Single-crystal cathode material and method for manufacturing the same, sodium-ion battery

Abstract

The single-crystal granules of the single-crystal cathode material have a specific granule size distribution, the single-crystal cathode material has a high pressure density, and in addition, a high Young's modulus, which allows it to withstand higher rolling pressure during battery manufacturing, thereby increasing the volumetric energy density of the lithium-ion battery equipped with the cathode material. The present invention relates to the technical field of sodium-ion batteries, and more particularly to a single-crystal cathode material, a method for manufacturing the same, and a sodium-ion battery. Size distribution of single-crystal granules of the single-crystal cathode material B 90 =(P 90 -P 10 ) / P 50 However, 0.9 ≤ B 90 The condition ≤ 1.4 is satisfied. The Young's modulus E of the positive electrode material, measured using an atomic force microscope, satisfies the condition 100 GPa ≤ E ≤ 200 GPa.

Claims

1. A single-crystal cathode material, wherein the size distribution B of the single-crystal granules of the single-crystal cathode material. ９０ = (P ９０ -P １０ ) / P ５０ However, 0.9 ≤ B ９０ Satisfying ≤ 1.4, Here, P １０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% in the SEM image of the cathode material, P ５０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 50% in the SEM image of the cathode material, P ９０ This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample that reached 90% in the SEM image of the cathode material. The Young's modulus E of the positive electrode material, as measured using an atomic force microscope, satisfies 100 GPa ≤ E ≤ 200 GPa. A single-crystal cathode material characterized by the following features.

2. 1 ≤ B ９０ ≤ 1.3, and Preferably, 120 GPa ≤ E ≤ 200 GPa, Preferably, 1 μm ≤ P ５０ ≤ 2 μm, Preferably, 1.3 μm ≤ P ５０ The size is ≤ 1.7 μm. The single-crystal cathode material according to feature 1.

3. The coverage X of the positive electrode material, as measured by SEM, satisfies 5% ≤ X, and preferably 5% ≤ X ≤ 30%. Preferably, the residual stress of the positive electrode material measured by XRD is 0 to 0.2%. Preferably, the median particle size D of the positive electrode material is measured by a particle size analyzer. ５０ However, 2 μm ≤ D ５０ Satisfying ≤ 6 μm, Preferably, after pressurization at 400 MPa, the particle size change rate ΔD of the positive electrode material is measured with a particle size analyzer. １０ = D １０ -D' １０ However, △D １０ The condition ≤ 0.2 μm is satisfied, where D １０ D' represents the particle size before pressurization. １０ This represents the particle size after pressurization. Preferably, the pressure density of the positive electrode material is 3.3–3.7 g / cm³. ３ That is, The single-crystal cathode material according to claim 1 or 2, characterized by the above.

4. Having the composition shown in formula I, Li １＋ａ (Ni ｘ Mn ｙ Co ｚ G ｂ )M ｃ O ２ Formula I Here, 0 ≤ a ≤ 0.2, 0 < b ≤ 0.05, 0 < c ≤ 0.05, 0.4 ≤ x < 1, 0 < y < 0.5, 0 ≤ z < 0.5, M is selected from at least one of B, Nb, Co, Mo, W, Si, Mg, and Al. G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si. A single-crystal cathode material according to any one of claims 1 to 3.

5. S1, a step of mixing a nickel-cobalt-manganese precursor and a lithium source with an additive containing a selectable element G to obtain a mixture I, S2, a step of first sintering mixture I in an oxygen-containing atmosphere and crushing it to obtain a semi-finished product II of single-crystal cathode material, S3, a step of mixing a semi-finished single-crystal cathode material II with a coating agent containing a selectable element M to obtain a mixture III, S4 includes the step of sintering mixture III a second time in an oxygen-containing atmosphere to obtain a single-crystal cathode material. Size distribution B of single crystal granules of single crystal cathode material under the action of crushing. ９０ = (P ９０ -P １０ ) / P ５０ However, 0.9 ≤ B ９０ Satisfying ≤ 1.4, Here, P １０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% in the SEM image of the cathode material, P ５０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 50% in the SEM image of the cathode material, P ９０ This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample that reached 90% in the SEM image of the cathode material. The aforementioned initial sintering has a sintering temperature of T / °C, and the time from 400°C to T in the heating step is t １ / h, and the time from T to 400°C in the cooling step is t ２ This includes the fact that / h, where t ２ ga [ln(T-400)] / t ２ Satisfying ≤ 1, A method for producing a single-crystal cathode material according to any one of claims 1 to 4.

6. 0 < t １ / t ２ The manufacturing method according to claim 5, characterized in that ≤ 1 and / or 800°C ≤ T ≤ 1000°C.

7. In step S1, the G element-containing additive is selected from at least one of an oxide of G, a hydroxide of G, and a carbonate of G. Preferably, element G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si. Preferably, G is E Ｇ－Ｏ Satisfying ≥ 500 kJ / mol, E Ｇ－Ｏ This is the G-O bond energy, Preferably, the doses of the nickel-cobalt-manganese precursor, the lithium source, and the G-containing additive are such that 1 ≤ n(Li) / [n(Ni) + n(Co) + n(Mn)] ≤ 1.2 and 0 ≤ n(G) / [n(Ni) + n(Co) + n(Mn)] ≤ 0.

05. The manufacturing method according to claim 5 or 6, characterized by the above.

8. The aforementioned M element is selected from at least one of B, Nb, Co, Mo, W, Si, Mg, and Al. Preferably, the amounts of the semi-finished product II of the single-crystal cathode material and the coating agent containing element M are 0 ≤ n(M) / [n(Ni) + n(Co) + n(Mn)] ≤ 0.

05. The manufacturing method according to any one of claims 5 to 7, characterized by...

9. The conditions for the second sintering include a sintering temperature of 300 to 800°C and a sintering time of 4 to 12 hours. The manufacturing method according to any one of claims 5 to 8, characterized by...

10. A lithium-ion battery characterized by containing the single-crystal cathode material described in any one of claims 1 to 4.

Images