MODIFIED TERNARY AND LITHIUM MANGANESE IRON PHOSPHATE COMPOSITE MATERIAL AND PREPARATION METHOD AND APPLICATION THEREOF

Abstract

The present disclosure relates to a modified ternary and lithium manganese iron phosphate composite material and a preparation method and an application thereof. The material includes a modified ternary material and a modified lithium manganese iron phosphate material that are composite; wherein the modified ternary material includes a ternary material, a ternary material double-layer cladding layer, and ternary material doped metal ions; the ternary material double-layer cladding layer includes a ternary material metal oxide layer and a ternary material cationic cladding layer; the modified lithium manganese iron phosphate material includes a lithium manganese iron phosphate material, a lithium manganese iron phosphate double-layer cladding layer, and lithium manganese iron phosphate doped metal ions; the lithium manganese iron phosphate double-layer cladding layer includes a lithium manganese iron phosphate metal oxide layer and a lithium manganese iron phosphate cationic cladding layer.

Claims

1. A modified ternary and lithium manganese iron phosphate composite material, comprising a modified ternary material and a modified lithium manganese iron phosphate material that are composite; wherein the modified ternary material comprises a ternary material, a ternary material double-layer cladding layer, and ternary material doped metal ions; the ternary material double-layer cladding layer comprises a ternary material metal oxide layer and a ternary material cationic cladding layer; the modified lithium manganese iron phosphate material comprises a lithium manganese iron phosphate material, a lithium manganese iron phosphate double-layer cladding layer, and lithium manganese iron phosphate doped metal ions; the lithium manganese iron phosphate double-layer cladding layer comprises a lithium manganese iron phosphate metal oxide layer and a lithium manganese iron phosphate cationic cladding layer.

2. The modified ternary and lithium manganese iron phosphate composite material according to claim 1, wherein a material of the ternary material metal oxide layer comprises titanium dioxide; a material of the ternary material cationic cladding layer comprises lithium titanate; the ternary material doped metal ions are titanium ions; a thickness of the ternary material double-layer cladding layer is 610 nm; a material of the lithium manganese iron phosphate metal oxide layer comprises titanium dioxide; a material of the lithium manganese iron phosphate cationic cladding layer comprises lithium titanate; the lithium manganese iron phosphate doped metal ions are titanium ions; a thickness of the lithium manganese iron phosphate double-layer cladding layer is 610 nm.

3. The modified ternary and lithium manganese iron phosphate composite material according to claim 1, wherein a composite mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is (01):1 and is not zero; a median particle size of the modified ternary and lithium manganese iron phosphate composite material is 215 km.

4. The modified ternary and lithium manganese iron phosphate composite material according to claim 3, wherein a material of the ternary material metal oxide layer comprises titanium dioxide; a material of the ternary material cationic cladding layer comprises lithium titanate; the ternary material doped metal ions are titanium ions; a thickness of the ternary material double-layer cladding layer is 610 nm; a material of the lithium manganese iron phosphate metal oxide layer comprises titanium dioxide; a material of the lithium manganese iron phosphate cationic cladding layer comprises lithium titanate; the lithium manganese iron phosphate doped metal ions are titanium ions; a thickness of the lithium manganese iron phosphate double-layer cladding layer is 610 nm.

5. A method for preparing the modified ternary and lithium manganese iron phosphate composite material according to claim 1, comprising: providing the modified ternary material and the modified lithium manganese iron phosphate material; and mixing the modified ternary material and the modified lithium manganese iron phosphate material to obtain the modified ternary and lithium manganese iron phosphate composite material.

6. The method according to claim 5, wherein a preparation method of the modified lithium manganese iron phosphate material comprises: mixing a lithium manganese iron phosphate precursor, a lithium source, and a titanium source, spray drying and granulating, calcining under a protective atmosphere, and obtaining the modified lithium manganese iron phosphate material; the titanium source comprises titanium trioxide; a mass of the titanium source is 14 wt % of a mass of the lithium manganese iron phosphate precursor; the protective atmosphere is an inert gas atmosphere; a temperature of the calcining is 700800 C.; a duration of the calcining is 810 h; the calcining is further followed by treatments of crushing, sieving, and demagnetizing.

7. The method according to claim 5, wherein a preparation method of the modified ternary material comprises: mixing a ternary precursor, a lithium source, and a titanium source, and sintering to obtain the modified ternary material; a molar ratio of Ni:Co:Mn in the ternary precursor is 1:1:19.5:0.25:0.25; the lithium source comprises any one or a combination of at least two of lithium hydroxide, lithium carbonate, lithium nitrate, or lithium acetate; the titanium source comprises titanium trioxide; a mass of the titanium source is 14 wt % of a mass of the ternary precursor; a temperature of the sintering is 750950 C.; a duration of the sintering is 1015 h; the sintering is further followed by treatments of roller, jaw breaker, crushing, and demagnetization.

8. The method according to claim 7, wherein a preparation method of the modified lithium manganese iron phosphate material comprises: mixing a lithium manganese iron phosphate precursor, a lithium source, and a titanium source, spray drying and granulating, calcining under a protective atmosphere, and obtaining the modified lithium manganese iron phosphate material; the titanium source comprises titanium trioxide; a mass of the titanium source is 14 wt % of a mass of the lithium manganese iron phosphate precursor; the protective atmosphere is an inert gas atmosphere; a temperature of the calcining is 700800 C.; a duration of the calcining is 810 h; the calcining is further followed by treatments of crushing, sieving, and demagnetizing.

9. The method according to claim 5, wherein a median particle size of the modified ternary material is 520 m; a median particle size of the modified lithium manganese iron phosphate material is 15 m; the mixing comprises high-energy ball milling; a ball material ratio of the high-energy ball milling is (1020):1; a rotational speed of the high-energy ball milling is 15002000 rpm; a duration of the high-energy ball milling is 12 h; a mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is (01):1 and is not 0.

10. The method according to claim 6, wherein a median particle size of the modified ternary material is 520 m; a median particle size of the modified lithium manganese iron phosphate material is 15 m; the mixing comprises high-energy ball milling; a ball material ratio of the high-energy ball milling is (1020):1; a rotational speed of the high-energy ball milling is 15002000 rpm; a duration of the high-energy ball milling is 12 h; a mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is (01):1 and is not 0.

11. The method according to claim 7, wherein a median particle size of the modified ternary material is 520 m; a median particle size of the modified lithium manganese iron phosphate material is 15 m; the mixing comprises high-energy ball milling; a ball material ratio of the high-energy ball milling is (1020):1; a rotational speed of the high-energy ball milling is 15002000 rpm; a duration of the high-energy ball milling is 12 h; a mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is (01):1 and is not 0.

12. The method according to claim 8, wherein a median particle size of the modified ternary material is 520 m; a median particle size of the modified lithium manganese iron phosphate material is 15 m; the mixing comprises high-energy ball milling; a ball material ratio of the high-energy ball milling is (1020):1; a rotational speed of the high-energy ball milling is 15002000 rpm; a duration of the high-energy ball milling is 12 h; a mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is (01):1 and is not 0.

13. The method according to claim 5, wherein a material of the ternary material metal oxide layer comprises titanium dioxide; a material of the ternary material cationic cladding layer comprises lithium titanate; the ternary material doped metal ions are titanium ions; a thickness of the ternary material double-layer cladding layer is 610 nm; a material of the lithium manganese iron phosphate metal oxide layer comprises titanium dioxide; a material of the lithium manganese iron phosphate cationic cladding layer comprises lithium titanate; the lithium manganese iron phosphate doped metal ions are titanium ions; a thickness of the lithium manganese iron phosphate double-layer cladding layer is 610 nm.

14. The method according to claim 5, wherein a composite mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is (01):1 and is not zero; a median particle size of the modified ternary and lithium manganese iron phosphate composite material is 215 m.

15. The method according to claim 14, wherein a material of the ternary material metal oxide layer comprises titanium dioxide; a material of the ternary material cationic cladding layer comprises lithium titanate; the ternary material doped metal ions are titanium ions; a thickness of the ternary material double-layer cladding layer is 610 nm; a material of the lithium manganese iron phosphate metal oxide layer comprises titanium dioxide; a material of the lithium manganese iron phosphate cationic cladding layer comprises lithium titanate; the lithium manganese iron phosphate doped metal ions are titanium ions; a thickness of the lithium manganese iron phosphate double-layer cladding layer is 610 nm.

16. A battery, comprising the modified ternary and lithium manganese iron phosphate composite material according to claim 1.

17. The battery according to claim 16, wherein a material of the ternary material metal oxide layer comprises titanium dioxide; a material of the ternary material cationic cladding layer comprises lithium titanate; the ternary material doped metal ions are titanium ions; a thickness of the ternary material double-layer cladding layer is 610 nm; a material of the lithium manganese iron phosphate metal oxide layer comprises titanium dioxide; a material of the lithium manganese iron phosphate cationic cladding layer comprises lithium titanate; the lithium manganese iron phosphate doped metal ions are titanium ions; a thickness of the lithium manganese iron phosphate double-layer cladding layer is 610 nm.

18. The battery according to claim 16, wherein a composite mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is (01):1 and is not zero; a median particle size of the modified ternary and lithium manganese iron phosphate composite material is 215 km.

19. The battery according to claim 18, wherein a material of the ternary material metal oxide layer comprises titanium dioxide; a material of the ternary material cationic cladding layer comprises lithium titanate; the ternary material doped metal ions are titanium ions; a thickness of the ternary material double-layer cladding layer is 610 nm; a material of the lithium manganese iron phosphate metal oxide layer comprises titanium dioxide; a material of the lithium manganese iron phosphate cationic cladding layer comprises lithium titanate; the lithium manganese iron phosphate doped metal ions are titanium ions; a thickness of the lithium manganese iron phosphate double-layer cladding layer is 610 nm.

20. A cathode sheet, comprising the modified ternary and lithium manganese iron phosphate composite material according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 is a scanning electron micrograph diagram of a modified ternary material in Embodiment 1.

[0068] FIG. 2 is a scanning electron microscope diagram of a modified lithium manganese iron phosphate material in Embodiment 1.

[0069] FIG. 3 is a scanning electron microscope diagram of a modified ternary and lithium manganese iron phosphate composite material in Embodiment 1.

[0070] FIG. 4 is an XRD comparison diagram in Embodiment 1.

DETAILED DESCRIPTION

[0071] The technical solutions of the present disclosure are further described below in conjunction with the accompanying drawings and by way of specific embodiments. However, the following embodiments are only simple examples of the present disclosure and do not represent or limit the scope of the present disclosure, which is subject to the claims.

Embodiment 1

[0072] The embodiment provides a modified ternary and lithium manganese iron phosphate composite material, including a modified ternary material and a modified lithium manganese iron phosphate material that are composite with a mass ratio of 3:7, with a median particle size of 10 m.

[0073] The modified ternary material (with a scanning electron microscope diagram as shown in FIG. 1) includes an NCM523 ternary material, a ternary material double-layer cladding layer, and doped titanium dioxide; the ternary material double-layer cladding layer has a thickness of 8 nm and includes a titanium dioxide layer and a lithium titanate cationic cladding layer; the modified ternary material has a median particle size of 10 m.

[0074] The modified lithium manganese iron phosphate material (with a scanning electron microscope diagram as shown in FIG. 2) includes a lithium manganese iron phosphate material, a lithium manganese iron phosphate double-layer cladding layer, and doped titanium trioxide; the lithium manganese iron phosphate double-layer cladding layer has a thickness of 8 nm and includes a titanium dioxide layer and a lithium titanate cationic cladding layer; the modified lithium manganese iron phosphate material has a median particle size of 2.5 m.

[0075] The modified ternary and lithium manganese iron phosphate composite material is obtained by the following preparation method.

[0076] Mixing an NCM523 ternary precursor, lithium hydroxide, and titanium trioxide of 2.5 wt % by mass of the ternary precursor; sintering at 800 C. for 12 h; and obtaining the modified ternary material after treatments of roller, jaw breaking, crushing, and demagnetization.

[0077] Mixing a lithium manganese iron phosphate precursor, lithium hydroxide, and titanium trioxide of 2.5 wt % by mass of the lithium manganese iron phosphate precursor, spray drying and granulating, calcining at 750 C. for 9 h under argon gas atmosphere; and obtaining the modified lithium manganese iron phosphate material after treatments of crushing, sieving, and demagnetizing.

[0078] Mixing the modified ternary material and the modified lithium manganese iron phosphate material in a mass ratio of 3:7, performing high-energy ball milling for 1.5 h at a ball-to-material ratio of 15:1 and a rotational speed of 1800 rpm, and obtaining the modified ternary and lithium manganese iron phosphate composite material (with a scanning electron microscopy diagram as shown in FIG. 3).

[0079] EDS elemental testing of the resulting modified ternary and lithium manganese iron phosphate composite material shows that Ti element is uniformly distributed in the bulk phase of the material, indicating the presence of titanium doping.

[0080] Pure TiO.sub.2 and Ti.sub.2O.sub.3 are mixed with a lithium source, respectively, and sintered for the same amount of time under the experimental conditions of Embodiment. As shown in FIG. 4, the XRD test result of mixing and sintering TiO.sub.2 with the lithium source corresponds to the pure phase TiO.sub.2; the XRD test result of mixing and sintering Ti.sub.2O.sub.3 with the lithium source corresponds to the mixing of Li.sub.2TiO.sub.3 and TiO.sub.2, indicating that the double-layer cladding layer is composed of TiO.sub.2 and Li.sub.2TiO.sub.3.

Embodiment 2

[0081] The embodiment provides a modified ternary and lithium manganese iron phosphate composite material, including a modified ternary material and a modified lithium manganese iron phosphate material that are composite with a mass ratio of 1:1, with a median particle size of 2 m.

[0082] The modified ternary material includes an NCM523 ternary material, a ternary material double-layer cladding layer, and doped titanium trioxide; the ternary material double-layer cladding layer has a thickness of 6 nm and includes a titanium dioxide layer and a lithium titanate cationic cladding layer; the modified ternary material has a median particle size of 5 m.

[0083] The modified lithium manganese iron phosphate material includes a lithium manganese iron phosphate material, a lithium manganese iron phosphate double-layer cladding layer, and doped titanium trioxide; the lithium manganese iron phosphate double-layer cladding layer has a thickness of 6 nm and includes a titanium dioxide layer and a lithium titanate cationic cladding layer; the modified lithium manganese iron phosphate material has a median particle size of 1 m.

[0084] The modified ternary and lithium manganese iron phosphate composite material is obtained by the following preparation method.

[0085] Mixing an NCM523 ternary precursor, lithium carbonate, and titanium trioxide of 1 wt % by mass of the ternary precursor; sintering at 750 C. for 15 h; and obtaining the modified ternary material after treatments of roller, jaw breaking, crushing, and demagnetization.

[0086] Mixing a lithium manganese iron phosphate precursor, lithium carbonate, and titanium trioxide of 1 wt % by mass of lithium manganese iron phosphate precursor, spray drying and then granulating, calcining at 700 C. for 10 h under inert gas atmosphere; and obtaining the modified lithium manganese iron phosphate material after treatments of crushing, sieving, and demagnetizing.

[0087] Mixing the modified ternary material and the modified lithium manganese iron phosphate material in a mass ratio of 1:1, performing high-energy ball milling for 1 h at a ball-to-material ratio of 10:1 and a rotational speed of 2000 rpm, and obtaining the modified ternary and lithium manganese iron phosphate composite material.

Embodiment 3

[0088] The embodiment provides a modified ternary and lithium manganese iron phosphate composite material, including a modified ternary material and a modified lithium manganese iron phosphate material that are composite with a mass ratio of 2:8, with a median particle size of 15 m.

[0089] The modified ternary material includes an NCM523 ternary material, a ternary material double-layer cladding layer, and doped titanium trioxide; the ternary material double-layer cladding layer has a thickness of 10 nm and includes a titanium dioxide layer and a lithium titanate cationic cladding layer; the modified ternary material has a median particle size of 20 m.

[0090] The modified lithium manganese iron phosphate material includes a lithium manganese iron phosphate material, a lithium manganese iron phosphate double-layer cladding layer, and doped titanium trioxide; the lithium manganese iron phosphate double-layer cladding layer has a thickness of 10 nm and includes a titanium dioxide layer and a lithium titanate cationic casing layer; the modified lithium manganese iron phosphate material has a median particle size of 5 m.

[0091] The modified ternary and lithium manganese iron phosphate composite material is obtained by the following preparation method.

[0092] Mixing an NCM523 ternary precursor, lithium nitrate, and titanium trioxide of 4 wt % by mass of the ternary precursor; sintering at 950 C. for 10 h; and obtaining the modified ternary material after treatments of roller, jaw breaking, crushing, and demagnetization.

[0093] Mixing a lithium manganese iron phosphate precursor, lithium nitrate, and titanium trioxide of 4 wt % by mass of lithium manganese iron phosphate precursor, spray drying and then granulating, calcining at 800 C. for 8 h under inert gas atmosphere; and obtaining the modified lithium manganese iron phosphate material after treatments of crushing, sieving, and demagnetizing.

[0094] Mixing the modified ternary material and the modified lithium manganese iron phosphate material in a mass ratio of 2:8, performing high-energy ball milling for 2 h at a ball-to-material ratio of 20:1 and a rotational speed of 1500 rpm, and obtaining the modified ternary and lithium manganese iron phosphate composite material.

Embodiment 4

[0095] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that the composite mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is 2:1.

Embodiment 5

[0096] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that titanium trioxide is replaced with titanium dioxide of equal mass in the preparation method of the modified ternary material.

Embodiment 6

[0097] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that the addition amount of titanium trioxide in the preparation method of the modified ternary material is 0.5 wt %.

Embodiment 7

[0098] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that the addition amount of titanium trioxide in the preparation method of the modified ternary material is 4.5 wt %.

Embodiment 8

[0099] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that titanium trioxide is replaced with titanium dioxide of equal mass in the preparation method of the modified lithium manganese iron phosphate material.

Embodiment 9

[0100] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that the addition amount of titanium trioxide in the preparation method of the modified lithium manganese iron phosphate material is 0.5 wt %.

Embodiment 10

[0101] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that the addition amount of titanium trioxide in the preparation method of the modified lithium manganese iron phosphate material is 4.5 wt %.

Embodiment 11

[0102] The embodiment provides a ternary and lithium manganese iron phosphate composite material, and the difference with Embodiment 1 is that the preparation method of the ternary and lithium manganese iron phosphate composite material includes the following steps.

[0103] Mixing a ternary precursor and a lithium source, sintering at 800 C. for 12 h, and obtaining the modified ternary material after treatments of roller, jaw breaking, crushing, and demagnetization.

[0104] Mixing a lithium manganese iron phosphate precursor and lithium source, spray drying and then granulating, calcining at 750 C. for 9 h under inert gas atmosphere, and obtaining the modified lithium manganese iron phosphate material after treatments of crushing, sieving, and demagnetizing.

[0105] Mixing 2.5 wt % of titanium trioxide and the ternary material and lithium manganese iron phosphate material in a mass ratio of 3:7, and performing high-energy ball milling to obtain the modified ternary and lithium manganese iron phosphate composite material.

Comparative Example 1

[0106] The present comparative example provides a ternary and lithium manganese iron phosphate composite material, and the difference with the embodiments is that titanium trioxide is not added in the preparation method.

[0107] The ternary and lithium manganese iron phosphate composite material obtained from the above is used to make a cathode slurry in accordance with ratios of cathode material:SP:CNT:PVDF=97:0.4:0.5:2.1, which is coated on a 12 m carbon coated aluminum foil to obtain a cathode sheet; an anode slurry is made in accordance with ratios of graphite:SP:CMC:SBR=97:0.7:1.25:1.05, which is coated on an 8 m copper foil to obtain an anode sheet. The diaphragm is adopted with a model of 9+2+1 m. The electrolyte is EC:DEC:EMC=4:3:3, the additives account for 10% of the total mass, of which VC:PS:FEC:CHB=3:2:1:1, and the concentration of lithium hexafluorophosphate in the electrolyte is 1 mol/L. The cathode and anode sheets and the diaphragm are wound or laminated to obtain a bare battery cell, which is placed in an outer aluminum-plastic film to be assembled into a 2 Ah soft pack electric cell. The electrolyte is injected into the soft pack electric cell, and a soft pack lithium-ion battery is obtained, after treatments of aging, chemical formation, shaping, encapsulation and other processes, for testing.

[0108] The results are shown in Table 1.

TABLE-US-00001 TABLE 1 Energy 1 C, 200-week Capacity, density, cycling, capacity Test No. mAh/g Wh/kg retention rate/% Embodiment 1 158.0 200.0 98.5 Embodiment 2 161.2 204.0 97.1 Embodiment 3 159.6 202.0 97.6 Embodiment 4 161.5 204.4 92.5 Embodiment 5 156.9 198.6 93.8 Embodiment 6 156.6 198.2 94.5 Embodiment 7 156.4 197.9 94.9 Embodiment 8 156.6 198.2 93.5 Embodiment 9 157.3 199.1 95.1 Embodiment 10 157.6 199.4 95.7 Embodiment 11 155.9 197.3 93.8 Comparative 156.2 197.7 93.2 Example 1

[0109] The following conclusions are obtained from Table 1.

[0110] (1) From data of Embodiments 1-3 and Comparative Example 1, the ternary and lithium manganese iron phosphate composite material can contribute to a cathode material that takes into account the energy density and long-cycle performance; both the ternary material and the lithium manganese iron phosphate are modified by doping and cladding, which can make use of the synergistic effect of the doping and cladding to optimize the long-cycle performance of the cathode material.

[0111] (2) As can be seen from the comparison between Embodiment 4 and Embodiment 1, when the composite mass ratio of the modified ternary material and the modified lithium manganese iron phosphate material is not within the preferred range provided by the present disclosure, the resulting ternary and the lithium manganese iron phosphate composite material is not conducive to obtaining a cathode material that takes into account both the energy density and the long-cycle performance.

[0112] (3) As can be seen from the comparison between Embodiments 5-10 and Embodiment 1, when replacing titanium trioxide with other titanium sources, or when the addition amount of titanium trioxide is not within the preferred range provided by the present disclosure, it is not possible to realize the simultaneous modification of titanium doping and surface double-layer cladding by the one step of mixing and sintering, which affects the structure of the material from the surface to the interior and is unfavorable to the improvement of its cycling performance and energy density.

[0113] (4) As can be seen from the comparison between Embodiment 11 and Embodiment 1, when the composite is first carried out and then the cladding is carried out, the cladding layer is not uniform due to the close contact between the ternary material and the lithium manganese iron phosphate material, and the electrical properties of the material cannot be well improved.

[0114] In summary, the ternary and lithium manganese iron phosphate composite material in the present disclosure can contribute to a cathode material that takes into account the energy density and long-cycle performance; both the ternary material and the lithium manganese iron phosphate are modified by doping and cladding, which can make use of the synergistic effect of the doping and cladding to optimize the long-cycle performance of the cathode material.

[0115] The present disclosure illustrates the detailed features of the present disclosure by means of the above embodiments, but the present disclosure is not limited to the above detailed features, i.e., it does not mean that the present disclosure must rely on the above detailed features in order to be implemented. It should be clear to those skilled in the art that any improvement of the present disclosure, equivalent replacement of the selected components of the present disclosure, addition of auxiliary components, selection of specific implementations, etc., fall within the scope of the present disclosure.