PATENT DOCUMENT

Publication Number: US-10581070-B2
Application Number: US-201715551353-A
Country: US
Kind Code: B2

Title: Coated nickel-based cathode materials and methods of preparation

Abstract:
Cathode active materials have composite particles each with a base particle having the following formula: LiαNixMyCozO2, wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al, and coating particles coating each base particle, the coating particles having the following formula: LiaNibMncCodO2, wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1.

Claims:
What is claimed is: 
     
       1. A cathode active material, comprising:
 a base particle formed of a single particle having the following formula:
   Li α Ni x M y Co z O 2 , 
 
 
       wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.4, 0≤z≤0.4 in mol percent; x+y+z=1; and M is one of Mn and Al; and
 coating particles forming a coating on the base particle, the coating particles having the following formula:
   Li a Ni b Mn c Co d O 2 , 
 
 
       wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 in mol percent and b+c+d=1, wherein the base particle has a particle diameter ranging from 8 μm to 25 μm and each coating particle has a particle diameter ranging from 0.1 μm to 5 μm,
 wherein the base particle has one of the following compositions: Li 1.02 Ni 0.8 Mn 0.1 Co 0.1 O 2 , Li 1.02 Ni 0.82 Mn 0.11 Co 0.07 O 2 , Li 1.02 Ni 0.94 Mn 0.03 Co 0.03 O 2 , Li a Ni 0.8 Co 0.15 Al 0.05 O 2  and Li 1.02 Ni 0.89 Co 0.1 Al 0.01 O 2  and the coating particles have one of the following compositions: Li a Ni 1/3 Mn 1/3 Co 1/3 O 2 , Li a Mn 0.07 Ni 0.07 Co 0.86 O 2  and Li a Co 0.96 Mn 0.04 O 2 . 
 
     
     
       2. The cathode active material of  claim 1 , wherein an amount of the coating particles is &gt;0.0 wt. % and ≤30 wt. % of the cathode active material. 
     
     
       3. The cathode active material of  claim 1 , wherein one or both the base particle and the coating particles are doped with one or more of B, Mg, Al, Ca, Ti, V, Si, F, Cr, Cu, Zn, Zr, Mo and Ru. 
     
     
       4. The cathode active material of  claim 1 , having an outer coating of a metal oxide, a metal fluoride or a metal phosphate. 
     
     
       5. The cathode active material of  claim 1 , having a pellet density of ≥3.4 g/cc. 
     
     
       6. A battery cell, comprising:
 an anode, comprising:
 an anode current collector; and 
 an anode active material disposed over the anode current collector; and 
 
 a cathode, comprising:
 a cathode current collector; and 
 a cathode active material disposed over the cathode current collector, the cathode active material as claimed in  claim 1 . 
 
 
     
     
       7. The battery cell of  claim 6 , wherein the cathode active material has an outer coating of a metal oxide, a metal fluoride or a metal phosphate. 
     
     
       8. A method of preparing a cathode active material, comprising:
 lithiating a coating precursor to produce coating particles having the following formula: 
 Li α Ni b Mn c Co d O 2 , wherein 0.95≤α≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 in mol percent and b+c+d=1;
 lithiating a base precursor to produce base particles having the following formula: 
 Li a Ni x M y Co z O 2 , wherein 0.95≤a≤1.5, 0.6≤x≤1.0, 0≤y≤0.4, 0≤z≤0.4 in mol percent; x+y+z=1; and M is one of Mn and Al; and 
 producing the cathode active material by one of:
 coating individual base particles with the coating particles; 
 coating individual base precursor particles with the coating precursor prior to lithiating each of the individual base precursor particles and the coating precursor; and 
 coating the individual base particles with the coating precursor prior to lithiating the coating precursor, wherein each individual base particle has a particle diameter ranging from 8 μm to 25 μm and the coating particles each have a particle diameter ranging from 0.1 μm to 5 μm; 
 
 wherein the base particle has one of the following compositions: Li 1.02 Ni 0.8 Mn 0.1 Co 0.1 O 2 , Li 1.02 Ni 0.82 Mn 0.11 Co 0.07 O 2 , Li 1.02 Ni 0.94 Mn 0.03 Co 0.03 O 2 , Li a Ni 0.8 Co 0.15 Al 0.05 O 2  and Li 1.02 Ni 0.89 Co 0.1 Al 0.01 O 2  and the coating particles have one of the following compositions: Li a Ni 1/3 Mn 1/3 Co 1/3 O 2 , Li a Mn 0.07 Ni 0.07 Co 0.86 O 2  and Li a Co 0.96 Mn 0.04 O 2 . 
 
 
     
     
       9. The method of  claim 8 , wherein an amount of the coating particles is &gt;0.0 wt. % and ≤30 wt. % of the cathode active material. 
     
     
       10. The method of  claim 8 , further comprising:
 doping one or both of the individual base particles and the coating particles with one or more of B, Mg, Al, Ca, Ti, V, Si, F, Cr, Cu, Zn, Zr, Mo and Ru. 
 
     
     
       11. The method of  claim 10 , further comprising:
 coating the active cathode material with a metal oxide, a metal fluoride or a metal phosphate. 
 
     
     
       12. The method of  claim 8 , wherein the cathode active material has a pellet density of ≥3.4 g/cc.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/369,884, filed on Aug. 2, 2016, and entitled “Coated Nickel-Based Cathode Materials and Methods of Preparation,” which is incorporated herein in its entirety by reference. 
    
    
     TECHNICAL FIELD 
     This application generally relates to rechargeable lithium batteries. 
     BACKGROUND 
     Rechargeable lithium batteries are widely used as an energy source for both small and large electronic devices. Lithium batteries may use cathode materials containing nickel. However, nickel-based cathode materials can contribute to low volumetric energy density, high-percent capacity irreversibility in the first cycle, capacity degradation as a function of cycle number, and low rate capabilities. 
     SUMMARY 
     The disclosed embodiments provide cathode active materials that comprise a base particle having the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. The cathode active materials further comprise coating particles coated on the base particle, the coating particles having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. 
     In some embodiments, the base particle has a particle diameter ranging from 8 μm to 25 μm and the coating particles have a particle diameter ranging from 0.1 μm to 5 μm. 
     In some embodiments, the coating particles are &gt;0.0 wt. % and ≤30 wt. % of the cathode active material. 
     In some embodiments, one or both the base particle and the coating particles are doped with one or more of B, Mg, Al, Ca, Ti, V, Si, F, Cr, Cu, Zn, Zr, Mo and Ru. 
     In some embodiments, the cathode active material is coated with a metal oxide, a metal fluoride or a metal phosphate. 
     In some embodiments, the cathode active material has a pellet density of ≥3.4 g/cc. 
     In some embodiments, in the formula of the base particle, 0.8≤x≤1.0. 
     In some embodiments, in the formula of the coating particles, b=0. 
     In some embodiments, the base particle has one of the following compositions: Li 1.02 Ni 0.8 Mn 0.1 Co 0.1 O 2 , Li 1.02 Ni 0.82 Mn 0.11 Co 0.07 O 2  and Li 1.02 Ni 0.94 Mn 0.03 Co 0.03 O 2  and the coating particles have one of the following compositions: Li a Ni 1/3 Mn 1/3 Co 1/3 O 2 , Li a Mn 0.07 Ni 0.07 Co 0.86 O 2 , Li a Co 0.96 Mn 0.04 O 2 , and Li 2 MnO 3 . 
     In some embodiments, the base particle has the one of the following composition: Li a Ni 0.8 Co 0.15 Al 0.05 O 2  and Li 1.02 Ni 0.89 Co 0.1 Al 0.01 O 2 , and the coating particles have one of the following compositions: Li a Ni 1/3 Mn 1/3 Co 1/3 O 2 , Li a Mn 0.07 Ni 0.07 Co 0.86 O 2 , Li a Co 0.96 Mn 0.04 O 2 , and Li 2 MnO 3 . 
     An aspect of the disclosed embodiments includes a battery cell having an anode comprising an anode current collector and an anode active material disposed over the anode current collector. The battery cell further comprises a cathode comprising a cathode current collector and a cathode active material disposed over the cathode current collector. The cathode active material comprises a base particle having the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al; and coating particles coating the base particle, the coating particles having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. 
     Other aspects of the disclosed embodiments include methods of preparing the cathode active material. One method disclosed herein comprises forming a cathode precursor by coating a base precursor with a coating precursor, the base precursor being one of an oxide, hydroxide, carbonate or oxalate of Ni x M y Co z , wherein 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. The coating precursor is one of an oxide, hydroxide, carbonate or oxalate of Ni b Mn c Co d , wherein 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. The cathode precursor is lithiated to produce cathode active materials with coating particles having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1, and base particles having the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. 
     Another method of preparing the cathode active material comprises lithiating a base precursor, the base precursor being one of an oxide, hydroxide, carbonate or oxalate of Ni x M y Co z , wherein 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5, x+y+z=1, and M is one of Mn and Al, forming a base particle. The base particle has the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. The base particle is coated with a coating precursor, the coating precursor being one of an oxide, hydroxide, carbonate or oxalate of Ni b Mn c Co d , wherein 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. The coating precursor is lithiated, producing coating particles having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0; b+c+d=1. 
     Another method of preparing the cathode active material comprises lithiating a coating precursor to produce coating particles having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. A base precursor is lithiated to produce base particles having the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. The cathode active material is produced by coating the base particles with the coating particles. 
     In some embodiments, the method further comprises coating the cathode active material with a metal oxide, a metal fluoride or a metal phosphate. 
     In some embodiments, the method further comprises doping one or both the base particles and the coating particles with one or more of B, Mg, Al, Ca, Ti, V, Si, F, Cr, Cu, Zn, Zr, Mo and Ru. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of an exemplary cathode active material. 
         FIG. 2  is a schematic of the crystal structure of LiMO 2 , where M=Ni, Co or Mn. 
         FIG. 3  is a schematic of the crystal structure of Al 2 O 3 . 
         FIG. 4  is an illustration showing a cross-sectional view of an exemplary battery cell. 
         FIG. 5  is a flow diagram of an embodiment of methods of preparing the cathode active material. 
         FIG. 6  is a schematic of the embodiment of methods of preparing the cathode active material of  FIG. 5 . 
         FIG. 7  is a flow diagram of another embodiment of methods of preparing the cathode active material. 
         FIG. 8  is a schematic of the embodiment of methods of preparing the cathode active material of  FIG. 7 . 
         FIG. 9  is a flow diagram of another embodiment of methods of preparing the cathode active material. 
         FIG. 10  is a schematic of the embodiment of methods of preparing the cathode active material of  FIG. 9 . 
         FIG. 11  is a scanning electron microscope (SEM) image of a cross section of a cathode active material particle of Example 1. 
         FIGS. 12A and 12B  are graphs of the thermal runaway of each of the cathode active material and the base particle material, respectively, of Example 1. 
         FIG. 13  is a graph showing energy retention versus cycle number for the cathode active material of Example 1 and the base particle materials of Example 1. 
         FIG. 14  is a graph showing the discharge specific capacity versus cycle number for the cathode active material and the base particle materials of Example 1. 
         FIG. 15  is a graph showing the direct current resistance (DCR) growth versus cycle number for the cathode active material and base particle materials of Example 1. 
         FIG. 16  is a graph showing the average discharge voltage versus cycle number for the cathode active material and base particle materials of Example 1. 
         FIG. 17  is a charge/discharge profile for the cathode active material of Example 1. 
         FIG. 18  compares the change in discharge specific capacity as a function of cycle number for two cathode active materials, one having 2 wt. % coating and the other having 4 wt. % coating. 
         FIG. 19  compares the change in energy retention as a function of cycle number for the two cathode active materials of  FIG. 18 . 
         FIG. 20  is a graph of the thermal runaway of each of the cathode active material and the base particle material of Example 2. 
         FIG. 21  is a graph of the thermal runaway of each of the cathode active material and the base particle material of Example 3. 
         FIG. 22  is a graph showing energy retention versus cycle number for the cathode active material of Example 3 and the base particle materials of Example 3. 
         FIG. 23  is a graph showing the discharge specific capacity versus cycle number for the cathode active material and the base particle materials of Example 3. 
         FIG. 24  is a graph showing the direct current resistance (DCR) growth versus cycle number for the cathode active material and base particle materials of Example 3. 
         FIG. 25  is a graph showing the average discharge voltage versus cycle number for the cathode active material and base particle materials of Example 3. 
         FIG. 26  is a charge/discharge profile of the cathode active material and the base particle material of Example 4. 
         FIG. 27  is a graph of the cathode specific capacity versus cycle number for the cathode active material and base particle material of Example 4. 
         FIG. 28  is an SEM image of a cross section of a cathode active material particle of Example 5. 
     
    
    
     DETAILED DESCRIPTION 
     Nickel-based oxides are a promising class of cathode materials for lithium-ion batteries. Nickel-rich oxides have high discharge capacities (200-220 mAh/g) and thus high gravimetric energy density, greater than the discharge capacities of conventional lithium-ion cathode materials, such as LiCoO 2  (140 mAh/g), LiNi 1/3 Co 1/3 Mn 1/3 O 2  (160 mAh/g), and LiMn 2 O 4  (120 mAh/g). Nickel as a raw material is also lower in cost than cobalt. However, nickel-rich cathode materials can experience significant capacity fade upon cycling, detrimental side reactions with electrolytes, and poor thermal stability. Nickel-rich materials can also suffer from oxygen evolution from its oxide lattice in the temperature range of 150° C.-300° C. when delithiated. The exothermic decomposition temperature gradually decreases as the nickel content increases. 
     For example, a cathode using the nickel-based material LiNi 1/3 Co 1/3 Mn 1/3 O 2  exhibits high capacity retention and thermal stability among LiNi 1-2x Co x Mn x O 2  samples, where x&lt;⅓. By contrast, the cathode using LiNi 1/3 Co 1/3 Mn 1/3 O 2  has a limited discharge capacity due to the lower amount of nickel. A cathode using nickel-rich material LiNi 1-2x Co x Mn x O 2 , where x=0.2, experiences severe capacity fading. The mechanism for the capacity fade can be due to the surface structural degradation as the nickel-rich material transforms to a rock salt structure. 
     Coatings have been introduced, attempting to improve the cycle retention, rate capability, and thermal stability of nickel-rich cathode materials. The coating materials introduced include carbon, metal oxides, metal carbonates, metal aluminates, metal phosphates, metal fluorides, metal oxyfluorides, and metal hydroxides. Surface coating nickel-rich material with these coating materials can protect the cathode surface from undesired chemical reactions with the organic electrolyte and suppress solid-electrolyte interphase (SEI) layer formation, scavenge trace amounts of hydrofluoric acid present in the electrolyte, and provide structural support to impede the transition to the rock salt phase. 
     However, these coating materials, including carbon, metal oxides, metal carbonates, metal aluminates, metal phosphates, metal fluorides, metal oxyfluorides, and metal hydroxides, are not able to participate in the electrochemical reaction, resulting in a decrease in initial capacity of lithium-ion batteries. These coating materials are also insulating with respect to lithium ions, slowing down, and even blocking, the de-intercalation of lithium ions. 
     The cathode active materials having a low nickel-based lithium-containing coating on a nickel-rich base as disclosed herein optimize the composition and microstructure of nickel-rich LiNi 1-2x Co x Mn x O 2 , particularly on the surface, to attain a cathode active material with high capacity and thermal stability. The disclosed low nickel-based lithium-containing coating on a nickel-rich base does not block the de-intercalation and re-intercalation of lithium. The low nickel-based lithium-containing coating participates in the charging/discharging electrochemical reaction, and is thus able to deliver capacity. The low nickel-based lithium-containing coating provides cycle stability (i.e., continual lithium-ion extraction and insertion), and results in better thermal stability of the resulting cathode active material. The low nickel-based lithium-containing coating particles have the same crystal structure as the nickel-rich lithium-containing base particle, but with different transition metals or different amounts of the same transition metals. This coherent crystal structure of the base and the coating provides increased mobility of lithium ions across the interface, resulting in better diffusion pathways. The improved contact between the base and coating particles due to the coherent structure reduces degradation of the material as a function of cycle number. As with conventional coatings, the low nickel-based coating also protects the surface of the nickel-rich base particle from undesired chemical reactions with the organic electrolyte and suppresses solid-electrolyte interphase (SEI) layer formation, scavenges trace amounts of hydrofluoric acid present in the electrolyte, and provides structural support to impede the transition to the rock salt phase 
       FIG. 1  is a schematic of a cathode active material  100  that comprises a lithiated nickel-rich base particle  102  and lithiated low nickel-based coating particles  104  coating the base particle  102 .  FIG. 2  is a schematic of the crystal structure representing each of the base particle  102  and the coating particles  104 .  FIG. 3  is a schematic of the crystal structure of a conventional aluminum oxide coating. The crystal structure of the aluminum oxide coating is significantly different compared to the crystal structure of each of the base particle  102  and the coating particles  104 . 
     The lithiated nickel-rich base particle  102  has the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5, in mol percent; x+y+z=1; and M is one of Mn and Al. In some embodiments, 0.8≤x≤1.0, and in other embodiments, 0.9≤x≤1.0. Non-limiting examples of base particle compositions include Li 1.02 Ni 0.8 Mn 0.1 Co 0.1 O 2 , Li 1.02 Ni 0.82 Mn 0.11 Co 0.07 O 2 , Li 1.02 Ni 0.94 Mn 0.03 Co 0.03 O 2 , Li a Ni 0.8 Co 0.15 Al 0.05 O 2  and Li 1.02 Ni 0.89 Co 0.01 Al 0.01 O 2 . 
     The cathode active material further comprises lithiated low nickel-based coating particles  104  coating the base particle  102 . The coating particles  104  have the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤α≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. As used herein, “low nickel-based” coating particles  104  include coating particle compositions with no nickel. Non-limiting examples of coating particle compositions include Li a Ni 1/3 Mn 1/3 Co 1/3 O 2 , Li a Mn 0.07 Ni 0.07 Co 0.86 O 2 , Li a Co 0.96 Mn 0.04 O 2 , and Li 2 MnO 3 . 
     A non-limiting example of a cathode active material  100  includes base particles  102  of Li 1.02 Ni 0.8 Mn 0.1 Co 0.1 O 2  coated with coating particles  104  of Li a Ni 1/3 Mn 1/3 Co 1/3 O 2 . Another non-limiting example of a cathode active material  100  includes base particles  102  of LiNi 0.8 Co 0.15 Al 0.05 O 2  coated with coating particles  104  of LiNi 0.07 Mn 0.07 Co 0.86 O 2 . Any combinations of base particles  102  having the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al and coating particles  104  have the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1 are contemplated. 
     In some embodiments, the base particles  102  have a particle diameter D b  ranging from 8 μm to 25 μm and the coating particles  104  have a particle diameter D c  ranging from 0.1 μm to 5 μm. The coating particles  104  can form a uniform or non-uniform coating on part of or on an entire surface of the base particle  102 . In some embodiments, the coating particles  104  are greater than 0.0 wt. % and less than or equal to 30 wt. % of the cathode active material  100 . In some embodiments, the coating particles  104  are greater than 0.0 wt. % and less than or equal to 10.0 wt. % of the cathode active material  100 . In some embodiments, the coating particles  104  are greater than 0.0 wt. % and less than or equal to 6.0 wt. % of the cathode active material  100 . 
     The cathode active material  100  disclosed herein has a pellet density of ≥3.4 g/cc, which is typically higher than cathode materials made of nickel-rich material of the base particles alone. 
     In some embodiments, one or both the base particles  102  and the coating particles  104  are doped with a dopant to further enhance electrochemical performance, such as cycle life and thermal stability. The dopant can be one or more of B, Mg, Al, Ca, Ti, V, Si, F, Cr, Cu, Zn, Zr, Mo and Ru. In some embodiments, only the base particles  102  are doped. In some embodiments, only the coating particles  104  are doped. In some embodiments, both the base particles  102  and the coating particles  104  are doped. In such embodiments, the base particles  102  and the coating particles  104  can be doped with different elements or the same elements. 
     In some embodiments disclosed herein, the cathode active material  100  is coated with a metal oxide, a metal fluoride or a metal phosphate to further improve thermal stability and reduce gassing and swelling. The metal oxide, metal fluoride or metal phosphate can be zinc-based, boron-based, zirconium-based, aluminum-based, such as Al 2 O 3 , AlF 3 , AlPO 4 , and ZrO 2 , as non-limiting examples. The thickness of the metal oxide, metal fluoride or metal phosphate coating may vary, while maintaining uniform protection of the surface of the material. 
     An aspect of the disclosed embodiments is a battery cell  200 , the layers of which are shown in cross-section in  FIG. 4 . The battery cell  200  can be a bi-cell structure, jelly roll structure, pouch structure, or any other battery cell structure known to those skilled in the art. The battery cell  200  has an anode  202  with an anode current collector  204  and an anode active material  206  disposed over the anode current collector  204 . The battery cell  200  also has a cathode  208  with a cathode current collector  210  and a cathode active material  212  disposed over the cathode current collector  210 . The cathode active material  212  and the anode active material  206  are separated by a separator  214 . The cathode active material  212  is one of the embodiments of the cathode active material  100  disclosed herein. The layers may be wound or stacked to create the battery cell  200 . As non-limiting examples, the cathode current collector  210  may be aluminum foil, the anode current collector  204  may be copper foil, and the separator  214  may include a conducting polymer electrolyte. The anode active material  206  can be carbon. A battery pack is a plurality of battery cells  200  that can generally be used in any type of electronic device. 
     Other aspects of the disclosed embodiments include methods of preparing the cathode active material  100 .  FIG. 5  is a flow diagram of one method disclosed herein, which is schematically represented in  FIG. 6 . In step  300 , a cathode precursor  100   p  is formed by coating a base precursor  102   p  with a coating precursor  104   p . The base precursor  100   p  is one of an oxide, hydroxide, carbonate or oxalate of Ni x M y Co z , wherein 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. Non-limiting examples of the base precursor  102   p  include Ni 0.8 Mn 0.1 Co 0.1 O 2 , Ni 0.6 Mn 0.2 Co 0.2 O 2 , Ni 0.8 Co 0.15 Al 0.05 O 2 , Ni 0.8 Co 0.15 Al 0.05 (OH) 2 , Ni 0.8 Mn 0.1 Co 0.1 (OH) 2 , and Ni 0.6 Mn 0.2 Co 0.2 (OH) 2 . The coating step can be achieved with a high-speed coater or calcination, as non-limiting examples. 
     The coating precursor is one of an oxide, hydroxide, carbonate or oxalate of Ni b Mn c Co d , wherein 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. Non-limiting examples of the coating precursor  104   p  include Ni 1/3 Mn 1/3 Co 1/3 O 2 , Mn 0.07 Ni 0.07 Co 0.86 O 2 , Ni 1/3 Mn 1/3 Co 1/3 (OH) 2 , and Mn 0.07 Ni 0.07 Co 0.86 (OH) 2 . 
     The cathode precursor  100   p  is lithiated in step  302  to produce the cathode active material  100  with coating particles  104  having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1, and the base particles  102  having the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. 
     In some embodiments, the method further comprises coating the cathode active material  100  with the metal oxide, the metal fluoride or the metal phosphate, as shown in optional step  304  in  FIG. 5 . 
     In some embodiments, the method further comprises doping one or both the base particles  102  and the coating particles  104  with the dopants discussed herein. In some embodiments, only the base particles  102  are doped. In some embodiments, only the coating particles  104  are doped. In some embodiments, both the base particles  102  and the coating particles  104  are doped. The doping can occur to the base precursor  102   p  and/or the coating precursor  104   p  prior to lithiation. The doping can alternatively occur during lithiation of the base precursor  102   p  and/or the coating precursor  104   p . 
       FIG. 7  is a flow diagram of another method disclosed herein, which is schematically represented in  FIG. 8 . The same reference numbers will be used for the same particles for clarity. In step  400 , the base precursor  102   p  is lithiated, the base precursor  102   p  being one of an oxide, hydroxide, carbonate or oxalate of Ni x M y Co z , wherein 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5, x+y+z=1, and M is one of Mn and Al, forming the base particle  102 . The base particle  102  is coated in step  402  with the coating precursor  104   p , the coating precursor  104   p  being one of an oxide, hydroxide, carbonate or oxalate of Ni b Mn c Co d , wherein 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. The coating precursor  104   p  is lithiated in step  404 , producing coating particles  104  having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0; b+c+d=1. 
     In some embodiments, the method further comprises coating the cathode active material  100  with the metal oxide, the metal fluoride or the metal phosphate, as shown in optional step  406  in  FIG. 7 . 
     In some embodiments, the method further comprises doping one or both the base particles  102  and the coating particles  104  with the dopants discussed herein. In some embodiments, only the base particles  102  are doped. In some embodiments, only the coating particles  104  are doped. In some embodiments, both the base particles  102  and the coating particles  104  are doped. 
       FIG. 9  is a flow diagram of another method disclosed herein, which is schematically represented in  FIG. 10 . The same reference numbers will be used for the same particles for clarity. In step  500 , the coating precursor  104   p  is lithiated to produce coating particles  104  having the following formula: Li a Ni b Mn c Co d O 2 , wherein 0.95≤a≤1.5, 0≤b≤0.35, 0≤c≤1.0, 0≤d≤1.0 and b+c+d=1. The base precursor  102   p  is lithiated in step  502  to produce base particles  102  having the following formula: Li α Ni x M y Co z O 2 , wherein 0.95≤α≤1.5, 0.6≤x≤1.0, 0≤y≤0.5, 0≤z≤0.5; x+y+z=1; and M is one of Mn and Al. The cathode active material  100  is produced in step  504  by coating the base particles  102  with the coating particles  104 . 
     In some embodiments, the method further comprises coating the cathode active material  100  with the metal oxide, the metal fluoride or the metal phosphate, as shown in optional step  506  in  FIG. 9 . 
     In some embodiments, the method further comprises doping one or both of the base particles  102  and the coating particles  104  with the dopants discussed herein. In some embodiments, only the base particles  102  are doped. In some embodiments, only the coating particles  104  are doped. In some embodiments, both the base particles  102  and the coating particles  104  are doped. 
     EXAMPLES 
     A cathode was prepared with 90 wt. % active material, 5 wt. % binder and 5 wt. % carbon. The anode was prepared with graphite from ATL Gen 4 (Zichen G1). The ratio of anode to cathode material (N:P)=1.05-1.11, and the electrolyte was 1.2 M LiPF6 in ethylenecarbonate (EC) and ethylmethylcarbonate (EMC), EC:EMC (3:7 by wt.)+1 wt. % vinylene carbonate+2 wt. % 1.3-propane sultone. 
     For the following examples, the charge capacity was measured by charging the cell to 4.3 V using a rate of 0.1 C followed by a CVC step to C/40. The discharge capacity and average voltage were measured by discharging the cell to 2.5 V at a rate of 0.1 C. The first coulombic efficiency is the ratio of the discharge and charge capacities. The gravimetric energy density is the discharge capacity multiplied by the average discharge voltage and the volumetric energy density is the gravimetric energy density multiplied by the pellet density. 
     Example 1 
     A representative cathode active material was produced with a base particle of Li 1.02 Ni 0.8 Co 0.1 Mn 0.1 O 2  having a D50 particle diameter of 15 μm and a coating material of Li 1.01 Co 0.96 Mn 0.04 O 2  having a D50 particle diameter of 0.17 μm. The coating material was 4 wt. % of the cathode active material. The elemental analysis of the cathode active material was Li 1.02 Ni 0.76 Co 0.14 Mn 0.1 O 2 . The cathode active material was coated with 1000 ppm Al 2 O 3 .  FIG. 11  is an SEM image of a cross section of a cathode active material particle. 
     As shown in Table 1, the pellet density of the cathode active material is 3.49 g/cc, greater than the pellet density of the base particle alone. The volumetric energy density is 2651 Wh/L, also greater than the volumetric energy density realized with the base particle material without the low-nickel lithium-containing coating. The first coulombic efficiency is greater for the cathode active material than for the base particle material alone, indicating an increase in the reversible capacity when cathode active material is used. The discharge capacity of the cathode active material is unaffected at 197 mAh/g. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Cathode Active 
                   
               
               
                 Description 
                 Material 
                 Base particle 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Nickel, mol. % 
                 76.0 
                 80.0 
               
               
                 Coating nickel mol. % = 0 
               
               
                 Coating, ppm 
                 Al 2 O 3 , 1000 ppm 
               
               
                 Volumetric Energy Density at 
                 2651 
                 2582 
               
               
                 4.3 V, Wh/L 
               
               
                 Gravimetric Energy Density at 
                 761 
                 761 
               
               
                 4.3 V, mWh/g 
               
               
                 Charge Capacity, mAh/g 
                 221 
                 225 
               
               
                 (0.1 C, CVC until C/40) 
               
               
                 Discharge Capacity, mAh/g 
                 197 
                 197 
               
               
                 (0.1 DC to 2.5 V) 
               
               
                 1st Coulombic Efficiency 
                 89.3 
                 87.5 
               
               
                 (0.1 C/0.1 DC) to 4.3 V, % 
               
               
                 Average Discharge Voltage, 
                 3.86 
                 3.86 
               
               
                 0.1 C/0.1 DC, 4.3 V to 2.5 V, (V) 
               
               
                 Pellet Density, g/cc (200 MPa 
                 3.49 
                 3.39 
               
               
                 unloaded) 
               
               
                 PSD: d50, microns 
                 13 
                 15 
               
               
                 BET Surface Area, m 2 /g 
                 0.38 
                 0.24 
               
               
                   
               
            
           
         
       
     
       FIGS. 12A and 12B  are graphs of the thermal runaway of each of the cathode active material and the base particle material, respectively. As shown, the thermal runaway is delayed by approximately 3° C. when using the cathode active material rather than using the base particle material alone, illustrating the increased thermal stability of the cathode active material when compared to the base particle material alone. Table 2 lists the thermal runaway onset temperature for three upper cutoff voltages, as well as the discharge capacity at the three upper cutoff voltages for each of the cathode active material and the base particle material. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Material 
                 Cutoff voltage 
                 Capacity (mAh/g) 
                 T onset  (° C.) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Cathode active 
                 4.3 V 
                 196 
                 240 
               
               
                 material 
                 4.4 V 
                 205 
                 234 
               
               
                   
                 4.5 V 
                 213 
                 231 
               
               
                 Base particle material 
                 4.3 V 
                 192 
                 237 
               
               
                   
                 4.4 V 
                 200 
                 232 
               
               
                   
                 4.5 V 
                 210 
                 227 
               
               
                   
               
            
           
         
       
     
       FIGS. 13-17  are graphs of additional testing results of the materials in Example 1, showing the improved energy retention and reduced capacity fade realized with the cathode active material having the high-nickel base with low-nickel lithium containing coating. Each of  FIGS. 13-16  include data for a baseline base particle that has not been recalcined, a recalcined base particle that has been calcined at 700° C., and the cathode active material that has been calcined at 700° C.  FIG. 13  shows the slower decline in energy retention versus cycle number for the cathode active material when compared to either the baseline or recalcined base particle material.  FIG. 14  shows the reduction in capacity degradation as a function of cycle number when the cathode active material is used.  FIG. 15  shows the slow-down in the growth of direct current resistance (DCR) for the cathode active material versus either the base or the recalcined base particle material.  FIG. 16  shows the improved retention of average discharge voltage as a function of cycle number for the cathode active material when compared to the base particle material alone, both baseline and recalcined.  FIG. 17  is a charge/discharge profile for the cathode active material of Example 1. As shown, the cathode active material delivers about 219 mAh/g charge capacity and 200 mAh/g discharge capacity with an average discharge voltage of 3.72 V. 
     There is significant improvement in cycle stability when the cathode active material is used when compared to the base particle material alone and the recalcined base particle material alone. The cycle life (defined as reaching 80% of the beginning of life energy) nearly doubles for the cathode active material, from 180 cycles (200 cycles for the recalcined) to 350 cycles compared to the base particle material alone. 
       FIGS. 18 and 19  compare the cathode active material of Example 1 with the coating particles as 2 wt. % of the cathode active material and 4 wt. % of the cathode active material. These active cathode materials, both calcined at 700° C., are compared to the baseline base particle material alone as well as the recalcined base particle material alone.  FIG. 18  compares the capacity degradation as cycles increase, with each of the cathode active materials showing reduced degradation than either the baseline or recalcined base particle material alone.  FIG. 19  shows the increase in energy retention at 25 cycles for each of the cathode active materials compared to each of the baseline and recalcined base particle materials. The energy retention at 25 cycles for the 2 wt. % coated cathode active material and the 4 wt. % coated cathode active material is 93.8% for both, while the energy retention at 25 cycles for the baseline base particle material is 89.9%. 
     Example 2 
     Another representative cathode active material was produced with a base particle doped with 1% Mg with a composition of Li 1.02 Ni 0.94 Co 0.02 Mn 0.03 Mg 0.01 O 2  having a D50 particle diameter of 18 μm coated with a coating material of Li 1.01 Co 0.96 Mn 0.04 O 2  having a D50 particle diameter of 0.17 μm. The coating material was 4 wt. % of the cathode active material. The elemental analysis of the cathode active material was Li 1.03 Ni 0.90 Co 0.06 Mn 0.03 Mg 0.01 O 2 . The cathode active material was coated with 1000 ppm Al 2 O 3 . 
     As shown in Table 3, the pellet density of the cathode active material is 3.41 g/cc, greater than the pellet density of the base particle alone. The first coulombic efficiency is greater for the cathode active material than for the base particle material alone, indicating an increase in the reversible capacity when the cathode active material is used. The discharge capacity of the cathode active material is greater than that for the base particle material alone, 205 mAh/g versus 202 mAh/g. The volumetric energy density is 2688 Wh/L, also greater than the volumetric energy density realized with the base particle material without the coating. 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Cathode Active 
                   
               
               
                 Description 
                 Material 
                 Base particle 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Nickel, mol. % 
                 90.0 
                 94.0 
               
               
                 Coating nickel mol. % = 0 
               
               
                 Dopant 
                   
                 1% Mg 
               
               
                 Coating, ppm 
                 Al 2 O 3 , 1000 ppm 
               
               
                 Volumetric Energy Density at 
                 2688 
                 2618 
               
               
                 4.3 V, Wh/L 
               
               
                 Gravimetric Energy Density at 
                 787 
                 778 
               
               
                 4.3 V, mWh/g 
               
               
                 Charge Capacity, mAh/g 
                 235 
                 236 
               
               
                 (0.1 C, CVC until C/40) 
               
               
                 Discharge Capacity, mAh/g 
                 205 
                 202 
               
               
                 (0.1 DC to 2.5 V) 
               
               
                 1st Coulombic Efficiency 
                 87.2 
                 85.8 
               
               
                 (0.1 C/0.1 DC) to 4.3 V, % 
               
               
                 Average Discharge Voltage, 
                 3.84 
                 3.84 
               
               
                 0.1 C/0.1 DC, 4.3 V to 2.5 V, (V) 
               
               
                 Pellet Density, g/cc (200 MPa 
                 3.41 
                 3.37 
               
               
                 unloaded) 
               
               
                 PSD: d50, microns 
                 17 
                 18 
               
               
                 BET Surface Area, m 2 /g 
                 0.26 
                 0.28 
               
               
                   
               
            
           
         
       
     
       FIG. 20  is a graph of the thermal runaway of each of the cathode active material and the base particle material. As shown, the thermal runaway is delayed by approximately 4° C. when using the cathode active material rather than using the base particle material alone, illustrating the increased thermal stability of the cathode active material when compared to the base particle material alone. 
     Example 3 
     Another representative cathode active material was produced with a base particle having a composition of Li 1.02 Ni 0.89 Co 0.1 Al 0.01 O 2  with a D50 particle diameter of 22 μm coated with a coating material of Li 1.01 Co 0.96 Mn 0.04 O 2  having a D50 particle diameter of 0.17 μm. The coating material was 4 wt. % of the cathode active material. The elemental analysis of the cathode active material was Li 0.99 Ni 0.85 Co 0.12 Al 0.01 O 2 . The cathode active material was coated with 1000 ppm Al 2 O 3 . 
     As shown in Table 4, the pellet density of the cathode active material is 3.48 g/cc, unchanged from the pellet density of the base particle alone. The first coulombic efficiency is greater for the cathode active material than for the base particle material alone, indicating an increase in the reversible capacity when the cathode active material is used. 
     
       
         
           
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                   
                 Cathode Active 
                   
               
               
                 Description 
                 Material 
                 Base particle 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Nickel, mol. % 
                 85.0 
                 89.0 
               
               
                 Coating nickel mol. % = 0 
               
               
                 Coating, ppm 
                 Al 2 O 3 , 1000 ppm 
               
               
                 Volumetric Energy Density at 
                 2623 
                 2674 
               
               
                 4.3 V, Wh/L 
               
               
                 Gravimetric Energy Density at 
                 754 
                 769 
               
               
                 4.3 V, mWh/g 
               
               
                 Charge Capacity, mAh/g 
                 228 
                 233 
               
               
                 (0.1 C, CVC until C/40) 
               
               
                 Discharge Capacity, mAh/g 
                 197 
                 200 
               
               
                 (0.1 DC to 2.5 V) 
               
               
                 1st Coulombic Efficiency 
                 86.0 
                 85.7 
               
               
                 (0.1 C/0.1 DC) to 4.3 V, % 
               
               
                 Average Discharge Voltage, 
                 3.84 
                 3.84 
               
               
                 0.1 C/0.1 DC, 4.3 V to 2.5 V, (V) 
               
               
                 Pellet Density, g/cc (200 MPa 
                 3.48 
                 3.48 
               
               
                 unloaded) 
               
               
                 PSD: d50, microns 
                 23 
                 22 
               
               
                 BET Surface Area, m 2 /g 
                 0.20 
                 0.21 
               
               
                   
               
            
           
         
       
     
       FIG. 21  is a graph of the thermal runaway of each of the cathode active material and the base particle material. As shown, the thermal runaway is delayed by approximately 5° C. when using the cathode active material rather than using the base particle material alone, illustrating the increased thermal stability of the cathode active material when compared to the base particle material alone. 
     There is significant improvement to the cycle life (defined as reaching 80% of the beginning of life energy) when the cathode active material is used compared to the base particle material alone and the recalcined base particle material alone, from 190 cycles (325 cycles for the recalcined) to 500 cycles.  FIGS. 22-25  are graphs of additional testing results of the materials in Example 3. Each of  FIGS. 22-25  include data for a baseline base particle that has not been recalcined, a recalcined base particle that has been calcined at 700° C., and the cathode active material that has been calcined at 700° C.  FIG. 22  shows the slower decline in energy versus cycle number for the cathode active material when compared to either the baseline or recalcined base particle material.  FIG. 23  shows the reduction in capacity degradation as a function of cycle number when the cathode active material is used.  FIG. 24  shows the slow-down in the growth of direct current resistance (DCR) for the cathode active material versus either the base or the recalcined base particle material.  FIG. 25  shows the improved retention of average discharge voltage as a function of cycle number for the cathode active material when compared to the base particle material alone, both baseline and recalcined. 
     Example 4 
     Another representative cathode active material was produced with a base particle having a composition of Li 1.02 Ni 0.6 Co 0.2 Mn 0.2 O 2  coated with a coating material of Li 1.01 Co 0.96 Mn 0.04 O 2  having a D50 particle diameter of 0.17 μm. The coating material was 4 wt. % of the cathode active material. The elemental analysis of the cathode active material was Li 0.97 Ni 0.58 Co 0.23 Mn 0.19 O 2 . The cathode active material was coated with 1000 ppm Al 2 O 3 . 
     As shown in Table 5, the first coulombic efficiency is greater for the cathode active material than for the base particle material alone, indicating an increase in the reversible capacity when cathode active material is used. The discharge capacity increased from 159 mAh/g to 168 mAh/g. 
     
       
         
           
               
               
               
             
               
                 TABLE 5 
               
               
                   
               
               
                   
                 Cathode Active 
                   
               
               
                 Description 
                 Material 
                 Base particle 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Nickel, mol. % 
                 58.0 
                 60.0 
               
               
                 Coating nickel mol. % = 0 
               
               
                 Coating, ppm 
                 Al 2 O 3 , 1000 ppm 
               
               
                 Gravimetric Energy Density at 
                 644 
                 609 
               
               
                 4.3 V, mWh/L 
               
               
                 Charge Capacity, mAh/g 
                 193 
                 190 
               
               
                 (0.1 C., CVC until C/40) 
               
               
                 Discharge Capacity, mAh/g 
                 168 
                 159 
               
               
                 (0.1 DC to 2.5 V) 
               
               
                 1st Coulombic Efficiency 
                 87.0 
                 83.7 
               
               
                 (0.1 C./0.1 DC) to 4.3 V, % 
               
               
                 Average Discharge Voltage, 
                 3.84 
                 3.82 
               
               
                 0.1 C./0.1 DC, 4.3 V to 2.5 V, (V) 
               
               
                   
               
            
           
         
       
     
       FIG. 26  is a charge/discharge profile for both the base particle alone calcined at 700° C. and the cathode active material calcined at 700° C.  FIG. 27  shows specific capacity versus cycle number for both the base particle alone calcined at 700° C. and the cathode active material calcined at 700° C. The reduction in capacity degradation as a function of cycle number for the cathode active material, as well as the increase in the capacity irreversibility in the first cycle, are illustrated. 
     Example 5 
     Another representative cathode active material was produced with a base particle having a composition of Li 1.02 Ni 0.82 Co 0.11 Mn 0.02 O 2  with a D50 particle diameter of 19 μm coated with a coating material of Li 2 MnO 3 . The coating material was 4 wt. % of the cathode active material. The elemental analysis of the cathode active material was Li 1.01 Ni 0.81 Co 0.11 Mn 0.08 O 2 . The cathode active material was coated with 1000 ppm Al 2 O 3 .  FIG. 28  is an SEM image of a cross section of a cathode active material particle of Example 5. 
     As shown in Table 6, the pellet density of the cathode active material is 3.60 g/cc, increased from the pellet density of 3.54 g/cc of the base particle alone. The first coulombic efficiency is greater for the cathode active material than for the base particle material alone, indicating an increase in the reversible capacity when the cathode active material is used. The discharge capacity increases from 204 mAh/g for the base particle to 209 mAh/g for the cathode active material and volumetric energy density increased form 2775 Wh/l to 2876 Wh/L. 
     
       
         
           
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                   
                 Cathode Active 
                   
               
               
                 Description 
                 Material 
                 Base particle 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Nickel, mol. % 
                 81.0 
                 82.0 
               
               
                 Coating nickel mol. % = 0 
               
               
                 Coating, ppm 
                 Al 2 O 3 , 1000 ppm 
               
               
                 Volumetric Energy Density at 
                 2876 
                 2775 
               
               
                 4.3 V, Wh/L 
               
               
                 Gravimetric Energy Density at 
                 799 
                 784 
               
               
                 4.3 V, mWh/g 
               
               
                 Charge Capacity, mAh/g 
                 227 
                 226 
               
               
                 (0.1 C., CVC until C/40) 
               
               
                 Discharge Capacity, mAh/g 
                 209 
                 204 
               
               
                 (0.1 DC to 2.5 V) 
               
               
                 1st Coulombic Efficiency 
                 91.9 
                 90.4 
               
               
                 (0.1 C./0.1 DC) to 4.3 V, % 
               
               
                 Average Discharge Voltage, 
                 3.83 
                 3.84 
               
               
                 0.1 C./0.1 DC, 4.3 V to 2.5 V, (V) 
               
               
                 Pellet Density, g/cc (200 MPa 
                 3.60 
                 3.54 
               
               
                 unloaded) 
               
               
                 PSD: d50, microns 
                 20 
                 19 
               
               
                 BET Surface Area, m 2 /g 
                 0.42 
                 0.12 
               
               
                   
               
            
           
         
       
     
     The foregoing descriptions of various embodiments have been presented only for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art.

Metadata:
Filing Date: 20170728
Publication Date: 20200303
Grant Date: 20200303
Priority Date: 20160802
Inventors: WU, HUIMING
DAI, HONGLI
LIN, CHI-KAI
STROBRIDGE, Fiona C.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01M4/505", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/366", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M4/485", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2004/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M2004/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M4/505", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0525", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/5825", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0525", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/485", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/525", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/366", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M2004/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M4/525", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/485", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/5825", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M4/366", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M4/525", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0525", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2004/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M4/505", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2004/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02E60/10", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 59558521