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US-20260128283-A1 - LMFP COMPOSITE POSITIVE ELECTRODE PARTICLE

US20260128283A1US 20260128283 A1US20260128283 A1US 20260128283A1US-20260128283-A1

Abstract

An LMFP composite positive electrode particle, which is used in a positive electrode of a solid-state or semi-solid battery. The composite positive electrode particle includes an LMFP particle and a conductive layer coated on an outer surface of the LMFP particle. The conductive layer includes a plurality of carbon agglomerates, lithium ion conductor particles. The carbon agglomerates are formed by a dehydration reaction of carbohydrates, water-soluble fibers or amino acid polymers. The lithium ion conductor particles are formed by a first oxide or phosphate capable of conducting lithium ions, or by a second oxide with a garnet structure or a perovskite structure.

Inventors

  • ZHI FENG LUO

Assignees

  • ZHI FENG LUO

Dates

Publication Date
20260507
Application Date
20241107

Claims (15)

  1. 1 . An LMFP composite positive electrode particle; the composite positive electrode particle being used in a positive electrode of a solid-state or semi-solid battery; the composite positive electrode particle comprising: an LMFP particle; a conductive layer coated on an outer surface of the LMFP particle; and the conductive layer including a plurality of carbon agglomerates and a plurality of lithium ion conductor particles; wherein the carbon agglomerates are formed by a dehydration reaction of carbohydrates, or are formed by carbon skeletons and functional groups formed by a dehydration reaction of water-soluble fibers, or are formed by carbon skeletons with straight chains or side chains containing doping elements by a dehydration reaction of amino acid polymers; wherein the lithium ion conductor particles are dispersed within the conductive layer, or near an outer side of the conductive layer, or near the outer surface of the LMFP particle; and wherein each of the lithium ion conductor particles is formed by a first oxide or phosphate capable of conducting lithium ions, or is formed by a second oxide with a garnet structure or a perovskite structure.
  2. 2 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein the organic compound is selected from monosaccharide, disaccharide, oligosaccharide and polysaccharide.
  3. 3 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein a lithium ion conductivity of the first oxide or phosphate is higher than 10 −5 S/cm (Siemens per centimeter); and the first oxide or phosphate is selected from LATP (lithium aluminum titanium phosphate) with a NASICON (sodium (Na) super ionic conductor) structure, LAGP (lithium aluminium germanium phosphate), and lithiophosphate (Li 3 PO 4 ).
  4. 4 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein the second oxide with the garnet structure or the perovskite structure is selected from LLZO (Li 7 La 3 Zr 2 O 12 , lithium lanthanum zirconium oxide) and LLTO (lithium lanthanum titanium oxide).
  5. 5 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein a D50 (mass-median-diameter, MMD) value of the LMFP particle is less than 1 μm; and the LMFP particle is a polymer of monocrystalline materials or microcrystalline particles.
  6. 6 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein the LMFP particle is formed by LMFP (lithium manganese iron phosphate, LiMn x Fe 1-x PO 4 , 0.1≤x≤0.8) or LMFP doped with at least one metal.
  7. 7 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein the carbon agglomerates are formed by a compound including carbon, nitrogen, fluorine, phosphorus and sulfur; and the nitrogen, fluorine, phosphorus and sulfur are doped to the carbon.
  8. 8 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein an outer surface of each of the lithium ion conductor particles is further coated by a borate layer to cause that the lithium ion conductor particles form a plurality of lithium ion composite conductor particles; and the lithium ion composite conductor particles on the LMFP particle form a continuous layer structure or a discontinuously dispersed structure or an island-shaped structure.
  9. 9 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein a thickness of the conductive layer is less than or equal to 200 nm; and a size of each of the lithium ion conductor particles is less than or equal to 200 nm.
  10. 10 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein each of the lithium ion conductor particles is formed by at least one of LLZO (Li 7 La 3 Zr 2 O 12 ), Ga-LLZO (gallium-doped LLZO), Cu-LLZO (copper-doped LLZO), Ta-LLZO (tantalum-doped LLZO), Sr-LLZO (strontium-doped LLZO) and Al-LLZO (aluminum-doped LLZO).
  11. 11 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein each of the lithium ion conductor particles is formed by Cu a , X b -LLZO, which is LLZO doped with copper (Cu) and a metal X, wherein X is selected from gallium (Ga), tantalum (Ta), strontium (Sr), barium (Ba) and aluminum (Al), and a>0 and b>0.
  12. 12 . The LMFP composite positive electrode particle as claimed in claim 11 , wherein a+b=0.25˜0.8 and a>0.1.
  13. 13 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein each of the lithium ion conductor particles is formed by LAGP (lithium aluminium germanium phosphate) or LATP (lithium aluminum titanium phosphate); the LAGP or LATP is selected from Li 1+x Al x A 2-x (PO 4 ) 3 or Li 1+x+y Al x A 2−x−y−z M y N z (PO 4 ) 3 , wherein 0.1≤x≤0.8,0≤y≤0.2, 0≤z≤0.2, A is germanium (Ge) or titanium (Ti), M is trivalent cation, and N is tetravalent cation.
  14. 14 . The LMFP composite positive electrode particle as claimed in claim 1 , wherein an outer surface of the composite positive electrode particle is coated by a carbon material; and the carbon material includes a plurality of first carbon nanotubes and a plurality of nanoscale amorphous carbons; and a size of each of the nanoscale amorphous carbons is 10 nm to 40 nm.
  15. 15 . The LMFP composite positive electrode particle as claimed in claim 14 , wherein the first carbon nanotubes include a plurality of short chain carbon nanotubes and a plurality of long chain carbon nanotubes; a length of each of the short chain carbon nanotubes is 0.2 μm to 1 μm; and a length of each of the long chain carbon nanotubes is 1 μm to 3 μm.

Description

FIELD OF THE INVENTION The present invention is related to a positive electrode material for a battery, and in particular to an LMFP composite positive electrode particle. BACKGROUND OF THE INVENTION A typical battery includes a positive electrode and a negative electrode. A cathode of the battery is the positive electrode inside the battery. The positive electrode of a solid-state or semi-solid battery includes a positive electrode substrate and a positive electrode slurry layer. The positive electrode slurry layer includes a positive electrode slurry and a plurality of positive electrode particles. The positive electrode particles must be either additionally conductive or electrically conductive to allow free electrons to migrate through the positive electrode slurry without consuming too much energy due to internal resistance. Material of the positive electrode particles may be LMFP (lithium manganese iron phosphate), which has a better working voltage performance than LFP (lithium iron phosphate), releases higher energy density, is inexpensive, and is hydrophobic. However, LMFP has a poor charge-discharge rate performance and a lower lithium ion conductivity and electrical conductivity, and it is prone to deterioration under prolonged battery use. Although there are many ways to increase the lithium ion conductivity of positive electrode particles, the electrical conductivity is still insufficient for practical use. Therefore, the present invention desires to provide a novel invention to increase the electrical capacity and electrical conductivity of positive electrode of solid-state or semi-solid battery. SUMMARY OF THE INVENTION Accordingly, for improving above mentioned defects in the prior art, the object of the present invention is to provide an LMFP composite positive electrode particle, wherein the LMFP particle is coated by a conductive layer to increase the overall performance. The cost of LMFP is lower than the ternary oxide and the charge and discharge performance of LMFP can be applied to a specific range of applications. The conductive layer on the outer surface of the LMFP particle compensates for the lower conductivity of LMFP, and the LMFP particle are also coated with lithium ion conductor particles to enhance the overall lithium ion conductivity and electrical conductivity, resulting in a better battery performance. To achieve above object, the present invention provides an LMFP composite positive electrode particle; the composite positive electrode particle being used in a positive electrode of a solid-state or semi-solid battery; the composite positive electrode particle comprising: an LMFP particle; a conductive layer coated on an outer surface of the LMFP particle; and the conductive layer including a plurality of carbon agglomerates and a plurality of lithium ion conductor particles; wherein the carbon agglomerates are formed by a dehydration reaction of carbohydrates, or are formed by carbon skeletons and functional groups formed by a dehydration reaction of water-soluble fibers, or are formed by carbon skeletons with straight chains or side chains containing doping elements by a dehydration reaction of amino acid polymers; wherein the lithium ion conductor particles are dispersed within the conductive layer, or near an outer side of the conductive layer, or near the outer surface of the LMFP particle; wherein each of the lithium ion conductor particles is formed by a first oxide or phosphate capable of conducting lithium ions, or is formed by a second oxide with a garnet structure or a perovskite structure. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-section view showing the structure of the composite positive electrode particle of the present invention. FIG. 2 is a schematic view showing an application of the present invention. FIG. 3 is a schematic view showing the full structure and a partial structure of the composite positive electrode particle of the present invention. FIG. 4 is a schematic view showing the carbon-material-coated composite positive electrode particle of the present invention. FIG. 5 is a schematic view showing the lithium ion composite conductor particle of the present invention. FIG. 6 is a schematic view showing the structure of another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims. With reference to FIGS. 1 to 6, the present invention provides an LMFP composite positive electrode particle 200, which is used in a positive (+) electrode 100 of a solid-state or semi-solid battery. The positi