Positive electrode comprising oxygen storage material

Abstract

The present invention provides a positive electrode for a battery circulating lithium ions, comprising an electroactive material and an electrochemically inert oxygen storage material (OSM). The electroactive material comprises a lithium transition metal oxide (LiTMO) formulated for reversible intercalation of lithium ions. The OSM is configured to store oxygen released from the LiTMO.

Description

Technical Field

[0001] The present disclosure relates to positive electrodes for cycling lithium-ion batteries, and more particularly to positive electrodes containing oxygen storage materials. Background Art

[0002] The information provided in this section is intended to generally introduce the background of the present disclosure. To the extent that the operations currently named as inventors are described in this section, and aspects of the specification that may not have been otherwise identified as prior art at the time of filing, are not admitted, either explicitly or implicitly, as prior art against the present disclosure.

[0003] The present disclosure relates to positive electrodes for cycling lithium-ion batteries, and more particularly to positive electrodes containing oxygen storage materials.

[0004] A battery pack that cycles lithium ions typically includes a negative electrode, a positive electrode, and an electrolyte that provides a medium for lithium ion conduction between the negative electrode and the positive electrode. Heat is often generated during battery operation and may accumulate in the battery pack during prolonged operation and / or under abuse conditions. The accumulated heat may trigger additional exothermic chemical reactions between the components of the battery pack, which may reduce the electrochemical performance of the battery pack and may cause thermal runaway. For example, a layered lithium transition metal oxide (LiTMO) positive electrode material may thermally decompose and release oxygen when heated during battery operation, and the oxygen may react exothermically with the electrolyte, thereby generating additional heat in the battery pack. In addition, the LiTMO positive electrode material may undergo an irreversible phase change during thermal decomposition, and may, for example, transform from a layered structure to a spinel structure, and may transform into a rock salt structure, resulting in irreversible capacity decay.

[0005] Nickel (Ni)-rich LiTMO positive electrode materials have relatively high capacity and relatively low cost compared to other LiTMO positive electrode materials. However, as the nickel content of such materials increases, their cycling stability, rate capability, and thermal stability have been found to decrease. One proposed mechanism for the observed performance degradation is that in the highly delithiated (i.e., charged) state, Ni 4+ May be reduced to Ni 2+ , resulting in the concomitant release of oxygen and the generation of additional heat within the battery. It would be desirable to improve the thermal stability of the LiTMO positive electrode material, for example by inhibiting or counteracting oxygen release therefrom. Summary of the invention

[0006] Disclosed is a positive electrode for a battery pack for cycling lithium ions. According to one or more aspects of the present disclosure, the positive electrode comprises an electroactive material and an electrochemically inert oxygen storage material (OSM). The electroactive material comprises a lithium transition metal oxide (LiTMO) formulated to reversibly intercalate lithium ions. The electrochemically inert OSM is formulated to store oxygen released from the LiTMO.

[0007] LiTMO may include a nickel-rich lithium transition metal oxide (Ni-rich LiTMO) represented by the formula Li 1+a Ni x Me y O2, where Me is a transition metal, 0 ≤ a ≤ 1, 0.5 < x ≤ 1, 0 ≤ y < 0.5, and x + y = about 1. In some aspects, Me may be a transition metal selected from cobalt (Co), manganese (Mn), aluminum (Al), and combinations thereof.

[0008] The Ni-rich LiTMO may include Li a Ni x Co y Mn 1-x-y O2 (NCM), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; Li a Ni x Co y Al 1-x-y O2 (NCA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; (Li a Ni x Co y Mn z Al 1-x-y-z O2 (NCMA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, 0 < y < 0.4, and 0 < z < 0.4), LiNiO2 (LNO), or a combination thereof.

[0009] LiTMO may include a layered lithium-rich transition metal oxide represented by the formula Li 1+x Me 1-x O2, where 0 < x ≤ 0.5 and Me is a transition metal.

[0010] LiTMO may constitute greater than or equal to about 80% and less than or equal to about 95% of the positive electrode by weight.

[0011] The OSM may include a monometallic oxide, a mixed metal oxide, a solid solution of a monometallic oxide or a mixed metal oxide, or a combination thereof.

[0012] The OSM may include oxides of cerium (Ce), manganese (Mn), zirconium (Zr), gadolinium (Gd), samarium (Sm), copper (Cu), titanium (Ti), calcium (Ca), lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), aluminum (Al), praseodymium (Pr), neodymium (Nd), promethium (Pm), nickel (Ni), manganese (Mn), beryllium (Be), yttrium (Y), or combinations thereof.

[0013] The OSM may comprise a composite of (i) a monometallic oxide or a mixed metal oxide and (ii) a metal nitride, a metal carbide, a metal boride, or combinations thereof.

[0014] The OSM may have a lattice structure and may be formulated to store oxygen in its lattice structure. The OSM may have an oxygen storage capacity of greater than or equal to about 400 micromoles of oxygen / gram.

[0015] The OSM may be doped with lithium.

[0016] The OSM may constitute greater than or equal to about 1% and less than or equal to about 10% of the positive electrode by weight.

[0017] The positive electrode may further comprise an electrochemically inert solid lithium conducting material, which includes lithium oxide, lithium phosphosulfide, lithium phosphate, or combinations thereof. The electrochemically inert solid lithium conducting material may be in physical contact with the OSM.

[0018] The positive electrode may further comprise a polymeric binder and a conductive material. The polymeric binder and the conductive material may each be present in the positive electrode in an amount greater than or equal to about 0.5% and less than or equal to about 30% by weight of the positive electrode.

[0019] According to one or more aspects of the present disclosure, a positive electrode of a battery pack for cycling lithium ions comprises an electroactive material and an electrochemically inert oxygen storage material (OSM). The electroactive material comprises a lithium transition metal oxide (LiTMO) formulated to undergo reversible intercalation of lithium ions. The LiTMO includes at least one of the following: (i) a nickel-rich lithium transition metal oxide (Ni-rich LiTMO) represented by the formula Li 1+a Ni x Me y O2, where Me is a transition metal, 0 ≤ a ≤ 1, 0.5 < x ≤ 1, 0 ≤ y < 0.5, and x + y = about 1, or (ii) a layered lithium-rich transition metal oxide represented by the formula Li 1+x Me 1-x O2, where 0 < x ≤ 0.5 and Me is a transition metal. The electrochemically inert OSM is formulated to store oxygen released from the LiTMO.

[0020] Me can be a transition metal selected from cobalt (Co), manganese (Mn), aluminum (Al), and combinations thereof.

[0021] LiTMO can include Ni-rich LiTMO. In this case, the Ni-rich LiTMO can include Li a Ni x Co y Mn 1-x-y O 2( NCM), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; Li a Ni x Co y Al 1-x-y O2 (NCA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; (Li a Ni x Co y Mn z Al 1-x-y-z O2 (NCMA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, 0 < y < 0.4, and 0 < z < 0.4), LiNiO2 (LNO), or a combination thereof.

[0022] LiTMO can constitute greater than or equal to about 80% and less than or equal to about 95% of the positive electrode by weight.

[0023] OSM can include oxides of cerium (Ce), manganese (Mn), zirconium (Zr), gadolinium (Gd), samarium (Sm), copper (Cu), titanium (Ti), calcium (Ca), lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), aluminum (Al), praseodymium (Pr), neodymium (Nd), promethium (Pm), nickel (Ni), manganese (Mn), beryllium (Be), yttrium (Y), or combinations thereof.

[0024] The weight ratio of OSM to LiTMO can be greater than or equal to about 1:99 and less than or equal to about 1:9.

[0025] The present invention discloses the following solutions:

[0026] Solution 1. A positive electrode for a battery pack for cycling lithium ions, the positive electrode comprising:

[0027] An electroactive material comprising a lithium transition metal oxide (LiTMO) formulated to reversibly intercalate lithium ions; and

[0028] An electrochemically inert oxygen storage material (OSM) formulated to store oxygen released from LiTMO.

[0029] Solution 2. The positive electrode according to Solution 1, wherein the LiTMO includes the formula Li1+a Ni x Me y A nickel-rich lithium transition metal oxide (Ni-rich LiTMO) represented by O2,

[0030] where Me is a transition metal, 0 ≤ a ≤ 1, 0.5 < x ≤ 1, 0 ≤ y < 0.5, and x + y = approximately 1.

[0031] Aspect 3. The positive electrode according to Aspect 2, wherein Me is a transition metal selected from cobalt (Co), manganese (Mn), aluminum (Al), and combinations thereof.

[0032] Aspect 4. The positive electrode according to Aspect 2, wherein the Ni-rich LiTMO comprises Li a Ni x Co y Mn 1-x-y O2 (NCM), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; Li a Ni x Co y Al 1-x-y O2 (NCA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; (Li a Ni x Co y Mn z Al 1-x-y-z O2 (NCMA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, 0 < y < 0.4, and 0 < z < 0.4), LiNiO2 (LNO), or a combination thereof.

[0033] Aspect 5. The positive electrode according to Aspect 1, wherein the LiTMO comprises a layered lithium-rich transition metal oxide represented by the formula Li 1+x Me 1-x O2, where 0 < x ≤ 0.5 and Me is a transition metal.

[0034] Aspect 6. The positive electrode according to Aspect 1, wherein the LiTMO constitutes greater than or equal to approximately 80% and less than or equal to approximately 95% of the positive electrode by weight.

[0035] Aspect 7. The positive electrode according to Aspect 1, wherein the OSM comprises a monometallic oxide, a mixed metal oxide, a solid solution of a monometallic oxide or a mixed metal oxide, or a combination thereof.

[0036] Option 8. A positive electrode according to Option 1, wherein the OSM includes oxides of cerium (Ce), manganese (Mn), zirconium (Zr), gadolinium (Gd), samarium (Sm), copper (Cu), titanium (Ti), calcium (Ca), lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), aluminum (Al), praseodymium (Pr), neodymium (Nd), promethium (Pm), nickel (Ni), manganese (Mn), beryllium (Be), yttrium (Y) or combinations thereof.

[0037] Option 9. The positive electrode according to Option 1, wherein the OSM comprises a composite of (i) a monometallic oxide or a mixed metal oxide and (ii) a metal nitride, a metal carbide, a metal boride or a combination thereof.

[0038] Embodiment 10. A positive electrode according to Embodiment 1, wherein the OSM has a lattice structure and is configured to store oxygen in its lattice structure, and wherein the OSM has an oxygen storage capacity greater than or equal to about 400 micromoles of oxygen / gram.

[0039] Embodiment 11. The positive electrode according to Embodiment 1, wherein the OSM is doped with lithium.

[0040] Embodiment 12. The positive electrode of Embodiment 1, wherein the OSM constitutes greater than or equal to about 1% and less than or equal to about 10% by weight of the positive electrode.

[0041] Option 13. According to Option 1, the positive electrode further comprises an electrochemically inert solid lithium conductive material, wherein the electrochemically inert solid lithium conductive material comprises lithium oxide, lithium phosphosulfide, lithium phosphate or a combination thereof, wherein the electrochemically inert solid lithium conductive material is in physical contact with the OSM.

[0042] Option 14. The positive electrode according to Option 1 also comprises a polymer binder and a conductive material, wherein the polymer binder and the conductive material are each present in the positive electrode in an amount greater than or equal to about 0.5% and less than or equal to about 30% by weight of the positive electrode.

[0043] Scheme 15. A positive electrode for a battery pack for cycling lithium ions, the positive electrode comprising:

[0044] An electroactive material comprising a lithium transition metal oxide (LiTMO) formulated for reversible intercalation of lithium ions, the LiTMO comprising at least one of:

[0045] (i) From the formula Li 1+a Ni x Me yA nickel-rich lithium transition metal oxide (Ni-rich LiTMO) represented by O2, where Me is a transition metal, 0 ≤ a ≤ 1, 0.5 < x ≤ 1, 0 ≤ y < 0.5, and x + y = approximately 1; or

[0046] (ii) A layered lithium-rich transition metal oxide represented by the formula Li 1+x Me 1-x O2, where 0 < x ≤ 0.5 and Me is a transition metal; and

[0047] An electrochemically inert oxygen storage material (OSM) that is formulated to store oxygen released from LiTMO.

[0048] Aspect 16. The positive electrode according to aspect 15, wherein Me is a transition metal selected from cobalt (Co), manganese (Mn), aluminum (Al), and combinations thereof.

[0049] Aspect 17. The positive electrode according to aspect 15, wherein the LiTMO includes a Ni-rich LiTMO, and wherein the Ni-rich LiTMO includes Li a Ni x Co y Mn 1-x-y O2 (NCM), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; Li a Ni x Co y Al 1-x-y O2 (NCA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4; (Li a Ni x Co y Mn z Al 1-x-y-z O2 (NCMA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, 0 < y < 0.4, and 0 < z < 0.4), LiNiO2 (LNO), or a combination thereof.

[0050] Aspect 18. The positive electrode according to aspect 15, wherein the LiTMO constitutes greater than or equal to approximately 80% and less than or equal to approximately 95% of the positive electrode by weight.

[0051] Aspect 19. The positive electrode according to aspect 15, wherein the OSM includes oxides of cerium (Ce), manganese (Mn), zirconium (Zr), gadolinium (Gd), samarium (Sm), copper (Cu), titanium (Ti), calcium (Ca), lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), aluminum (Al), praseodymium (Pr), neodymium (Nd), promethium (Pm), nickel (Ni), manganese (Mn), beryllium (Be), yttrium (Y), or combinations thereof.

[0052] Embodiment 20. The positive electrode according to embodiment 15, wherein the weight ratio of the OSM to the LiTMO is greater than or equal to about 1:99 and less than or equal to about 1:9.

[0053] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended to be illustrative only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present disclosure will be more fully understood through the detailed description and accompanying drawings, in which:

[0055] Figure 1 is a schematic perspective view of a motor vehicle powered by a battery pack including a plurality of battery modules.

[0056] Figure 2 yes Figure 1 A schematic cross-sectional view of a portion of one of a battery module including a plurality of cycling lithium-ion electrochemical cells or batteries.

[0057] Figure 3 is a schematic cross-sectional view of a cycling lithium ion battery including a positive electrode, a negative electrode, a porous separator, and an electrolyte that permeates the pores of the positive and negative electrodes and the porous separator.

[0058] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0059] The positive electrode of the present disclosure is formulated for a battery pack for cycling lithium ions and comprises a lithium transition metal oxide (LiTMO) electroactive material and an oxygen storage material (OSM). The OSM is formulated to act as an "oxygen buffer" by reversibly storing and releasing oxygen during the operation of the battery pack. For example, the OSM can remove oxygen released from the LiTMO electroactive material of the positive electrode during high temperature operation of the battery pack and / or during the delithiation process of the LiTMO electroactive material (i.e., during the charging process of the battery pack). By storing the oxygen generated in the positive electrode during the operation of the battery pack, the OSM can help prevent or inhibit the released oxygen from exothermically reacting with the electrolyte and generating heat, which can improve the thermal stability of the battery pack. In addition, the OSM can provide a readily available oxygen source to the LiTMO electroactive material of the positive electrode during the discharge process of the battery pack, which can help to improve the reversibility of the phase change that occurs in the LiTMO electroactive material during the cycling process of the battery pack. By providing an oxygen source to the LiTMO electroactive material of the positive electrode during the operation of the battery pack, the OSM can help improve the capacity retention and cycle stability of the battery pack. It has been found that a positive electrode comprising the disclosed LiTMO electroactive material and an OSM generates less heat and exhibits substantially the same capacity over time as a positive electrode comprising the same LiTMO electroactive material without an OSM.

[0060] Figure 1 A motor vehicle 2 is depicted that is powered by an electric motor 4 that draws power from a battery pack 6 that includes one or more battery modules 8. The battery modules 8 may be electrically coupled together in a series and / or parallel arrangement to meet the desired capacity and power requirements of the electric motor 4. The vehicle 2 may be an all-electric vehicle and may be powered solely by the electric motor 4, or the vehicle 2 may be a hybrid electric vehicle and may be powered by both the electric motor 4 and an internal combustion engine (not shown).

[0061] like Figure 2 As shown in , each battery module 8 includes one or more electrochemical cells or batteries 10 that circulate lithium ions. In practice, the batteries 10 in the battery module 8 are typically assembled as a stack of layers, including a negative electrode layer 12, a negative electrode current collector 13, a positive electrode layer 14, a positive electrode current collector 15, and a separator layer 16. Each battery 10 is defined by a negative electrode layer 12 and a positive electrode layer 14 separated from each other by a separator layer 16. The negative electrode layer 12 is disposed on the negative electrode current collector 13 and is electrically connected to the negative electrode current collector 13, and the positive electrode layer 14 is disposed on the positive electrode current collector 15 and is electrically connected to the positive electrode current collector 15. As shown in Figure 2As shown in , for efficiency, these layers can be stacked so that some of the negative electrode collectors 13 and the positive electrode collectors 15 are double-sided and include negative electrode layers 12 or positive electrode layers 14 on both sides thereof. In this arrangement, adjacent negative electrode layers 12 and positive electrode layers 14 share a single negative current collector 13 or positive current collector 15.

[0062] Figure 3 An electrochemical cell or battery 20 of circulating lithium ions is depicted. The battery 20 can generate an electric current during discharge, which can be used to power a load device (e.g., the motor 4), and can be recharged by connecting to a power source. Figure 1 and Figure 2 , in some aspects, the battery pack 20 can be used to power the electric motor 4 of the motor vehicle 2. Additionally or alternatively, the battery pack 20 can be used in other transportation applications (e.g., motorcycles, boats, tractors, buses, motorbikes, mobile homes, campers, tanks, and aircraft), and can be used to provide power to fixed and / or portable electronic devices, components, and devices used in various other industries and applications, including, as non-limiting examples, industrial, residential and commercial buildings, consumer products, industrial equipment and machinery, agricultural or farm equipment, and heavy machinery.

[0063] The battery 20 includes a negative electrode 22, a positive electrode 24, and an electrolyte 28, which wets the surfaces of the negative electrode 22, the positive electrode 24, and the separator 26. The negative electrode 22 is disposed on a negative electrode current collector 30 and the positive electrode 24 is disposed on a positive electrode current collector 32. In practice, the negative electrode current collector 30 and the positive electrode current collector 32 are electrically coupled to a power source or load 34 (e.g., the motor 12) via an external circuit 36. The negative electrode 22 and the positive electrode 24 are configured so that when the battery 20 is at least partially charged, an electrochemical potential difference is established between the negative electrode 22 and the positive electrode 24. During the discharge process of the battery 20, the electrochemical potential established between the negative electrode 22 and the positive electrode 24 drives the spontaneous reduction and oxidation (redox) reactions within the battery 20 and the release of lithium ions and electrons at the negative electrode 22. The released lithium ions move from the negative electrode 22 to the positive electrode 24 through the separator 26 and the electrolyte 28, while the electrons move from the negative electrode 22 to the positive electrode 24 through the external circuit 36, thereby generating an electric current. After the negative electrode 22 has been partially or completely depleted of lithium, the battery 20 can be charged by connecting the negative electrode 22 and the positive electrode 24 to the power source 34, which drives a non-spontaneous redox reaction within the battery 20 and releases lithium ions and electrons from the positive electrode 24. Repeated discharge and charging of the battery 20 may be referred to herein as a "cycle," where a full discharge event followed by a full charge event is considered a complete cycle.

[0064] Positive electrode 24 comprises an electrochemically active (electroactive) material, an electrochemically inert oxygen storage material (OSM), and optionally an electrochemically inert solid lithium conductive material.

[0065] The electroactive material of the positive electrode 24 is formulated to reversibly store and release lithium ions by undergoing a reversible redox reaction with lithium during the discharge and charge processes of the battery 20. The electroactive material of the positive electrode 24 includes at least one transition metal ion that participates in the electrochemical reactions responsible for the operation of the battery 20. During the discharge process of the battery 20, the electroactive transition metal ions in the electroactive material of the positive electrode 24 are reduced and the lithium ions are intercalated or inserted into the crystal structure of the electroactive material of the positive electrode 24. During the charge process of the battery 20, the electroactive transition metal in the electroactive material of the positive electrode 24 is oxidized and the lithium ions are deintercalated and extracted from the crystal structure of the electroactive material of the positive electrode 24.

[0066] The electroactive material of the positive electrode 24 includes a lithium transition metal oxide (LiTMO) capable of reversible insertion or intercalation of lithium ions. The LiTMO electroactive material of the positive electrode 24 may include a layered oxide represented by the formula LiMeO2 and / or Li2MeO3, a layered oxide represented by the formula Li 1+x Me 1-x O2 (where 0 < x ≤ 0.5), an olivine-type oxide represented by the formula LiMePO4, a monoclinic oxide represented by the formula Li3Me2(PO4)3, a spinel-type oxide represented by the formula LiMe2O4, a tavorite represented by one or both of the following formulas LiMeSO4F or LiMePO4F, or a combination thereof, wherein Me is a transition metal (e.g., Co, Ni, Mn, Fe, Al, V, or a combination thereof). In some aspects, the LiTMO electroactive material of the positive electrode 24 may include lithium cobalt oxide (LiCoO2, LCO), spinel lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O4, LNMO), olivine manganese phosphate (LiMnPO4, LMP), lithium cobalt phosphate (LiCoPO4, LCP), or a combination thereof. The LiTMO electroactive material may be present in the positive electrode 24 in an amount greater than or equal to about 50%, optionally greater than or equal to about 80%, optionally greater than or equal to about 85%, or optionally greater than or equal to about 90% and less than or equal to about 98%, optionally less than or equal to about 95%, or optionally less than or equal to about 90% by weight.

[0067] In some aspects, the LiTMO electroactive material of the positive electrode 24 includes a nickel-rich lithium transition metal oxide (nickel-rich LiTMO) represented by formula (1):

[0068] Li1+a Ni x Me y O2,(1)

[0069] where Me is a transition metal, 0 ≤ a ≤ 1, 0.5 < x ≤ 1, 0 ≤ y < 0.5, and x + y = approximately 1. In some aspects, in the Ni-rich LiTMO of formula (1), Me is a transition metal selected from cobalt (Co), manganese (Mn), aluminum (Al), and combinations thereof. In some aspects, in the Ni-rich LiTMO of formula (1), a is greater than or equal to zero (0), optionally greater than or equal to approximately 0.001, optionally greater than or equal to approximately 0.01, or optionally greater than or equal to approximately 0.1 and less than or equal to approximately 0.4, optionally less than or equal to approximately 0.3, optionally less than or equal to approximately 0.2, or optionally less than or equal to approximately 0.1. In aspects where a is greater than zero (0), the Ni-rich LiTMO of formula (1) can be referred to as "lithium-rich". In some aspects, in the Ni-rich LiTMO of formula (1), x is greater than approximately 0.5, optionally greater than or equal to approximately 0.6, optionally greater than or equal to approximately 0.7, or optionally greater than or equal to approximately 0.8, and less than or equal to approximately one (1), optionally less than or equal to approximately 0.9, or optionally less than or equal to approximately 0.8. In some aspects, in the Ni-rich LiTMO of formula (1), y is greater than or equal to zero (0), optionally greater than or equal to approximately 0.1, optionally greater than or equal to approximately 0.15, or optionally greater than or equal to approximately 0.2 and less than approximately 0.4, optionally less than or equal to approximately 0.3, or optionally less than or equal to approximately 0.25.

[0070] The Ni-rich LiTMO of formula (1) is "nickel-rich", meaning that the molar ratio of Ni to Me in the Ni-rich LiTMO of formula (1) is greater than one (1). For example, in some aspects, the molar ratio of Ni to Me in the Ni-rich LiTMO of formula (1) is greater than or equal to approximately 1.5, optionally greater than or equal to approximately 3, or optionally greater than or equal to approximately 5 and less than or equal to approximately 50, or optionally less than or equal to approximately 20.

[0071] Examples of the Ni-rich LiTMO of formula (1) include lithium nickel cobalt manganese oxide (NCM) (Li a Ni x Co y Mn 1-x-y O2, where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4), lithium nickel cobalt aluminum oxide (NCA) (Li a Ni x Co y Al 1-x-y O2, where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, and 0 < y < 0.4), lithium nickel cobalt manganese aluminum oxide (NCMA) (Li aNi x Co y Mn z Al 1-x-y-z O2, where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, 0 < y < 0.4, and 0 < z < 0.4), lithium nickel oxide (LNO, LiNiO2), and combinations thereof.

[0072] The Ni-rich LiTMO of formula (1) can be present in the positive electrode 24 in an amount greater than or equal to about 50% by weight, optionally greater than or equal to about 80% by weight, optionally greater than or equal to about 85% by weight, or optionally greater than or equal to about 90% by weight and less than or equal to about 98% by weight, optionally less than or equal to about 95% by weight, or optionally less than or equal to about 90% by weight.

[0073] The electrochemically inert OSM of the positive electrode 24 is formulated to act as an "oxygen buffer" by reversibly storing and releasing oxygen through a reversible redox reaction with oxygen in the positive electrode 24. Without intending to be bound by theory, it is believed that the OSM can scavenge oxygen generated in the battery pack 20 and thus help prevent or inhibit the generated oxygen from interacting and / or reacting with other components of the battery pack 20 and reducing the electrochemical performance of the battery pack 20. Oxygen can be generated in the battery pack 20, for example, during high-temperature operation of the battery pack 20, which may trigger thermal decomposition of the LiTMO electroactive material of the positive electrode 24 and release oxygen therefrom. It is believed that the OSM can help prevent or inhibit the generation of undesired heat in the battery pack 20, for example, by preventing or inhibiting an exothermic reaction between the oxygen generated in the battery pack 20 and the electrolyte 28.

[0074] In addition, without intending to be bound by theory, it is believed that the OSM can help improve the capacity retention of the battery pack 20, for example, by increasing the reversibility of the phase change occurring in the LiTMO electroactive material of the positive electrode 24 during cycling of the battery pack 20. For example, the OSM can provide an easily accessible oxygen source to the LiTMO electroactive material of the positive electrode 24 (e.g., the Ni-rich LiTMO of formula (1)), which may be beneficial or necessary for the LiTMO electroactive material of the positive electrode 24 to transform back to the layered structure after transforming into the spinel or rock salt structure. By helping prevent or inhibit oxygen from participating in undesired reactions with the electrolyte 28 and / or by increasing the reversibility of the phase change occurring in the LiTMO electroactive material of the positive electrode 24 during cycling of the battery pack 20, the OSM can help improve the thermal stability and cycling stability of the battery pack 20.

[0075] The benefits of including OSM in the positive electrode 24 of the present disclosure can be achieved without substantially reducing the capacity of the positive electrode 24. In addition, even when OSM is present in the positive electrode 24 in a relatively small amount (e.g., about 5 wt%), the presence of OSM can result in an unexpectedly significant reduction (e.g., about 30%) in the heat generated in the battery 20 compared to the heat that would otherwise be generated by the positive electrode 24 if it did not include OSM. For example, when the weight ratio of OSM to LiTMO electroactive material (e.g., Ni-rich LiTMO of formula (1)) in the positive electrode 24 is about 1:19, the specific capacity of the positive electrode 24 can be reduced by about 5.5%, while the heat released from the positive electrode 24 can be unexpectedly reduced by about 29%, compared to a positive electrode having substantially the same composition but not including OSM.

[0076] The OSM may be present in the positive electrode 24 in an amount greater than or equal to about 1%, optionally greater than or equal to about 2%, or optionally greater than or equal to about 3% and less than or equal to about 10%, optionally less than or equal to about 8%, or optionally less than or equal to about 7% by weight. In some aspects, the OSM may constitute about 5% by weight of the positive electrode 24. The weight ratio of OSM to LiTMO electroactive material in the positive electrode 24 may be greater than or equal to about 1:99 (OSM:LiTMO electroactive material), optionally greater than or equal to about 2:98, or optionally greater than or equal to about 3:97 and less than or equal to about 1:9, optionally less than or equal to about 8:92, or optionally less than or equal to about 7:93. In some aspects, the weight ratio of OSM to LiTMO electroactive material in the positive electrode 24 may be about 1:19.

[0077] The electrochemically inert OSM may have an oxygen storage capacity of greater than or equal to about 400 micromoles of oxygen per gram (μmol-O / g), optionally greater than or equal to about 600 μmol-O / g, optionally greater than or equal to about 800 μmol-O / g, optionally greater than or equal to about 1000 μmol-O / g, optionally greater than or equal to about 1200 μmol-O / g, or optionally greater than or equal to about 1300 μmol-O / g.

[0078] The electrochemically inert OSM comprises a material capable of storing oxygen and subsequently releasing oxygen therefrom without interfering with the electrochemical reactions occurring within the positive electrode 24 and without participating in undesirable side reactions with other components of the battery 20. The OSM of the positive electrode 24 does not participate in the electrochemical reactions occurring within the battery 20 and is not configured to and does not store or accommodate lithium ions in its crystal structure. The OSM may have a crystalline structure, an amorphous structure, or a combination thereof. In some aspects, the OSM may store oxygen in its lattice structure.

[0079] In some aspects, the electrochemically inert OSM may include a monometallic oxide containing a single metal cation, a mixed metal oxide containing cations of two or more different metal elements, a solid solution of a monometallic oxide or a mixed metal oxide, or a combination thereof. For example, the OSM may include oxides of cerium (Ce), manganese (Mn), zirconium (Zr), gadolinium (Gd), samarium (Sm), copper (Cu), titanium (Ti), calcium (Ca), lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), aluminum (Al), praseodymium (Pr), neodymium (Nd), promethium (Pm), nickel (Ni), manganese (Mn), beryllium (Be), yttrium (Y), or a combination thereof. In some aspects, the OSM may include a CeO2-ZrO2 solid solution having a pyrochlore crystal structure. In some aspects, the OSM may include a composite of a monometallic oxide and / or a mixed metal oxide with an inorganic metal compound (i.e., a ceramic material). For example, the OSM may include a composite of a monometallic oxide and / or a mixed metal oxide and a metal nitride, a metal carbide (eg, tungsten carbide, WC), a metal boride, or a combination thereof.

[0080] Examples of monometallic oxides include CeO2, MnO2, ZrO2, Gd2O3, and combinations thereof (e.g., solid solutions of CeO2-ZrO2 and / or CeO2-Gd2O3). Examples of mixed metal oxides include oxides of yttrium and barium, cobalt, cobalt, manganese, copper, or combinations thereof (e.g., YBaCo4O 7+δ 、YMnO 3+δ and / or YBa2Cu3O 7-δ) ), having the formula RMnO 3+δ Hexagonal rare earth manganites, wherein R is a rare earth element of Ho, Er, Tm, Yb and / or Lu, and oxides having a perovskite, delafossite or pyrochlore crystal structure. The oxide having a perovskite crystal structure has the formula ABO3, wherein A is an alkaline earth metal (Be, Mg, Ca, Sr, Ba or Ra) or a rare earth element (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y or Sc) and B is a 3d, 4d or 5d transition metal element. Examples of oxides having a perovskite crystal structure include SrCoO 3-δ 、SrFeO 3-δ and combinations thereof. Oxides having a delafossite crystal structure have the formula ABO2, wherein A is Cu or Ag and B is Al, Cr, Fe, In, Nd or Y. Examples of oxides having a delafossite crystal structure include CuFeO2, CuMnO2 and combinations thereof. Oxides having a pyrochlore crystal structure (Fd3m) have the formula A2B2O6 and / or A2B2O7, wherein A and B are each a transition metal or a rare earth metal.

[0081] In some aspects, the OSM of the positive electrode 24 can be doped with lithium, which can help maintain or increase the lithium-ion conductivity of the positive electrode 24. The OSM of the positive electrode 24 can be doped with lithium or lithiated, for example, by incorporating lithium into the crystal structure of the OSM. The OSM of the positive electrode 24 can be doped with lithium or lithiated, for example, by mixing the OSM with a lithium salt (e.g., LiOH, Li2CO3, LiNO3, and / or LiPF6), lithium nitride, lithium hydride, lithium halide, or a combination thereof, and then sintering the mixture for lithiation. Examples of lithiated OSM include lithium cerium oxide, lithium cerium phosphate, lithium cerium halide, lithium cerium sulfate, lithium cerium nitrate, and combinations thereof.

[0082] An optional electrochemically inert solid lithium-conducting material can be formulated to help maintain or improve the lithium-ion conductivity of the positive electrode 24. Examples of solid lithium-conducting materials include lithium oxides having a perovskite crystal structure (e.g., lithium lanthanum titanium oxide La 2 / 3-x Li 3x TiO3, LLTO), lithium oxides having a garnet crystal structure (e.g., lithium lanthanum zirconium oxide, La3Li7Zr2O 12 , LLZO), lithium thiophosphate or lithium phosphorus sulfide (LPS), lithium phosphate (e.g., lithium aluminum titanium phosphate, Li 1+ x Al x Ti 2-x (PO4) 3x , LATP), lithium superionic conductors (LISICON) having the formula Li 2+2x Zn 1-x GeO4, LISICON-type materials (e.g., Li (3+x) Ge x V (1-x) O4, where 0 < x < 1), materials having the formula Li (4-x) Ge (1-x) P x S4 thio-LISICON materials, thio-LISICON-type materials, sodium superionic conductors (NASICON), NASICON-type materials, and combinations thereof. Examples of LPS include Li3PS4; Li7P3S 11 ; and Li4P2S6; lithium argyrodites having the formula Li6PS5X, where X is Cl, Br, or I; lithium phosphorus sulfides having the formula Li x MP x S x , where M is Ge, Si, Sn, or Al (e.g., lithium germanium phosphorus sulfide, Li 10 GeP2S 12, LGPS) and combinations thereof. When present, the optional solid lithium conductive material can be present in the positive electrode 24 in an amount greater than 0%, optionally greater than or equal to about 0.5%, or optionally greater than or equal to about 1% and less than or equal to about 4%, optionally less than or equal to about 3%, or optionally less than or equal to about 2% by weight.

[0083] The LiTMO electroactive material, OSM, and optional solid lithium conductive material may be particulate materials, and the particles of the LiTMO electroactive material, OSM, and optional solid lithium conductive material may be substantially uniformly distributed throughout the positive electrode 24. The particles of the LiTMO electroactive material, OSM, and / or optional solid lithium conductive material may have a circular geometry or an axial geometry. The term "axial geometry" refers to particles that are generally rod-shaped, fibrous, or other cylindrical shapes with a distinct long axis or slender axis. Typically, the aspect ratio (AR) of a cylindrical shape (e.g., a fiber or rod) is defined as AR=L / D, where L is the length of the longest axis and D is the diameter of the cylinder or fiber. Exemplary axial geometry particles may have a high aspect ratio, for example ranging from about 10 to about 5,000. Examples of particles having an axial geometry include fibers, wires, flakes, whiskers, filaments, tubes, rods, and the like. The term "circular geometry" is generally applicable to particles having a lower aspect ratio, for example, an aspect ratio close to 1 (e.g., less than 10). It should be noted that the particle geometry can vary from a true circular shape and can include, for example, oblong or elliptical shapes, including prolate or oblate spheroids, agglomerated particles, polygonal (e.g., hexagonal) particles, or other shapes generally having a low aspect ratio. An oblate spheroid can have a relatively high aspect ratio disk shape. Thus, generally circular geometry particles are not limited to relatively low aspect ratios and spherical shapes.

[0084] In aspects where the positive electrode 24 comprises a solid lithium conductive material, the OSM and the solid lithium conductive material may be in direct physical contact with each other in the positive electrode 24. For example, the OSM and the solid lithium conductive material may be physically combined in a powder form, wherein each particle in the powder comprises an OSM and a solid lithium conductive material.

[0085] The positive electrode 24 may be in the form of a continuous porous layer disposed on the main surface of the positive electrode current collector 32. In this case, the LiTMO electroactive material, OSM, and optional solid lithium conductive material may be particulate materials, and the particles of the LiTMO electroactive material, OSM, and optional solid lithium conductive material may be mixed with a polymer binder and / or a conductive material. The polymer binder may be formulated to provide structural integrity to the positive electrode 24 and help the positive electrode 24 adhere to the main surface of the positive electrode current collector 32. Examples of polymer binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene propylene diene rubber (EPDM), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), nitrile rubber (NBR), styrene butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), polyacrylates, alginate, polyacrylic acid, and combinations thereof. The conductive material may be formulated to provide sufficient conductivity to the positive electrode 24 to support electrons permeating therefrom. Examples of conductive materials include carbon-based materials, metals (e.g., nickel), and / or conductive polymers. Examples of conductive carbon-based materials include carbon black (CB) (e.g., acetylene black), graphite, graphene (e.g., graphene nanosheets, GNPs), graphene oxide, carbon nanotubes (CNTs), and / or carbon fibers (e.g., carbon nanofibers). Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, and / or polypyrrole. The polymer binder and the conductive material may each be present in the positive electrode 24 in an amount greater than or equal to about 0.5%, or optionally greater than or equal to about 1%, or optionally greater than or equal to about 5% and less than or equal to about 30%, optionally less than or equal to about 20%, or optionally less than or equal to about 10% by weight.

[0086] The negative electrode 22 is configured to store and release lithium ions during the charge and discharge process of the battery 20. The negative electrode 22 can be in the form of a continuous material layer disposed on the main surface of the negative electrode current collector 30. The negative electrode 22 is configured to store and release lithium ions to facilitate the charge and discharge of the battery 20, respectively. To achieve this, the negative electrode 22 includes one or more electrochemically active (electroactive) materials that can facilitate the storage and release of lithium ions by undergoing a reversible redox reaction with lithium during the charge and discharge process of the battery 20. Examples of electroactive materials for the negative electrode 22 include lithium, lithium-based materials, lithium alloys (e.g., alloys of lithium with silicon, aluminum, indium, tin, or a combination thereof), carbon-based materials (e.g., graphite, activated carbon, carbon black, hard carbon, soft carbon, and / or graphene), silicon, silicon-based materials (e.g., silicon oxide, alloys of silicon with tin, iron, aluminum, cobalt, or a combination thereof, and / or a composite of silicon and / or silicon oxide and carbon), tin oxide, aluminum, indium, zinc, germanium, silicon oxide, lithium silicon oxide, lithium silicide, titanium oxide, lithium titanate, and a combination thereof.

[0087] In some aspects, the negative electrode 22 can be in the form of a non-porous metal film or foil, such as a lithium metal film or lithium metal foil. In other aspects, the negative electrode 22 can be porous and the electroactive material of the negative electrode 22 can be a particulate material. In aspects where the electroactive material of the negative electrode 22 is a particulate material, the particles of the electroactive material of the negative electrode 22 can be mixed with particles of a polymer binder and / or a conductive material. The same polymer binder and / or conductive material disclosed above with respect to the positive electrode 24 can be used in the negative electrode 22.

[0088] The separator 26 physically separates and electrically isolates the negative electrode 22 and the positive electrode 24 from each other while allowing lithium ions to pass therethrough. The separator 26 has an open microporous structure and may include organic and / or inorganic materials. For example, the separator 26 may include a polymer or a combination of polymers. For example, the separator 26 may include one or more polyolefins, such as polyethylene (PE), polypropylene (PP), polyamide (PA), poly(tetrafluoroethylene) (PTFE), polyvinylidene fluoride (PVdF) and / or poly(vinyl chloride) (PVC). In one form, the separator 26 may include a polymer laminate, such as a laminate of PE and PP. In some aspects, the separator 26 may include a ceramic coating (not shown) disposed on one or both sides thereof. In this case, the ceramic coating may include particles of aluminum oxide (Al2O3) and / or silicon dioxide (SiO2).

[0089] The electrolyte 28 is ionically conductive and provides a medium for lithium ions to be conducted between the negative electrode 22 and the positive electrode 24 through the battery 20. The electrolyte 28 can be in the form of a solid, a liquid, or a gel. In some aspects, the electrolyte 28 can include a non-aqueous liquid electrolyte solution that includes a lithium salt dissolved in a non-aqueous aprotic organic solvent or a mixture of non-aqueous aprotic organic solvents. Non-limiting examples of lithium salts include lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF4), lithium tetraphenylborate (LiB(C6H5)4), lithium bis(oxalato)borate (LiB(C2O4)2) (LiBOB), lithium difluorooxalatoborate (LiBF2(C2O4)), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethane)sulfonyl imide (LiN(CF3SO2)2), lithium bis(fluorosulfonyl)imide (LiN(FSO2)2) (LiSFI), (triethylene glycol dimethyl ether) bis(trifluoromethane)sulfonyl imide (LiN(CF3SO2)2), lithium bis(fluorosulfonyl)imide (LiN(FSO2)2) (LiSFI), The non-aqueous aprotic organic solvents include lithium bis(trifluoromethanesulfonyl)imide (Li(G3) (TFSI), lithium bis(trifluoromethanesulfonyl)azine (LiTFSA), and combinations thereof. Non-limiting examples of non-aqueous aprotic organic solvents include cyclic carbonates (e.g., ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC)), linear carbonates (e.g., dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC)), aliphatic carboxylates (e.g., methyl formate, methyl acetate, methyl propionate), γ-lactones (e.g., γ-butyrolactone, γ-valerolactone), chain structure ethers (e.g., 1,2-dimethoxyethane, 1-2-diethoxyethane, ethoxymethoxyethane), cyclic ethers (e.g., tetrahydrofuran, 2-methyltetrahydrofuran), 1,3-dioxolane).

[0090] The positive electrode current collector 30 and the negative electrode current collector 32 are conductive and provide an electrical connection between the external circuit 36 ​​and its corresponding positive electrode 22 and negative electrode 24. In some aspects, the positive electrode current collector 30 and the negative electrode current collector 32 can be in the form of a non-porous metal foil, a perforated metal foil, a porous metal mesh, or a combination thereof. The negative electrode current collector 30 can be made of copper, nickel, or alloys thereof, stainless steel, or other suitable conductive materials. The positive electrode current collector 32 can be made of aluminum (Al) or another suitable conductive material.

[0091] Although the present disclosure is explicitly directed to positive electrodes formulated for batteries that cycle lithium ions, a person of ordinary skill will readily appreciate that the OSM of the present disclosure can be used for positive electrodes of batteries that cycle different types of ions, such as alkali metal ions or alkaline earth metal ions. In this case, instead of including a LiTMO electroactive material, the positive electrode would include sodium transition metal oxide (NaMeO2), magnesium transition metal oxide (MgMeO2), calcium transition metal oxide (CaMeO2), or zinc transition metal oxide (ZnMeO2) as the electroactive material, where Me is a transition metal.

[0092] The foregoing description is essentially only exemplary and is absolutely not intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be limited thereto, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that one or more steps in the method may be implemented in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more features described in any embodiment of the present disclosure may be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the embodiments are not mutually exclusive, and the mutual replacement of one or more embodiments is still within the scope of the present disclosure.

[0093] The terms used herein are only for the purpose of describing specific exemplary embodiments, and are not intended to be limiting. Unless the context clearly indicates otherwise, as used herein, the singular forms "a", "an" and "the" may be intended to also include plural forms. The terms "comprise", "include", "cover" and "have" are compatible, and therefore specify the presence of the features, elements, compositions, steps, integers, operations and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. Although the open term "comprising" should be understood as a non-limiting term for describing and claiming the various embodiments described herein, in some aspects, the term may be understood as alternatively being a more restrictive and limited term, such as "consisting of..." or "consisting essentially of..." Thus, for any given embodiment of a narration composition, material, assembly, element, feature, integer, operation and / or method step, the present disclosure also specifically includes an embodiment consisting of or essentially consisting of such narrated compositions, materials, assemblies, elements, features, integers, operations and / or method steps. In the case of “consisting of,” alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operations, and / or method steps, while in the case of “consisting essentially of,” any additional compositions, materials, components, elements, features, integers, operations, and / or method steps that materially affect the basic and novel characteristics are excluded from such embodiments, but any compositions, materials, components, elements, features, integers, operations, and / or method steps that do not materially affect the basic and novel characteristics may be included in the embodiments.

[0094] Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless expressly identified as an order of performance. It is also to be understood that additional or alternative steps may be employed unless otherwise stated.

[0095] Although the terms first, second, third, etc. can be used to describe various steps, elements, components, regions, layers and / or sections in this article, unless otherwise specified, these steps, elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish a step, element, component, region, layer or section from another step, element, component, region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in this article. Therefore, the first step, element, component, region, layer or section discussed below can be referred to as the second step, element, component, region, layer or section without departing from the teaching of exemplary embodiments.

[0096] Throughout this disclosure, numerical values ​​represent approximate measurements or range limits to cover slight deviations from given values ​​and embodiments having approximately the values ​​mentioned and embodiments having exactly the values ​​mentioned. Except in the working examples provided at the end of the detailed description, all numerical values ​​of (e.g., amounts or conditions) parameters in this specification (including the appended claims) should be understood to be modified by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. "About" means that the numerical value allows a certain slight imprecision (close to the exact value of the value to a certain extent; approximately or reasonably approximate the value; almost). If the imprecision provided by "about" is not otherwise understood in this ordinary sense in the art, then "about" as used herein refers to at least the deviation that can be caused by the common methods of measuring and using such parameters. For example, "about" may include less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some aspects optionally less than or equal to 0.1% deviation. Furthermore, the disclosure of a range includes disclosure of all values ​​within the entire range and further subdivided ranges, including disclosure of endpoints and subranges given for that range.

[0097] As used herein, the terms "composition" and "material" are used interchangeably and refer generally to a substance that contains at least a preferred chemical constituent, element, or compound, but which may also contain additional elements, compounds, or substances, including trace impurities, unless otherwise specified. A composition or material "based on X" refers generally to a composition or material in which "X" is the single largest component of the composition or material by weight percentage (%). This can include compositions or materials having greater than 50 wt % X, as well as compositions or materials having less than 50 wt % X, as long as X is the single largest component of the composition or material based on its overall weight. When a composition or material is referred to as being "substantially free" of a substance, the composition or material may contain less than 5%, optionally less than 3%, optionally less than 1%, or optionally less than 0.1% by weight of the substance.

[0098] As used herein, the term "metal" may refer to a pure elemental metal or an alloy of an elemental metal with one or more other metals or nonmetallic elements, referred to as "alloying" elements. Alloying elements may be selected to impart certain desirable properties to the alloy that are not exhibited by the base metal element.

Claims

1. A positive electrode for a battery pack for cycling lithium ions, the positive electrode comprising: An electroactive material comprising a lithium transition metal oxide (LiTMO) formulated for reversible intercalation of lithium ions, the LiTMO comprising at least one of: (i) A nickel-rich lithium transition metal oxide (Ni-rich LiTMO) represented by the formula Li 1+a Ni x Me y O2, where Me is a transition metal, 0 ≤ a ≤ 1, 0.5 < x ≤ 1, 0 ≤ y < 0.5, and x + y = approximately 1; or (ii) Layered lithium-rich transition metal oxide represented by the formula Li 1+x Me 1-x O2, where 0 < x ≤ 0.5 and Me is a transition metal; and an electrochemically inert oxygen storage material (OSM) formulated to store oxygen released from the LiTMO; Polymer Binders. 2 . The positive electrode according to claim 1 , wherein Me is a transition metal selected from the group consisting of cobalt (Co), manganese (Mn), aluminum (Al), and combinations thereof. 3 . The positive electrode according to claim 1 , wherein the LiTMO comprises the Ni-rich LiTMO.

4. The positive electrode according to claim 3, wherein the LiTMO comprises Ni-rich LiTMO, and wherein the Ni-rich LiTMO comprises Li a Ni x Co y Mn 1-x-y O2 (NCM), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1 and 0 < y < 0.4; Li a Ni x Co y Al 1-x-y O2 (NCA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1 and 0 < y < 0.4; (Li a Ni x Co y Mn z Al 1-x-y-z O2 (NCMA), where 0 ≤ a ≤ 1, 0.6 ≤ x < 1, 0 < y < 0.4 and 0 < z < 0.4), LiNiO2 (LNO) or a combination thereof. 5 . The positive electrode according to claim 1 , wherein the LiTMO comprises the layered lithium-rich transition metal oxide.

6. The positive electrode of claim 1, wherein the LiTMO constitutes greater than or equal to about 80% and less than or equal to about 95% by weight of the positive electrode, and wherein the OSM constitutes greater than or equal to about 1% and less than or equal to about 10% by weight of the positive electrode.

7. The positive electrode of claim 1, wherein the OSM comprises a monometallic oxide, a mixed metal oxide, a solid solution of a monometallic oxide or a mixed metal oxide, or a combination thereof, and wherein the OSM comprises an oxide of cerium (Ce), manganese (Mn), zirconium (Zr), gadolinium (Gd), samarium (Sm), copper (Cu), titanium (Ti), calcium (Ca), lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), aluminum (Al), praseodymium (Pr), neodymium (Nd), promethium (Pm), nickel (Ni), manganese (Mn), beryllium (Be), yttrium (Y), or a combination thereof.

8. The positive electrode of claim 1, wherein the OSM comprises a metal nitride, a metal carbide, a metal boride, or a combination thereof.

9. The positive electrode of claim 1, wherein the OSM has a lattice structure and is configured to store oxygen in its lattice structure, and wherein the OSM has an oxygen storage capacity greater than or equal to about 400 micromoles oxygen / gram.

10. The positive electrode of claim 1, further comprising an electrochemically inert solid lithium conductive material comprising lithium oxide, lithium phosphosulfide, lithium phosphate, or a combination thereof, wherein the electrochemically inert solid lithium conductive material is in physical contact with the OSM.

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