at least a portion of the grain boundary is higher than the concentration of the enriched element in adjacent primary crystallites, for example, measured by the atomic percentage of the enriched element relative to the metal in each composition. The concentration of the enriched element in the grain boundary containing such enriched element is optionally higher on average than the concentration of the enriched element in adjacent crystallites. The materials provided herein optionally have relatively uniform enriched elements within the crystallites. Whether uniform or not, the concentration of the enriched element in the grain boundary is higher on average in the crystallites adjacent to the grain boundary region than the concentration of the individual or combined enriched element. Optionally, the first composition provided includes a further outer coating layer which may be placed on the outer surface of the secondary particles to obtain coated secondary particles.

[0023] In some embodiments of the particles provided in the present invention, the first composition that forms the crystallites (collectively referred to herein as the bulk, as is optional) is composed of Li 1+a MO 2+bThe present invention includes polycrystalline layered lithium metal oxides defined by (Formula I) [wherein -0.1 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3], and optionally cells or batteries formed using the same. In some embodiments, a is -0.1, optionally 0, optionally 0.1, optionally 0.2. Optionally, a is -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 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 or greater. In some embodiments, b is -0.3, arbitrarily -0.2, arbitrarily -0.1, arbitrarily 0, arbitrarily 0.1, arbitrarily 0.2, arbitrarily 0.3. Arbitrarily, b is -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 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 or greater.

[0024] In some embodiments, it is understood that the Li in formula I does not have to be Li alone, 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 may be present in amounts of 10 atomic percent or less, 5 atomic percent or less, 3 atomic percent or less, or 2 atomic percent or less, where the percentages are relative to the total Li in the otherwise equivalent unsubstituted material.

[0025] In the first composition of Formula I, M contains a controlled concentration of Mn. Mn is optionally present in an amount of about 30 at% to about 70 at% or any value or range in between, relative to the total M. It has been found that the benefits of grain boundary enrichment are not observed at Mn concentrations of less than about 30 at%, more directly less than about 35 at%, or greater than about 70 at%, optionally greater than about 65 at%. For this reason, when Mn is present in an amount of about 30 at% to about 70 at%, and further enhanced to about 35 at% to about 65 at%, and combined with grain boundary enrichment with one or more enriching elements, optionally Co or Al, as also provided herein, a dramatic improvement in cycle life and / or rate capability is achieved compared to non-grain boundary enriched materials. Thus, the material of Formula I provided herein as a first composition, or as a second composition further comprising enrichment with one or more enriching elements, optionally comprises 30 at% to 70 at% of Mn in the total M of Formula I, and optionally 35 at% to 65 at% of Mn. Optionally, Mn is present in M ​​in an amount of 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% or more, and about 70, 69, 68, 67, 66 or 65 at% or less. Arbitrarily, Mn exists within M at approximately 45at%~65at%, 45at%~64at%, arbitrarily 45at%~63at%, arbitrarily 45at%~62at%, arbitrarily 45at%~61at%, arbitrarily 45at%~60at%, arbitrarily 40at%~70at%, 40at%~65at%, arbitrarily 40at%~64at%, arbitrarily 40at%~63at%, arbitrarily 40at%~62at%, arbitrarily 40at%~61at%, arbitrarily 40at%~60at%, arbitrarily 35at%~65at%, arbitrarily 35at%~64at%, arbitrarily 35at%~63at%, arbitrarily 35at%~62at%, arbitrarily 35at%~61at%, and arbitrarily 35at%~60at%.

[0026] In the first composition, M in formula 1 optionally contains Ni. The amount of Ni in the first composition is optionally 25 to 70 atomic percent (at%) of the total M. Optionally, the Ni component is 65 at% or less. Optionally, the Ni component is 60 at% or less. Optionally, the Ni component is 40 at% or less. Optionally, the Ni component is 35 at% or less. Optionally, the Ni component is 30 at% or less. Optionally, the Ni component of M is 70, 65, 60, 55, 50, 45, 40, 35, 30, or 25 at% or less. In some embodiments, Ni is absent.

[0027] The sum of at% Ni and at% Mn in the first composition, the second composition, or both is arbitrarily 70 at% or more. Optionally, the total at% of Ni and at% of Mn in the first composition, the second composition, or both is optionally about 75 at% or more, 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%, or optionally 100 at% in the first composition.

[0028] In some embodiments, M in the first composition is Mn and Ni only, or a combination of Mn and Ni or Co or both and one or more additional elements, or a combination of Mn and one or more additional elements. The additional elements are optionally metals. Optionally, the additional elements 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 embodiments, the additional elements may include Mg, Co, Al, or combinations thereof. Optionally, the additional elements may be Mg, Al, V, Ti, B, or combinations thereof. Optionally, the additional elements are selected from the group consisting of Mg, Al, V, Ti, or B. Optionally, the additional elements are selected from the group consisting of Co and Al. Optionally, the additional elements are selected from the group consisting of Ca, Co, and Al. Optionally, the additional element is Co.

[0029] The additional elements in the first composition may be present in amounts of approximately 1 at% to approximately 55 at%, specifically approximately 5 at% to approximately 55 at%, and more specifically approximately 10 at% to approximately 55 at%, of M in the first composition. Optionally, the additional elements may be present in amounts of approximately 1 at% to approximately 20 at%, specifically approximately 2 at% to approximately 18 at%, and more specifically approximately 4 at% to approximately 16 at%, of M in the first composition. In some exemplary examples, M consists of approximately 25 to 70 at% Ni, approximately 0 to 15 at% Co, approximately 30 to 70 at% Mn, and approximately 0 to 10 at% of the additional elements. In the example, M consists of approximately 25 to 70 at% Ni, 0 to 15 at% Co, 30 to 70 at% Mn, and 0 to 10 at% of the additional elements, with the total of Ni and Mn being 75 at% or more. In some exemplary examples, M is approximately 30–50 at% Ni, 0.01–10 at% Co, 30–70 at% Mn, and 0–10 at% of additional elements. Optionally, M contains approximately 30–70 at% Mn and approximately 25–50 at% Ni, with the combined total of Mn and Ni being at least 80 at%, and also contains approximately 0–15 at% Co and approximately 0–5 at% Mg. Optionally, M contains approximately 30–70 at% Mn, approximately 25–50 at% Ni, approximately 0–15 at% Co, and approximately 0–5 at% Mg. It is understood that the total at% of M is equal to 100.

[0030] In some embodiments, the first composition portion that partially or entirely forms crystallites optionally has a layered α-NaFeO2 type structure, a cubic structure, a spinel structure, or a combination thereof.

[0031] In certain embodiments, secondary particles have enriched grain boundaries, and optionally, the atomic percentage of one or more enriching elements in the grain boundaries is higher than the atomic percentage of the same element in the crystallite, optionally as an average across the entire crystallite and optionally as an average across adjacent crystallites. Referring to Figure 1 as an illustrative diagram, grain boundaries 20, 21 are located between adjacent crystallites 10 and comprise a second composition. The second composition may be as described in U.S. Patent Nos. 9,391,317 and 9,209,455, but any enriching elements described herein may be independently enriched in the grain boundaries with respect to the concentration of that enriching element in the crystallite and must be combined with the adjusted amounts of Mn provided herein.

[0032] In some embodiments, the second composition forming the grain boundary partially or entirely optionally has a layered α-NaFeO2 type structure, a cubic structure, a spinel structure, or a combination thereof. As described above, the concentration of one or more enriching elements in the grain boundary may be higher than the concentration of one or more enriching elements in the crystallite. A specific example is an embodiment in which the grain boundary has a layered α-NaFeO2 type structure. Another specific example is an embodiment in which the grain boundary has a defective α-NaFeO2 type structure. Another specific example is an embodiment in which part of the grain boundary has a cubic or spinel structure.

[0033] More specifically, the Mn-rich LiMO materials provided herein optionally match the LiMO2 structure having the R-3M space group. In some embodiments, the crystallites, grain boundaries or both include a mixture of phases including the monoclinic Li2MnO3 structure. Thus, in some embodiments, the materials provided herein are optionally a heterogeneous mixture of phase structures. In some embodiments, the materials provided herein include grain boundaries with a dominant LiMO2 structure having the R-3M space group, optionally including grain boundaries that are entirely of the LiMO2 structure having the R-3M space group. In some embodiments, the materials provided herein include a plurality of crystallites with a dominant LiMO2 structure having the R-3M space group, optionally including a plurality of crystallites that are entirely of the LiMO2 structure having the R-3M space group. In some embodiments, the grain boundaries, crystallites or both include a mixture of the LiMO2 structure and the Li2MO3 structure. Optionally, the Li2MO3 structure is a layered-layered Li2MO3-LiMO2 structure.

[0034] The second composition that is partially or wholly present within the grain boundary optionally has the composition Li 1+a M’O 2+bThe composition comprises a lithium metal oxide defined by formula (II) [wherein -0.1 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3]. Optionally, the second composition and the first composition are identical to the first composition except that the second composition contains one or more enriching elements, optionally Co, Al, or both Co and Al, or their concentrations are increased. In some embodiments 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. Arbitrarily, a is -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 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 or greater. In some embodiments, b is -0.3, arbitrarily -0.2, arbitrarily -0.1, arbitrarily 0, arbitrarily 0.1, arbitrarily 0.2, arbitrarily 0.3, arbitrarily 0.4, arbitrarily 0.5, arbitrarily 0.6, arbitrarily 0.7, arbitrarily 0.8, arbitrarily 0.9, arbitrarily 1.0, arbitrarily 1.1, arbitrarily 1.2, or arbitrarily 1.3.Arbitrarily, b is -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 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 or greater.

[0035] In formula II, as in formula I, M' optionally contains Mn at an adjusted concentration. Mn is optionally present in an amount of 10 at% to 70 at% or any value or range in between relative to the total M'. The materials of formula II provided herein optionally contain 10 at% to 70 at% of the total M' in formula II, optionally 30 at% to 70 at% of Mn, and optionally 35 at% to 65 at% of Mn. Arbitrarily, Mn exists in M' at a concentration of 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% or more, and approximately 70, 69, 68, 67, 66 or 65 at% or less. Arbitrarily, Mn exists in M' at approximately 45at%~65at%, 45at%~64at%, arbitrarily 45at%~63at%, arbitrarily 45at%~62at%, arbitrarily 45at%~61at%, arbitrarily 45at%~60at%, arbitrarily 40at%~70at%, 40at%~65at%, arbitrarily 40at%~64at%, arbitrarily 40at%~63at%, arbitrarily 40at%~62at%, arbitrarily 40at%~61at%, arbitrarily 40at%~60at%, arbitrarily 35at%~65at%, arbitrarily 35at%~64at%, arbitrarily 35at%~63at%, arbitrarily 35at%~62at%, arbitrarily 35at%~61at%, and arbitrarily 35at%~60at%. In some embodiments, Mn is not present in the second composition.

[0036] In formula II, M' optionally contains Ni. Ni is present in any value or range between 10 at% and 70 at% of the total M'. The materials of formula II provided herein optionally contain 10 at% to 70 at% and optionally 25 at% to 70 at% Ni of the total M' in formula II. Arbitrarily, Ni is present in M' at a concentration of 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% or more. Optionally, Ni is present in M' at a concentration of 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% or less. Optionally, Ni is not present in the second composition.

[0037] Examples of enriching elements that may potentially be included in M' of formula II to form grain boundary enriched secondary particles include various elements that can substitute for Ni in the structure. For example, when the material is charged, Ni 3+ If the trivalent (3+) ions of doping elements that can directly substitute for Ni are less susceptible to oxidation than Ni ions, they promote the beneficial cycling properties observed in the materials described herein. Substitution of Ni(III) with Al(III) is one example. If the tetravalent (4+) ions are Ni 3+When ions are substituted, they are charge-compensated by 2+ Ni ions, and their inductive effect raises the potential at which these Ni ions are oxidized to the 4+ state. Substitution of Ni(III) by Mn(IV) is one example. Alternatively, when less oxidizable 2+ ions substitute for Ni, they are charge-compensated by 4+ Ni ions. Substitution of Ni(III) by Mg(II) is one example. To substitute Ni in a LiM'O2 structure, doping ions may be roughly the same size as the Ni ions and can increase the local oxidation potential. The relative effect of a given ion on the oxidation potential is often Ni 3+ It can be estimated from the ionization energy of Ni. 3+ Ions of similar size and having similar or higher ionization energies may potentially help stabilize grain boundaries in oxidized cathodes. The table below shows the ionization energies and hexa-coordinate (octahedral environment) ionic radii of ions that may stabilize grain boundaries in charged high-Ni LiMO2 cathode materials, for example.

[0038] [Table 1]

[0039] Thus, in the second composition, M' further comprises one or more enriching elements that can be selected from the group that are less susceptible to oxidation than nickel when electrochemically charged to 4.3V or higher relative to the Li metal anode. In one example, M' may comprise Ni and a combination of Co and Mn that are less susceptible to oxidation than nickel when charged to 4.3V or higher, optionally 4.6V. In other embodiments, M' may comprise Ni, Mn, and one or more elements selected from the group that are less susceptible to oxidation than Ni when charged to 4.3V relative to lithium metal, including Cr, Fe, Ti, V, Co, Cu, Zn, Zr, Nb, Sb, W, Sc, Al, Mo, Y, etc. Optionally, M' may not comprise Ni and 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 enriching elements provided herein. In some embodiments, M' may include elements selected from the group of elements that do not oxidize when lithium is charged to 4.3V, such as Y, Sc, Ga, In, Tl, Si, Ge, Sn, Pb, etc.

[0040] The M' given in the second composition optionally contains one or more enriching elements, optionally Co, Al, or both, at a higher concentration than such elements in the crystallites described herein.

[0041] Optionally, the Li in the second composition (grain boundaries) does not have to be Li alone, but may be partially substituted with one or more Li-enriched elements selected from the group consisting of Mg, Sr, Na, K, and Ca. The one or more Li-enriched elements may be present in amounts of 10 atomic percent or less, 5 atomic percent or less, 3 atomic percent or less, or 2 atomic percent or less, where the percentage is relative to the total Li in the material in its state at the time of manufacture.

[0042] For any material provided herein, the nominal or overall compositional composition of the secondary particles (characterized, e.g., by elemental mapping from SEM), optionally the first composition, or optionally the second composition, or both, are defined by the general formula LiMO [wherein M is Mn and Ni, and optionally one or more additional elements], and the second composition must contain one or more enriching elements. As an example, the mole fraction of Co and / or Al defining the composition of the crystallite, if present, is lower than the total mole fraction of Co and / or Al alone or combined in the entire particle composition as determined by elemental mapping. The mole fraction of enriching elements alone or combined in the crystallite may be zero. The mole fraction of enriching elements alone or combined in the grain boundaries is higher than the mole fraction of enriching elements alone or combined in the entire particle as measured by elemental mapping. Note that this is merely an example, as Co, Al, or both may be replaced or added by one or more other enriching elements, as shown herein.

[0043] The second composition located within the grain boundary contains Co or Al or one or more other enriching elements, provided that the concentration of Co or Al, or one or more other enriching elements individually or combined, within the grain boundary is higher than the concentration of Co or Al, or one or more other enriching elements individually or combined, within the grain boundary, and optionally the concentration of Co within the grain boundary is higher than the concentration of Co in the crystallite, optionally the concentration of Al within the grain boundary is higher than the concentration of Al in the crystallite, or the concentration of one or more other enriching elements is higher than the concentration of one or more enriching elements in the crystallite. As a non-limiting example, it has been found that a process capable of enriching enriching elements within grain boundaries can be used to supplement a liquid solution containing 0 at% to 8 at% of Co, optionally 3 at% to 5 at%, relative to the total transition metals of the first composition to be enriched, with 0.01 at% to 10 at% Al, and optionally 1.5 at% or less Al, and the added Co and Al are incorporated into the grain boundaries of the secondary particles.

[0044] As the primary particle size distribution changes with changes in the overall composition and synthesis conditions, the volume fraction of grain boundaries within a given secondary particle fluctuates, and therefore the final concentration of one or more enriching elements in the grain boundaries may vary between different secondary particles and even within individual secondary particles, but is still always higher than the concentration of one or more enriching elements in adjacent crystallites or in the crystallite as a whole. For this reason, it is most useful to specify the amount of enriching elements added to the grain boundaries with respect to the composition of the crystallite. In some embodiments, the amount of one or more enriching elements is similar to the amount described for Co in U.S. Patent No. 11,424,449 or U.S. Patent No. 10,501,335, but in this disclosure, the crystallite and optionally the grain boundaries also further contain Mn in adjusted or substantially adjusted concentrations, as otherwise described herein.

[0045] The electrochemical active materials provided herein may be in the form of secondary particles. The secondary particles have a particle size defined as the size of the secondary particle measured from one outer edge to the opposite outer edge and substantially passing through the center of the secondary particle. The particle size or average particle size (the overall average of all particles of the same composition) of the first composition is arbitrarily about 1 μm to about 25 μm, or any value or range in between. Optionally, the first composition has particle sizes or average particle sizes of approximately 1 μm, optionally approximately 2 μm, optionally approximately 3 μm, optionally approximately 4 μm, optionally approximately 5 μm, optionally approximately 6 μm, optionally approximately 7 μm, optionally approximately 8 μm, optionally approximately 9 μm, optionally approximately 10 μm, optionally approximately 11 μm, optionally approximately 12 μm, optionally approximately 13 μm, optionally approximately 14 μm, optionally approximately 15 μm, optionally approximately 16 μm, optionally approximately 17 μm, optionally approximately 18 μm, optionally approximately 19 μm, optionally approximately 20 μm, optionally 21 μm, optionally approximately 22 μm, optionally 23 μm, optionally approximately 24 μm, and optionally 25 μm. Optionally, the particle size or average particle size of the first composition is approximately 1 μm to approximately 15 μm, and optionally approximately 1 μm to approximately 10 μm.

[0046] Each crystallite can have any preferred shape, which may be the same or different within each secondary particle. Furthermore, the shape of each crystallite may be the same or different in different secondary particles. Due to its crystallinity, a crystallite may be faceted, may have multiple flat faces, and the shape of a crystallite may approximate a geometric shape. In some embodiments, a crystallite may be fused with adjacent crystallites whose crystal planes are mismatched. A crystallite may be arbitrarily polyhedron. A crystallite may have a linear shape, and when viewed in cross-section, part or all of the crystallite may be linear. A crystallite may be square, hexagonal, rectangular, triangular, or a combination thereof. The length, width, and thickness of a crystallite can be independently selected, and the length, width, and thickness of a crystallite may be about 5 to about 1000 nanometers (nm), more specifically about 10 to about 900 nm, and more specifically about 20 to about 800 nm, respectively.

[0047] The materials provided herein can be prepared by synthesizing a green from at least two components in powder form, which may optionally comprise a pulverized (or non-pulverized) lithium hydroxide or its hydrate, and a precursor hydroxide containing Mn and optionally one or more other elements, the precursor hydroxide optionally obtained by a coprecipitation process. In this case, the electrochemical active materials provided herein can be produced by adjusting the conditions under which the formation of the metal hydroxide occurs.

[0048] In some embodiments, the precursor hydroxide may be a mixed metal hydroxide. In some embodiments, the mixed metal hydroxide may comprise a metal composition of Mn, Ni, and optionally Co. Optionally, the mixed metal hydroxide comprises 30-70 at% Mn, 25-70 at% Ni, 0-15 at% Co, and 0-5 at% Mg as metal components. Optionally, the mixed metal hydroxide comprises 25-70 at% Ni, 0-30 at% Co, and 30-70 at% Mn. Optionally, the mixed metal hydroxide comprises 25-70 at% Ni, 0-30 at% Co, 0-10 at% Al, and 30-70 at% Mn. Optionally, the mixed metal hydroxide comprises 25-70 at% Ni, 0-30 at% Co, 0-10 at% Al, and 30-70 at% Mn. Optionally, the mixed metal hydroxide contains 35-65 at% Ni, 0-30 at% Co, 0-10 at% Al, and 35-65 at% Mn. Optionally, the metals of the mixed metal hydroxide are approximately 40 at% Ni, 56 at% Mn, and 4 at% Co. Optionally, the metals of the mixed metal hydroxide are approximately 61 at% Ni, 35 at% Mn, and 4 at% Co. Optionally, the metals of the mixed metal hydroxide are approximately 26 at% Ni, 70 at% Mn, and 4 at% Co. Optionally, the metals of the mixed metal hydroxide are approximately 31 at% Ni, 65 at% Mn, and 4 at% Co. Optionally, the metals of the mixed metal hydroxide are approximately 36 at% Ni, 60 at% Mn, and 4 at% Co. For example, precursor hydroxides may be produced by precursor suppliers such as Hunan Brunp Recycling Technology Co. Ltd. using standard methods for preparing nickel hydroxide-based materials.

[0049] Secondary particles can be formed by a multi-step process in which primary material particles are formed and then sintered to establish clear grain boundaries, and optionally the primary particles have an α-NaFeO2 structure with few or no observable defects. The particles are then subjected to a liquid process in which one or more enriching elements, optionally Co, are applied at a desired concentration level, followed by drying and then heat treatment, which selectively moves the precipitated enriching element species on the surface to the grain boundaries, thereby forming secondary particles with enriching elements, optionally Co and / or Al, at higher concentrations at the grain boundaries than in the crystallites. As an example, according to the method for producing high-Mn-level Ni, Co, and Mn-based secondary particles provided herein, the formation may include: combining a lithium compound with one or more metal or metalloid hydroxide precursor compounds (e.g., a combination of Ni, Co, and Mn pre-produced by a coprecipitation reaction, etc.) to form a mixture; heat-treating the mixture at about 30 to about 200°C to form a dry mixture; heat-treating the dry mixture at about 200 to about 500°C for about 0.1 to about 5 hours; and then heat-treating at 600°C to less than about 1000°C for about 0.1 to about 10 hours to produce secondary particles. The maximum temperature of the initial calcination is relative and specific to the material used for the hydroxide precursor. Optionally, the maximum temperature in the first firing may be 950 degrees Celsius or lower, optionally 900 degrees Celsius or lower, optionally 850 degrees Celsius or lower, optionally 800 degrees Celsius or lower, optionally 750 degrees Celsius or lower, optionally 720 degrees Celsius or lower, optionally 715 degrees Celsius or lower, optionally 710 degrees Celsius or lower, optionally 705 degrees Celsius or lower, or optionally 700 degrees Celsius or lower. Optionally, the maximum temperature in the first firing may be approximately 1000 degrees Celsius or lower. Optionally, the maximum temperature may be approximately 950 degrees Celsius or lower. Optionally, the maximum temperature may be approximately 900 degrees Celsius or lower. Optionally, the maximum temperature may be approximately 850 degrees Celsius or lower. Optionally, the maximum temperature may be approximately 800 degrees Celsius or lower. Optionally, the maximum temperature may be approximately 750 degrees Celsius or lower. Optionally, the maximum temperature may be approximately 700 degrees Celsius or lower. The maximum temperature may be arbitrarily set to approximately 660 degrees Celsius or lower. The maximum temperature may be arbitrarily set to approximately 640 degrees Celsius or lower.In other embodiments, the maximum temperature may be less than approximately 700 degrees Celsius, 695 degrees Celsius, 690 degrees Celsius, 685 degrees Celsius, 680 degrees Celsius, 675 degrees Celsius, 670 degrees Celsius, 665 degrees Celsius, 660 degrees Celsius, 655 degrees Celsius, 650 degrees Celsius, 645 degrees Celsius, or 640 degrees Celsius. The residence time at the maximum temperature is arbitrarily less than 10 hours. Arbitrarily, the residence time at the maximum temperature may be 8 hours or less, arbitrarily 7 hours or less, arbitrarily 6 hours or less, arbitrarily 5 hours or less, arbitrarily 4 hours or less, arbitrarily 3 hours or less, or arbitrarily 2 hours or less.

[0050] After calcination, the subsequent processing may include grinding the calcined material in a mortar and pestle so that the resulting powder passes through a desired sieve, optionally a #35 sieve. The powder is then optionally jar-milled in a 1-gallon jar using a 2cm drum YSZ medium for optionally 5 minutes, or for a time sufficient for the material to optionally pass through a #270 sieve.

[0051] The product of the first calcination or milling may be subsequently treated in a manner that optionally results in enriched grain boundaries after a second calcination. The process of enriching the grain boundaries within the primary particles can be carried out by the methods or compositions described in U.S. Patent Nos. 9,391,317 and 9,209,455, where the applied process uses a liquid solution containing a certain level of enriching element, optionally Co and / or a certain level of Al. The grain boundary enriching element can optionally be applied by suspending the milling product in an aqueous slurry containing one or more enriching elements and a lithium compound, optionally at a temperature of about 60 degrees Celsius, thereby ensuring that the enriching element, optionally Co and / or Al, is present in the aqueous solution at the concentrations described herein. The slurry can then be spray-dried to form a flowable powder, which can subsequently be subjected to a second calcination using a heating curve that optionally follows a two-stage heating / holding process. The first two-stage heating / holding temperature profile can be set at an arbitrary rate of 5 degrees Celsius per minute from ambient temperature (approximately 25 degrees Celsius) to 450 degrees Celsius, and the temperature can be held at 450 degrees Celsius for 1 hour. Subsequently, the second heating / holding stage can be set at a rate of 2 degrees Celsius per minute from 450 degrees Celsius to the maximum temperature, and the temperature can be held at the maximum temperature for 2 hours. In some embodiments, the maximum temperature is less than approximately 725 degrees Celsius, optionally 700 degrees Celsius or approximately 700 degrees Celsius. In other embodiments, the maximum temperature is approximately 700 degrees Celsius, optionally 750 degrees Celsius.

[0052] It has been found that by combining the initial firing at the aforementioned maximum temperature with a process of applying grain boundary enriching elements, followed by a second firing similarly, the resulting particles with an adjusted Mn concentration can be used as a cathode to significantly improve the reduction of capacity degradation and / or increase rate capability. Such a combination has been found to result in an additional cycle life that significantly improves the electrochemical performance of the material, while simultaneously dramatically reducing costs compared to conventional high-Ni and high-Co materials. Thus, in some embodiments, the particles have a Li composition. 1+a MO 2+bIt is understood that the first composition comprises a plurality of crystallites comprising a polycrystalline layered structure of a lithium metal oxide defined by [wherein -0.1 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3]. In some embodiments, a is -0.1, arbitrarily 0, arbitrarily 0.1, arbitrarily 0.2, arbitrarily 0.3, arbitrarily 0.4, arbitrarily 0.5, arbitrarily 0.6, arbitrarily 0.7, arbitrarily 0.8, arbitrarily 0.9, arbitrarily 1.0, arbitrarily 1.1, arbitrarily 1.2, or arbitrarily 1.3. Arbitrarily, a is -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 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 or greater. In some embodiments, b is -0.3, arbitrarily -0.2, arbitrarily -0.1, arbitrarily 0, arbitrarily 0.1, arbitrarily 0.2, arbitrarily 0.3, arbitrarily 0.4, arbitrarily 0.5, arbitrarily 0.6, arbitrarily 0.7, arbitrarily 0.8, arbitrarily 0.9, arbitrarily 1.0, arbitrarily 1.1, arbitrarily 1.2, or arbitrarily 1.3.Arbitrarily, b is -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 The values ​​are 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 or greater. The crystallites have a certain concentration of Mn. Mn is present in any value or range between 30 at% and 70 at% of the total M. It was found that the benefits of grain boundary enrichment are not observed at Mn concentrations of less than 30 at%, more directly, less than 35 at% or greater than 70 at%, and optionally greater than 65 at%. The first composition optionally contains 30 at% to 70 at% of total Mn, and optionally 35 at% to 65 at% of Mn. Optionally, Mn is present in M ​​at concentrations of 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% or more, and 70, 69, 68, 67, 66 or 65 at% or less. Optionally, Mn is present in M ​​at concentrations of 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%, and optionally 35 at% to 60 at%. The crystallites contain Ni in an amount of 25 to 70 atomic percent (at%) of the M element. The amount of Ni in the first composition is optionally 25 to 69 atomic percent (at%) of the total M. Optionally, the Ni component is 65 at% or less. Optionally, the Ni component is 60 at% or less. Optionally, the Ni component is 40 at% or less.Optionally, the Ni component is 35 at% or less. Optionally, the Ni component is 30 at% or less. Optionally, the Ni component of M is 70, 65, 60, 55, 50, 45, 40, 35, 30, or 25 at% or less. Component M may contain one or more additional elements. The additional elements are optionally metals. Optionally, the additional elements may contain one or more of Al, Mg, Co, Mn, Ca, Sr, Zn, Ti, Y, Cr, Mo, Fe, V, Si, Ga, or B. In certain embodiments, the additional elements may be Mg, Co, Al, or a combination thereof. Optionally, the additional elements may be Mg, Al, V, Ti, B, or a combination thereof. Optionally, the additional elements consist of Mg, Al, V, Ti, and B. The additional elements of the first composition may be present in the first composition in an amount of about 1 to about 90 at%, specifically about 5 to about 80 at%, and more specifically about 10 to about 70 at%. Optionally, the additional elements of the first composition may be present in the first composition in an amount of about 0 to about 70 at%, specifically about 5 to about 70 at%, and more specifically about 10 to about 70 at% of M. Optionally, the additional elements may be present in the first composition in an amount of about 1 to about 20 at%, specifically about 2 to about 18 at%, and more specifically about 4 to about 16 at% of M. In such materials, grain boundaries can be enriched with one or more enriching elements, optionally Co, Al, or both, at a concentration optionally 0.1 to 10 at% higher than the concentration of one or more enriching elements in the crystallite.

[0053] In the electrochemical cells provided herein, the particles provided herein are optionally used as the electrochemical active material, having an initial discharge capacity of 110 mAh or more per gram of particle, 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, or optionally 250 mAh / g.

[0054] As shown in Figure 1, a particle is disclosed comprising a crystallite 10 containing a first composition and grain boundaries 20, 21 containing a second composition, wherein the concentration of one or more enriching elements, optionally Co, Al, or a combination thereof, in the grain boundaries is higher than the concentration of one or more enriching elements in the crystallite. The particle comprises multiple crystallites and is referred to as a secondary particle. Optionally, an outer layer, such as a passivation layer or protective layer, as shown by 30 in Figure 1, may be deposited on the outer surface of the particle. The outer layer may completely or partially cover the secondary particle. The layer may be amorphous or crystalline. The layer may contain oxides, phosphates, pyrophosphates, fluorophosphates, carbonates, fluorides, oxyfluorides, or combinations thereof of elements such as Al, Ti, B, Li, or Si, or combinations thereof. In some embodiments, the outer layer contains borates, aluminates, silicates, fluoroaluminates, or combinations thereof. Optionally, the outer layer contains carbonates. Optionally, the outer layer may contain ZrO2, Al2O3, TiO2, AlPO4, AlF3, B2O3, SiO2, Li2O, Li2CO3, or a combination thereof. Optionally, the outer layer may contain AlPO4 or Li2CO3, or be AlPO4 or Li2CO3. The layers may be deposited and positioned by any process or technique that does not adversely affect the desired properties of the particles. Typical methods include, for example, spray coating and immersion coating.

[0055] Electrodes are also provided that contain the secondary particles described herein as a single component or sole electrochemical active material. The secondary particles provided herein may optionally be included as the active component of the cathode. The cathode may optionally contain the secondary particles disclosed above as the active material and further contain a conductive agent and / or a binder. The conductive agent may include any conductive agent that provides desirable properties and may be amorphous, crystalline, or a combination thereof. Examples of conductive agents include carbon black, e.g., acetylene black or lamp black, mesocarbon, graphite, graphene, carbon fiber, carbon nanotubes, e.g., single-walled carbon nanotubes or multi-walled carbon nanotubes, or a combination thereof. The binder may be any binder that provides desirable properties, such as polyvinylidene fluoride, copolymer of polyvinylidene fluoride and hexafluoropropylene, poly(vinyl acetate), poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate), poly(methyl methacrylate-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, acrylonitrile-butadiene-styrene, sulfonated styrene / ethylene-butylene / styrene triblock polymer, polyethylene oxide, or combinations thereof.

[0056] A cathode can be prepared by combining the particles, conductive agent (if present), and binder described herein in a suitable ratio, for example, about 80 to about 98 weight percent of active particles, about 1 to about 20 weight percent of conductive agent, and about 1 to about 10 weight percent of binder, based on the total weight of the particles, conductive agent, and binder combined. The particles, conductive agent, and binder can be suspended in a suitable solvent such as N-methylpyrrolidinone, placed on a suitable substrate such as aluminum foil, and dried in air. Note that this substrate and solvent are presented for illustrative purposes only. Other suitable substrates and solvents can be used or combined to form a cathode.

[0057] The cathodes provided herein, when cycled in a 2025 coin cell using an MCMB 10-28 graphite anode, a polyolefin separator, and an electrolyte of 1M LiPF6 in 1 / 1 / 1 (volume) EC / DMC / EMC containing 1 wt% VC, optionally exhibit a significant reduction in capacity degradation compared to similar Mn-rich materials without grain boundary enrichment. Plotting the capacity measurements against the number of cycles yields a curve with a specified slope. If the high-Mn (e.g., 30-70 at% Mn) active particle materials described herein have grain boundary enrichment with one or more enriching elements described herein, optionally Co and / or Al, the slope of the capacity curve is smaller compared to particles without such grain boundary enrichment. In some embodiments, the cell capacity degradation is less than 10% over the first 200 cycles and optionally less than 5% over the first 100 cycles.

[0058] An electrochemical cell is also provided, using the electrochemically active cathode material provided herein as the active material in the cathode and paired with a suitable anode. The electrochemical cells provided herein are optionally used with the electrochemical active material particles provided herein in a cathode having an initial discharge capacity of optionally 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, or optionally about 250 mAh / g or more, and optionally demonstrate that the cell capacity degradation is 10% or less over the first 200 cycles and 5% or less over the first 100 cycles. In some embodiments, the cell capacity degradation is 15% or less over the first 400 cycles, and optionally 5% or less over the first 200 cycles. Optionally, the cell capacity degradation is 10% or less 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%, and optionally less than 2% over the first 200 cycles. Optionally, the cell capacity degradation is 15% or less 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%, and optionally less than 3% over the first 300 cycles. Arbitrarily, the cell capacity degradation is less than 20% over the first 400 cycles, arbitrarily less than 19% over the first 400 cycles, arbitrarily less than 18%, arbitrarily less than 17%, arbitrarily less than 16%, arbitrarily less than 15%, arbitrarily less than 14%, arbitrarily less than 13%, arbitrarily less than 12%, arbitrarily less than 11%, arbitrarily less than 10%, arbitrarily less than 9%, arbitrarily less than 8%, arbitrarily less than 7%, arbitrarily less than 6%, arbitrarily less than 5%, arbitrarily less than 4%, and arbitrarily less than 3%.

[0059] The electrochemical cell may be, for example, a lithium-ion cell, a lithium polymer cell, or a lithium cell. The cell may include a cathode, an anode, and a separator inserted between the cathode and the anode. The battery may include one cell or two or more cells.

[0060] The separator may be a microporous membrane, a porous film containing polypropylene, polyethylene, or a combination thereof, or a woven or nonwoven material such as a glass fiber mat. Certain other separators known in the art may also be used.

[0061] The anode may include a coating on the current collector. The coating may include, for example, suitable carbon, such as graphite, coke, hard carbon, or mesocarbon such as mesocarbon microbeads. The current collector may be, for example, copper foil.

[0062] In other embodiments, the anode active material may be a titanium oxide optionally containing nanowires such as TiO2-B nanowires, as described in Armstrong, et al., Journal of Power Sources, 146, no. 1-2 (2005): 501-506. An exemplary example of a titanium oxide is lithium titanium oxide (LTO). Lithium titanium oxide may have a spinel-type structure. The anode may optionally be of the formula Li 4+a Ti5O 12+b (IV) [wherein -0.3 ≤ a ≤ 3.3 and -0.3 ≤ b ≤ 0.3] may include an anodic electrochemical active material. In some embodiments, lithium titanium oxide is expressed as formula III Li 4+y Ti5O 12 (III) [In the equation, 0 ≤ y ≤ 3, 0.1 ≤ y ≤ 2.8, or 0 ≤ y ≤ 2.6] It can be anything.

[0063] Alternatively, lithium titanium oxide is used in formula IV. Li 3+zTi 6-z O 12 (IV) [In Equation IV, 0 ≤ z ≤ 1, arbitrarily 0 ≤ z ≤ 1, 0.1 ≤ z ≤ 0.8 or 0 ≤ z ≤ 0.5. A combination of anodic electrochemical active materials containing at least one of the aforementioned lithium titanium oxides may be used. In some embodiments, the anodic electrochemical active material is Li4Ti5O 12 Contains or Li4Ti5O 12 [is] It can be anything.

[0064] The anode current collector or cathode current collector can be formed from, for example, Ti, Al, Cu, etc. The current collector may be in the form of foil, perforated foil, screen, or other preferred configuration. The cathode current collector may be in electrical contact with the cathode active material provided herein. The anode current collector may be in electrical contact with the anode active material provided herein.

[0065] An electrochemical cell also includes an electrolyte that may be in contact with a positive electrode (cathode), a negative electrode (anode), and a separator. The electrolyte may include an organic solvent and a lithium salt. The organic solvent may be a linear or cyclic carbonate. Typical organic solvents include ethylene carbonate (EC), propylene carbonate, butylene carbonate, trifluoropropylene carbonate, γ-butyrolactone, sulfolane, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 3-methyl-1,3-dioxolane, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate (DMC), diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, methylpropyl carbonate, propanesultone, or combinations thereof. In another embodiment, the electrolyte is a polymer electrolyte.

[0066] Optionally, the electrolyte does not contain ethylene carbonate. Optionally, the electrolyte contains DMC and one or more other additives or cosolvents, and does not contain EC. Optionally, the electrolyte contains DMC and two additives, optionally three additives, optionally four additives, or optionally five additives. Optionally, the electrolyte contains DMC, LiPF6 and two additional additives, optionally three additional additives, optionally four additional additives, or optionally five additional additives.

[0067] Furthermore, the selective additives in the electrolytes used in the batteries provided herein are less toxic than organic sulfates and sultone-type additives. Exemplary 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 cosolvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some embodiments, the additives optionally include combinations of fluoroethylene carbonate, difluoroethylene carbonate, and lithium difluoro(oxalato)borate.

[0068] Additives are optionally present in the electrolyte at concentrations of less than 5 wt% by weight, depending on the additive. Optionally, additives are present at concentrations of 5 wt%, 4.5 wt%, 4 wt%, 3.5 wt%, 3 wt%, 2.5 wt%, 2 wt%, 1.5 wt%, 1 wt%, 0.5 wt%, or 0.1 wt% or less.

[0069] In some embodiments, the additive in the electrolyte is present in amounts of arbitrarily greater than 0.1 wt%, arbitrarily greater than 0.5 wt%, arbitrarily greater than 1 wt%, arbitrarily greater than 1.5 wt%, arbitrarily greater than 2 wt%, arbitrarily greater than 2.5 wt%, arbitrarily greater than 3 wt%, arbitrarily greater than 3.5 wt%, arbitrarily greater than 4 wt%, arbitrarily greater than 4.5 wt%, and arbitrarily greater than 5 wt%.

[0070] Optionally, the electrolyte includes DMC and FEC, with FEC present in amounts greater than 0.1 wt%, optionally 0.5 wt%, optionally greater than 1 wt%, optionally greater than 1.5 wt%, optionally greater than 2 wt%, optionally greater than 2.5 wt%, optionally greater than 3 wt%, optionally greater than 3.5 wt%, optionally greater than 4 wt%, optionally greater than 4.5 wt%, optionally greater than 5 wt%, and optionally greater than 6 wt%. In some embodiments, the range of FEC is 1.5 wt% to 6 wt%, optionally 2 wt% to 5 wt%.

[0071] Optionally, the electrolyte includes DMC and F2EC, where F2EC is present in amounts greater than 0.1 wt%, optionally 0.5 wt%, optionally greater than 1 wt%, optionally greater than 1.5 wt%, optionally greater than 2 wt%, optionally greater than 2.5 wt%, optionally greater than 3 wt%, optionally greater than 3.5 wt%, optionally greater than 4 wt%, optionally greater than 4.5 wt%, and optionally greater than 5 wt%. In some embodiments, the range of F2EC is 1.5 wt% to 6 wt%, optionally 2 wt% to 5 wt%.

[0072] In some embodiments, the electrolyte comprises DMC and TMSPO4, with TMSPO4 present at less than 5 wt%. Arbitrarily, TMSPO4 is present at 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%, and optionally 0.1 wt% or less. In some embodiments, the TMSPO4 range is 0.1 wt% to 3 wt%, and optionally 0.5 wt% to 2 wt%.

[0073] In some embodiments, the electrolyte includes DMC and TMSM, with TMSM present in amounts less than 5 wt%. TMSM is present in amounts of 5 wt%, 4.5 wt%, 4 wt%, 3.5 wt%, 3 wt%, 2.5 wt%, 2 wt%, 1.5 wt%, 1 wt%, 0.5 wt%, and 0.1 wt% or less. In some embodiments, the TMSM range is 0.1 wt% to 3 wt%, and 0.5 wt% to 2 wt%.

[0074] In some embodiments, the electrolyte includes DMC and TMSPi, with TMSPi present at less than 5 wt%. TMSPi is present at 5 wt%, 4.5 wt%, 4 wt%, 3.5 wt%, 3 wt%, 2.5 wt%, 2 wt%, 1.5 wt%, 1 wt%, 0.5 wt%, and 0.1 wt% or less. In some embodiments, the range of TMSPi is 0.1 wt% to 3 wt%, and 0.5 wt% to 2 wt%.

[0075] In some embodiments, the electrolyte comprises DMC and a cosolvent TFETFPE, where TFETFPE is present in less than 20 wt% depending on the additive. Optionally, TFETFPE is present in 15 wt%, and optionally 10 wt% or less. In some embodiments, TFETFPE is present in 1 wt% to 20 wt%, or any value or range in between, and optionally 2 wt% to 10 wt%.

[0076] Representative lithium salts useful as electrolytes include, but are not limited to, LiPF6, LiBF4, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiN(SO2C2F5)2, LiSbF6, LiC(CF3SO2)3, LiC4F9SO3, and LiAlCl4. The lithium salt may be present in the electrolyte at concentrations of 0.1 mol (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, and optionally 2.0 M or higher. The lithium salt may be dissolved in an organic solvent. A combination containing at least one of the above can be used. The concentration of lithium salt in the electrolyte may be 0.1 to 2.0 M.

[0077] The concentration of lithium salt, if present, is arbitrarily 1.0 M or higher, arbitrarily 1.3 M or 2.0 M or higher. By using certain additives, such as fluoroethylene carbonate and lithium difluoro(oxalato) borate, higher concentrations of lithium salt, such as 2 M lithium salt, improve the cycle life compared to 1.3 M LiPF6 present in the electrolyte.

[0078] The electrolyte may be a solid ceramic electrolyte.

[0079] When a cell or battery containing the electrolyte provided herein is cycled at approximately 2.5V to approximately 4.3V or higher, optionally approximately 2.5V to approximately 4.65V, and optionally above approximately 4.3V, the cell optionally retains about 60% or more of its initial capacity after 100 cycles. In some embodiments, the capacity retention rate after 100 cycles is 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%, and optionally 90% or higher. In all of the above cases, the electrolyte does not undergo a shuttling reaction of its own accord.

[0080] In any of the embodiments described herein, the electrochemical cell comprising an anode, cathode, and electrolyte provided herein has a conversion voltage (FV) greater than approximately 4.3V. In any of the embodiments described herein, the electrochemical cell comprising an anode, cathode, and electrolyte provided herein has a charging voltage (CV) greater than approximately 4.3V.

[0081] The electrochemical cell can have any suitable configuration or shape, and may be cylindrical or prismatic.

[0082] Various aspects of this disclosure are illustrated below by non-limiting embodiments. These embodiments are illustrative and do not limit any implementation of the invention. It will be understood that changes and modifications can be made without departing from the spirit and scope of the invention.

[0083] Examples Example 1: Comparative Example 1: I purchased a lithium iron phosphate (LiFePO4) cathode (Targray) and tested it as is.

[0084] Example 2: Comparative Example 2: High Mn Li 1.2 Ni 0.40 Mn 0.56 Co 0.04 Preparation of O2 cathode. Ni 0.40 Mn 0.56 Co 0.04 The precursor material having the composition (OH)2 was first prepared by dissolving 4.2 kg of NiSO4·6H2O, 449 g of CoSO4·7H2O, and 3.7 kg of MnSO4·7H2O (all available from Barentz) in 17.2 liters of DI water to produce a 2 M mixed metal nitrate solution. A charge solution containing 1.8 L of DI water, 180 g of NaSO4 (Barentz), and 30 ml of NH3OH (14 M) (Barentz) was added to a 3 L reaction vessel and stirred until the temperature reached 60°C. At this point, the metal nitrate solution (approximately 4 ml / min) was added to the reactor along with NH3OH (14 M, approximately 0.2 ml / min) and NaOH (10 M, approximately 2 ml / min). The solution was stirred at 900 rpm using an overhead stirrer, and the pH was maintained at approximately 11.4 and NH3OH = 0.31 M throughout the reaction. 0.40 Mn 0.56 Co 0.04 The product slurry containing (OH)2 was continuously pumped out of a 3 L reactor to maintain a constant reactor volume. The solution was filtered, placed in an alumina crucible, and dried overnight at 120°C.

[0085] High Mn layered cathode Li1.2 Ni 0.40 Mn 0.56 Co 0.04 For the synthesis of O2, 22.23 g of LiOH (dehydrated and pulverized) and 71.13 g of Ni 0.40 Mn 0.56 Co 0.04 (OH)2 (our own product) was added to a 500 ml jar and shaken. The mixture was placed in an alumina crucible and sintered. Sintering was carried out by heating at a rate of approximately 5°C per minute to approximately 450°C and holding at 450°C for approximately 2 hours. Then, the temperature was increased by approximately 2°C increments up to approximately 850°C and held for approximately 12 hours while purging with oxygen. The sample was then allowed to cool naturally. The cooled sample was sieved, and Li 1.15 Ni 0.40 Mn 0.56 Co 0.04 O2 was obtained. The obtained sample was sieved and then tested in a coin cell.

[0086] Example 2: High-Mn Li with grain boundaries enriched with Co and Al 1.2 Ni 0.40 Mn 0.56 Co 0.04 Preparation of O2 cathode.

[0087] 2.43 grams (g) of cobalt nitrate (Co(NO3)2·6H2O), 0.5 g of aluminum nitrate (Al(NO3)3·9H2O), and 0.83 g of LiNO3 were dissolved in 20 ml of methanol (in a flat-bottom flask equipped with a magnetic stirrer) heated to 40°C, and 20 g of LiNO3 from Comparative Example 2 was added. 1.2 Ni 0.40 Mn 0.56 Co 0.04 O2 was added to it. The flask was mounted on a rotary evaporator equipped with a water bath at 40°C to 50°C. The sample was vacuumed to remove methanol. The resulting dry powder was placed in an alumina crucible and heated at a rate of 5°C per minute to approximately 450°C, and held at approximately 450°C for approximately 1 hour. The temperature was then increased at a rate of approximately 2°C per minute to approximately 700°C, and held for approximately 2 hours. The sample was then allowed to cool naturally to room temperature, and the overall composition Li 1.2 Ni 0.38 Mn 0.53 Co0.08 Al 0.01 A material containing O2 was obtained.

[0088] Cathode electrodes using a 94:3:3 composition of the materials from Example 2 and Comparative Examples 1 and 2 (active substance: AB100:PVDF) were assembled into lithium-ion coin cells (size 2025) using a microporous polyolefin separator (Celgard 2325) and an electrolyte of 1M LiPF6 in 1 / 1 / 1 (volume) EC / DMC / EMC containing 1 wt% VC (Kishida Chemical Co., Ltd.) facing a graphite carbon anode (MCMB 10-28, MSE Supplies). These lithium-ion cells were subjected to long-duration 1C charge and 1C discharge cycles at 4.2V to 2.7V at 45°C. Figure 2 shows the results of these 1C / 1C cycles. As shown in Figure 2A, the LFP cathode of Comparative Example 1 showed a rapid decrease in specific energy, while the high Mn and Co grain boundary enriched material of Example 2 showed excellent initial cycle specific energy, with a decrease in specific energy of less than 10% up to 300 cycles. As shown in Figure 2B, the Mn-rich material of Comparative Example 2 showed a relatively rapid capacity decrease. However, the grain boundary-enriched high-Mn material of Example 2 showed excellent capacity retention. Table 2 shows the discharge capacities of the same electrode at various speeds, electrochemically tested in a half-cell (cycled at 2.7-4.8V at room temperature) with the materials of Example 2 and Comparative Example 2 facing Li metal.

[0089] [Table 2]

[0090] Example 3 Comparative example 3: Li 1.2 Ni 0.40 Mn 0.56 Co 0.04 Preparation of O2 Li 1.2 Ni 0.40 Mn 0.56 Co 0.04A material having an overall O2 composition was prepared using the same method as described in Comparative Example 2, except that this sample was calcined at 900°C.

[0091] Example 3: Li with grain boundaries enriched with Co and Al 1.2 Ni 0.40 Mn 0.56 Co 0.04 Preparation of O2.

[0092] Li 1.2 Ni 0.38 Mn 0.53 Co 0.08 Al 0.01 A material having an overall O2 composition was prepared in the same manner as in Example 2, except that this sample was made using the product produced in Comparative Example 3.

[0093] The material from Example 3 was analyzed by X-ray diffraction (XRD). The results are shown in Figure 3. As shown in Figure 3, the XRD peaks are consistent with the rhombohedral LiMO2 structure with an R-3M space group. The inset shows a magnified XRD pattern at 20°~27°2θ, which indicates a Li2MnO3 monoclinic structure consistent with a high Mn cathode (Haijun Yu & Haoshen Zhou, J Phys Chem Let, 2013; 4:1268-1280).

[0094] Cathode electrodes using the materials from Example 3 and Comparative Example 3 were assembled into Li-anode half-cells and cycled at room temperature at 2.8–4.8V. The results are shown in Table 3. Full cells were also constructed using graphite anodes.

[0095] [Table 3]

[0096] Example 4 Comparative example 4: Li 1.2 Ni 0.40 Mn 0.56 Co 0.04 Preparation of O2 Ni 0.40 Mn0.56 Co 0.04 A material with the overall composition of (OH)₂ was prepared using the same method as presented in Comparative Example 2, except that the pH was set to 10.9 and NH₃OH was set to 0.31 M to enhance the solubility of the metal in the supernatant. Thereby, a material similar to Comparative Example 2 but having a higher tap density was obtained.

[0097] Li 1.2 Ni 0.40 Mn 0.56 Co 0.04 A material with the overall composition of O₂ was prepared using the same method as presented in Comparative Example 2, except that this sample was calcined at 850 °C.

[0098] Example 4: Preparation of Li with grain boundaries enriched with Co and Al 1.2 Ni 0.40 Mn 0.56 Co 0.04 Preparation of O₂ Li 1.2 Ni 0.38 Mn 0.53 Co 0.08 Al 0.1 A material with the overall composition of O₂ was prepared in the same manner as in Example 2, except that 1.52 grams (g) of Co(NO₃)₂·6H₂O, 0.29 g of Al(NO₃)₃·9H₂O, and 0.23 g of LiNO₃ were mixed with the product manufactured in Comparative Example 4 of 25 g.

[0099] The cathode electrodes using the materials of Comparative Example 4 and Example 4 were subjected to full coin cell construction as in Example 2, except that an electrolyte of 1.15 M LiPF6 in 3 / 3 / 4 (volume) EC / DEC / DMC was used. In Figure 4A, the cell was first formed up to 4.65 V and cycled at 2.8 - 4.3 V in a rapid cycle test at an average 1C discharge rate. The discharge capacity of the Mn-rich material decreased rapidly, but the grain boundary enrichment of the high-Mn material resulted in excellent capacity retention. The cell in Figure 4B was first formed up to 4.65 V and cycled at 2.8 - 4.6 V or 2.8 - 4.3 V in a rapid cycle test at an average 1C discharge rate. The discharge capacity of this material cycled at 4.6 V increased by 20% with a similar capacity retention (89% vs 91% at 350 cycles) compared to the material cycled at 4.3 V.

[0100] The cathode electrodes using the materials of Example 4 and Comparative Example 4 were assembled into Li-anode half cells and cycled at 2.8 - 4.8 V at room temperature. The results are shown in Table 4. The cells were also constructed into full cells using graphite anodes.

[0101]

Table 4

[0102] Example 5 Comparative Example 5: Li 1.08 Ni 0.56 Mn 0.40 Co 0.04 Preparation of O2 Ni 0.56 Mn 0.40 Co 0.04 Materials having the overall composition of were prepared using the same method as presented in Comparative Example 2, except that the Ni / Mn ratio was changed and pH = 11.73, NH3OH = 0.24 M.

[0103] Li 1.08 Ni 0.56 Mn 0.40 Co ... 0.04 Materials having the overall composition of were prepared from 71.16 g of Ni from Comparative Example 5 0.56Mn 0.40 Co 0.04 The preparation was carried out using the same method as described in Comparative Example 2, except that (OH)2 was mixed with 20.41 g of LiOH (dried and pulverized).

[0104] Example 5: Li with grain boundaries enriched with Co and Al 1.08 Ni 0.56 Mn 0.40 Co 0.04 Preparation of O2 Li 1.08 Ni 0.54 Mn 0.39 Co 0.06 Al 0.01 A material having an overall O2 composition was prepared in the same manner as in Example 2, except that 1.51 grams (g) of cobalt nitrate (Co(NO3)2·6H2O), 0.62 g of aluminum nitrate (Al(NO3)3·9H2O), and 0.67 g of LiNO3 were mixed with 25 g of the product prepared in Comparative Example 5.

[0105] Cathode electrodes fabricated using the materials from Comparative Example 5 and Example 5 were evaluated in a full coin cell using the same procedure as in Example 2. The cell was subjected to a full cell cycle using the cell constructed as described above, and cycled with a graphite anode at 45°C and 2.7-4.2V with 1C charge / 1C discharge. The results are shown in Figure 5.

[0106] Example 6 Comparative Example 6. Li 1.03 Ni 0.61 Mn 0.35 Co 0.04 Preparation of O2 Ni 0.61 Mn 0.35 Co 0.04 A material having an overall composition of (OH)2 was prepared using the same method as presented in Comparative Example 2, except that the Ni / Mn ratio was changed to pH=11.94 and NH3OH=0.2M.

[0107] Li 1.03 Ni 0.61 Mn 0.35 Co 0.04A material having an overall O2 composition was obtained from 71.16 g of Ni from Comparative Example 6. 0.61 Mn 0.35 Co 0.04 The preparation was carried out using the same method as described in Comparative Example 2, except that (OH)2 was mixed with 19.25 g of LiOH (dried and pulverized).

[0108] Example 6 Li with grain boundaries enriched with Co and Al 1.03 Ni 0.61 Mn 0.35 Co 0.04 Preparation of O2 Li 1.03 Ni 0.57 Mn 0.34 Co 0.08 Al 0.01 A material having an overall O2 composition was prepared in the same manner as in Example 2, except that this sample was made using the product produced in Comparative Example 6.

[0109] The cathode electrodes using the materials from Comparative Example 6 and Example 6 were subjected to full coin cell construction as in Example 2, except that a 1.15 M LiPF6 electrolyte in 3 / 3 / 4 (volume) EC / DEC / DMC was used. In Figure 6, the cell was initially formed up to 4.65 V and then cycled from 2.8 to 4.3 V in a rapid cycling test at an average discharge rate of 1 C. The discharge capacity of the Mn-rich material decreased rapidly, but grain boundary enrichment of the high-Mn material resulted in excellent capacity.

[0110] Example 7. Comparative Example 7. Li 1.28 Ni 0.36 Mn 0.60 Co 0.04 Preparation of O2 Ni 0.36 Mn 0.60 Co 0.04 A material having an overall composition of (OH)2 was prepared using the same method as presented in Comparative Example 2, except that the Ni / Mn ratio was changed to pH=10.75 and NH3OH=0.25.

[0111] Li 1.28 Ni 0.36 Mn0.60 Co 0.04 A material having an overall O2 composition was obtained from 71.13 g of Ni from Comparative Example 7. 0.36 Mn 0.60 Co 0.04 The preparation was carried out using the same method as described in Comparative Example 2, except that (OH)2 was mixed with 24.53 g of LiOH (dried and pulverized).

[0112] Example 7 Li with grain boundaries enriched with Co and Al 1.28 Ni 0.36 Mn 0.60 Co 0.04 Preparation of O2 Li 1.28 Ni 0.35 Mn 0.58 Co 0.06 Al 0.01 A material having an overall O2 composition was prepared in the same manner as in Example 2, except that 1.51 grams (g) of Co(NO3)2·6H2O cobalt, 0.62 g of Al(NO3)3·9H2O, and 0.67 g of LiNO3 were mixed with 25 g of the product prepared in Comparative Example 7.

[0113] The cathode electrodes using the materials from Comparative Example 7 and Example 7 were subjected to full coin cell construction as in Example 2, except that a 1.15 M LiPF6 electrolyte in 3 / 3 / 4 (volume) EC / DEC / DMC was used. In Figure 7, the cell was initially formed up to 4.65 V and then cycled from 2.8 to 4.3 V in a rapid cycling test at an average discharge rate of 1 C. The discharge capacity of the Mn-rich material decreased rapidly, but grain boundary enrichment of the high-Mn material resulted in excellent capacity.

[0114] Example 8 . [Table 5]

[0115] Additional exemplary embodiments Embodiment 1. An electrochemical active material, Formula Li 1+a MO 2+bThe first composition comprises (Formula I) [wherein -0.3 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3, and M comprises 30 at% to 70 at% Mn and 25 at% to 70 at% Ni], wherein the first composition is formed from a polycrystalline form including a plurality of crystallites and grain boundaries between adjacent crystallites, The aforementioned grain boundary is, 1+a M'O 2+b The composition comprises a second composition of formula (II) [wherein -0.1 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3], The grain boundary contains one or more enriching elements in at least a portion thereof, the one or more enriching elements are present in the portion at a higher atomic percentage than adjacent crystallites, and the one or more enriching elements are selected from the group consisting of Co, Al, and Co and Al. Electrochemical active material.

[0116] Embodiment 2. The electrochemical active material according to Embodiment 1, wherein M contains 30 at% to 65 at% of Mn, and optionally 35 at% to 65 at% of Mn.

[0117] Embodiment 3. The electrochemical active material according to Embodiment 1 or 2, wherein the second composition has an α-NaFeO2 type structure, a cubic crystal structure, a spinel structure, or a combination thereof.

[0118] Embodiment 4. An electrochemical active material according to any one of Embodiments 1 to 3, wherein the particles have a particle size of about 1 μm to about 25 μm.

[0119] Embodiment 5. An electrochemical active material according to any one of Embodiments 1 to 4, wherein each of the crystallites independently has a particle size of less than approximately 1 μm.

[0120] Embodiment 6. An electrochemical active material according to any one of Embodiments 1 to 5, wherein the enriching element contains Co.

[0121] Embodiment 7. An electrochemical active material according to any one of Embodiments 1 to 6, wherein M further comprises Co.

[0122] Embodiment 8. An electrochemical active material according to Embodiment 7, wherein Co is present in an amount greater than approximately 0 at% to approximately 15 at%, and arbitrarily between approximately 0.01 at% and approximately 10 at%.

[0123] Embodiment 9. An electrochemical active material according to Embodiment 7 or 8, wherein M comprises about 30 at% to about 70 at% of Mn, about 25 at% to about 70 at% of Ni, greater than 0 to about 15 at% of Co and / or 0 to about 5 at% of Mg, or any combination thereof.

[0124] Embodiment 10. An electrochemical active material according to any one of Embodiments 1 to 9, wherein M contains about 30 at% to about 65 at% of Mn, about 25 at% to about 70 at% of Ni, more than 0 to about 15 at% of Co, and about 0 at% to about 5 at% of Mg.

[0125] Embodiment 11. An electrochemical active material according to any one of Embodiments 1 to 10, wherein the enriching element is Al, or both Co and Al.

[0126] Embodiment 12. An electrochemical active material according to any one of Embodiments 1 to 11, wherein Mn is present in the first composition in an amount of about 45 at% to about 65 at%.

[0127] Embodiment 13. An electrochemical active material according to any one of Embodiments 1 to 12, comprising Ni in an amount of 40 at% or less of M.

[0128] Embodiment 14. An electrochemical active material according to any one of Embodiments 1 to 13, wherein M comprises about 25 at% to about 70 at% Ni, about 0 to 15 at% Co, about 30 at% to about 65 at% Mn and 0 to 10 at% of additional elements.

[0129] Embodiment 15. An electrochemical active material according to any one of Embodiments 1 to 14, wherein the grain boundary contains the enriching element at an atomic percentage higher than the average atomic percentage of the enriching element in adjacent crystallites.

[0130] Embodiment 16. An electrochemical active material according to any one of Embodiments 1 to 15, wherein M' is present in an amount of 30 at% to 70 at% relative to the total amount of M'.

[0131] Embodiment 17. The electrochemical active material according to Embodiment 16, wherein M' contains approximately 10 atomic percent to approximately 70 atomic percent (at%) of Ni in total M'.

[0132] Embodiment 18. An electrode comprising an electrochemical active material according to any one of Embodiments 1 to 17, and further comprising a current collector in electrical contact with the particles or a plurality of particles.

[0133] Embodiment 19. An electrochemical cell comprising a first electrode, which is the electrode described in Embodiment 18, and a second electrode.

[0134] Embodiment 20. The electrochemical cell according to Embodiment 19, wherein the second electrode comprises carbon or lithium titanate.

[0135] Embodiment 21. The electrochemical cell according to Embodiment 20, wherein the carbon comprises graphite.

[0136] Embodiment 22. When the electrochemical cell is equipped with a graphite anode, (approximately 2 mAh / cm²) 2 An electrochemical cell according to any one of embodiments 19 to 21, characterized by a discharge capacity of more than 140 mAh / g, which can be maintained for more than 400 cycles, and optionally more than 160 mAh / g, which can be maintained for more than 400 cycles, when cycled using a cathode load at 45°C, 2.7 to 4.2 V, and an average C rate > 1.

[0137] Embodiment 23. When the electrochemical cell is equipped with a graphite anode, (approximately 2 mAh / cm²) 2An electrochemical cell according to any one of embodiments 19 to 21, characterized by a discharge capacity of more than 140 mAh / g, which can be maintained for more than 400 cycles, and optionally more than 200 mAh / g, which can be maintained for more than 400 cycles, when cycled using a cathode load at 45°C, 2.7 to 4.6 V, and an average C rate > 1.

[0138] Embodiment 24. An electrochemical cell comprising a cathode containing an electrochemical active material according to any one of Embodiments 1 to 17, an anode, and an electrolyte that does not contain ethylene carbonate.

[0139] Embodiment 25. The electrochemical cell according to Embodiment 24, wherein the anode comprises carbon or lithium titanate.

[0140] Embodiment 26. The electrochemical cell according to Embodiment 25, wherein the anode contains carbon.

[0141] Embodiment 27. An electrochemical cell according to any one of Embodiments 24 to 26, wherein the electrolyte comprises a lithium salt and dimethyl carbonate alone or in combination with one or more additives.

[0142] Embodiment 28. An electrochemical cell according to Embodiment 27, wherein the additive 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 cosolvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some embodiments, the additive optionally includes fluoroethylene carbonate, difluoroethylene carbonate, lithium difluoro(oxalato)borate, or a combination thereof.

[0143] While this disclosure describes exemplary embodiments, those skilled in the art will understand that various modifications can be made without departing from the scope of the disclosed embodiments, and that elements can be replaced with equivalents. In addition, many modifications can be made without departing from the scope of this disclosure to adapt specific circumstances or materials to the teachings of this disclosure. Accordingly, this disclosure is not intended to be limited to any particular embodiment disclosed as the best form considered for carrying out this disclosure. It should also be understood that the embodiments disclosed herein are not intended to be limiting and should be considered only in a descriptive sense. The descriptions of features or aspects of each embodiment should be considered applicable to other similar features or aspects of other embodiments.

[0144] When one element is described as being "on top of" another, it can mean that it is directly on top of the other, or that there is an intervening element between them. In contrast, when one element is described as being "directly on top of" another, there is no intervening element.

[0145] Terms such as “first,” “second,” and “third” may be used herein to describe various elements, components, regions, layers, and / or parts, but it will be understood that these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used solely to distinguish one element, component, region, layer, or part from another. For this reason, “first element,” “component,” “region,” “layer,” or “part” discussed below may be referred to as the second element, component, region, layer, or part without departing from the teachings of this specification.

[0146] The technical terms used herein are intended solely to describe specific embodiments and are not intended to limit them. Where used herein, the singular forms “a,” “an,” and “the” are intended to include the plural form, which includes “at least one,” unless the context clearly indicates otherwise. “Or” means “and / or.” Where used herein, the term “and / or” includes any combination of one or more of the enumerated items relating to the description. Where used herein, “comprises” and / or “comprising” or “includes” and / or “including” specify the presence of the described features, regions, integers, processes, operations, elements, and / or components, but it will be further understood that they do not exclude the presence or addition of one or more other features, regions, integers, processes, operations, elements, components, and / or groups thereof. The term “or combination thereof” means a combination that includes at least one of the elements described above.

[0147] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as generally understood by those skilled in the art to the extent of this disclosure. Terms as defined in commonly used dictionaries should be construed to have the meaning consistent with their meanings in the relevant technical field and in the context of this disclosure, and it will be further understood that they should not be construed in an idealized or overly formal sense unless expressly defined herein.

[0148] All at% concentrations given herein, whether expressly stated otherwise or not, are considered approximate to the listed concentrations, and optionally, “approximate” includes values ​​equivalent to and / or within experimental error. In some embodiments, where optionally desired, all or part of the at% concentrations are the listed values ​​or ranges themselves.

[0149] In addition to those shown and described herein, various modifications of the present invention will be apparent to those skilled in the art of the art. Such modifications are also intended to be included in the appended claims.

[0150] Unless otherwise specified, all reagents are understood to be available from known sources in the art. Methods for nucleotide amplification, cell transfection, and protein expression and purification are also within the realm of the art for those skilled in the art.

[0151] The patents, publications, and applications referenced herein represent the state of the art for those skilled in the art to which the present invention pertains. These patents, publications, and applications are incorporated herein by reference to the same extent as individual patents, publications, or applications are incorporated herein by reference specifically and individually.

[0152] List of References Y. Ikuhara, “Atomic-scale observations of (010) LiFePO4surface before and after chemical delithiation” Nano Lett. 2016, 16, 5409-5414 Haijun Yu & Haoshen Zhou, “High-Energy cathode materials (Li2MnO3-LiMO2) for lithium-ion batteries”J Phys Chem Let 2013, 4, 1268-1280 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. It is an electrochemical active material, Formula Li １＋ａ MO ２＋ｂ The first composition comprises (Formula I) [wherein -0.3 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3, and M comprises 30 at% to 70 at% Mn and 25 at% to 70 at% Ni], wherein the first composition is formed from a polycrystalline form including a plurality of crystallites and grain boundaries between adjacent crystallites, The aforementioned grain boundary, formula Li １＋ａ M'O ２＋ｂ (Formula II) [wherein -0.1 ≤ a ≤ 1.3 and -0.3 ≤ b ≤ 1.3] comprises a second composition, The grain boundary contains one or more enriching elements in at least a portion thereof, the one or more enriching elements are present in the portion at a higher atomic percentage than in adjacent crystallites, and the one or more enriching elements include Co, Al, or both Co and Al. Electrochemical active material.

2. The electrochemical active material according to claim 1, wherein M contains 30 at% to 65 at% Mn.

3. The second composition is α-NaFeO ２ The electrochemical active material according to claim 1, having a cubic structure, a spinel structure, or a combination thereof.

4. The electrochemical active material according to claim 1, which is in the form of secondary particles having a particle size of approximately 1 μm to approximately 25 μm.

5. The electrochemical active material according to claim 1, wherein each of the crystallites independently has a particle size of less than about 1 μm.

6. The electrochemical active material according to claim 1, wherein the enriching element includes Co.

7. The electrochemical active material according to claim 1, wherein M further comprises Co.

8. The electrochemical active material according to claim 7, wherein Co is present in an amount of more than approximately 0 at% to approximately 15 at%, and optionally from approximately 0.01 at% to approximately 10 at%.

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

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

11. The electrochemical active material according to any one of claims 1 to 9, wherein the enriching element is Al, or both Co and Al.

12. The electrochemical active material according to any one of claims 1 to 9, wherein Mn is present in the first composition in an amount of about 45 at% to about 65 at%.

13. An electrochemical active material according to any one of claims 1 to 9, comprising Ni with an M content of 40 at% or less.

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

15. The electrochemical active material according to any one of claims 1 to 9, wherein the grain boundary contains the enriching element at an atomic percentage higher than the average atomic percentage of the enriching element in adjacent crystallites.

16. The electrochemical active material according to claim 1, wherein M' contains 10 at% to 70 at% of Mn relative to the total M', and optionally 30 at% to 65 at% of Mn relative to the total M'.

17. The electrochemical active material according to claim 15, wherein M' contains Ni in an amount of about 10 atomic percent to about 70 atomic percent (at%) of the total M'.

18. An electrode comprising an electrochemical active material according to any one of claims 1 to 9, and further comprising a current collector in electrical contact with the electrochemical active material.

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

20. The electrochemical cell according to claim 19, wherein the second electrode comprises carbon or lithium titanate.

21. The electrochemical cell according to claim 20, wherein the carbon comprises graphite.

22. If the electrochemical cell is equipped with a graphite anode, (approximately 2 mAh / cm²) ２ The electrochemical cell according to claim 19, characterized by a discharge capacity of more than 140 mAh / g that can be maintained for 400 cycles or more, and optionally more than 160 mAh / g that can be maintained for 400 cycles or more, when cycled using a cathode load at 45°C, 2.7 to 4.2 V, and average C rate > 1.

23. If the electrochemical cell is equipped with a graphite anode, (approximately 2 mAh / cm²) ２ The electrochemical cell according to claim 19, characterized by a discharge capacity of more than 140 mAh / g that can be maintained for 400 cycles or more, and optionally more than 200 mAh / g that can be maintained for 400 cycles or more, when cycled using a cathode load at 45°C, 2.7 to 4.6 V, and average C rate > 1.

24. An electrochemical cell comprising a cathode containing an electrochemical active material according to any one of claims 1 to 9, an anode, and an electrolyte that does not contain ethylene carbonate.

25. The electrochemical cell according to claim 24, wherein the anode comprises carbon or lithium titanate.

26. The electrochemical cell according to claim 25, wherein the anode contains carbon.

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

28. The aforementioned additives include fluoroethylene carbonate (FEC), difluoroethylene carbonate (F2EC), tris(trimethylsilyl) malonate (TMSM), tris(trimethylsilyl) phosphite (TMSPi), and tris(trimethylsilyl) phosphate (TMSPO). ４ The electrochemical cell according to claim 27, comprising ), lithium bis(oxalato)borate (LiDFOB) and cosolvent 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TFETFPE). In some embodiments, the additive optionally includes fluoroethylene carbonate, difluoroethylene carbonate, lithium difluoro(oxalato) borate, or a combination thereof.

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

30. The electrochemical active materials provided herein.

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