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CN-116387507-B - Preparation method of high-compaction layered metal lithium compound

CN116387507BCN 116387507 BCN116387507 BCN 116387507BCN-116387507-B

Abstract

The invention provides a preparation method of a high-compaction layered metal lithium compound, which belongs to the technical field of lithium ion secondary battery materials, wherein the expression of the prepared high-compaction layered metal lithium compound is F1 x F2 y , the granularity is in bimodal distribution, F1 is a compound corresponding to a small particle size peak, and F2 is a compound corresponding to a large particle size peak. Firstly preparing precursors P1 and P2 of F1 and F2, wherein (D90-D10)/D50 is more than or equal to 0.1 and less than or equal to 0.8 and D100 P1 ≤D0 P2 by a batch method, then preprocessing P1 and P2 to prepare intermediates M1 and M2, wherein 1M 2 /g≤SSA≤5m 2 /g and 0.8 is more than or equal to SSA M1 /SSA M2 and less than or equal to 1.2, and finally mixing M1, M2 and N-containing compounds and simultaneously doping and sintering under the same sintering system. The preparation method is simple, low in cost and high in productivity, is suitable for large-scale industrial production, and the prepared high-compaction layered lithium metal compound has the advantages of good uniformity, low residual alkali, high compaction, high energy density, long cycle life and the like.

Inventors

  • LI WENJUAN
  • FANG SHENGTING
  • TIAN XINYONG
  • GAO YANBIN

Assignees

  • 陕西红马科技有限公司

Dates

Publication Date
20260512
Application Date
20230406

Claims (9)

  1. 1. The preparation method of the high-compaction lamellar metal lithium compound is characterized in that the high-compaction lamellar metal lithium compound comprises a lamellar metal lithium compound F1 and a lamellar metal lithium compound F2, wherein the molecular formula of the high-compaction lamellar metal lithium compound is F1 x F2 y , x+y=1, the expression general formula of the lamellar metal lithium compound F1 and the lamellar metal lithium compound F2 is Li (Ni 2+ m1 Ni 3+ n1 ) a M b N c O 2 , wherein m1+n1=1, and the quantity ratio of Ni 2+ in the lamellar metal lithium compound F1 and the lamellar metal lithium compound F2 in the total Ni satisfies the condition 1< m1 F1 /m1 F2 ≤2、0.04≤m1 F1 /n1 F1 is less than or equal to 2 and 0.02 is less than or equal to m1 F2 /n1 F2 is less than or equal to 1; The method comprises the following steps: Step 1, screening a precursor P1 and a precursor P2, wherein the granularity satisfies the conditions of 0.1-D10/D50-0.8, D100 P1 ≤D0 P2 and 1-D50 P2 *m1 F2 )/(D50 P1 *m1 F1 -4; Step 2, preprocessing the precursor P1 and the precursor P2 to prepare an intermediate M1 and an intermediate M2, wherein the specific surface area of the intermediate M1 and the intermediate M2 meets the conditions of 1M 2 /g≤SSA≤5m 2 /g and 0.8-0 SSA M1 /SSA M2 -0.2, characteristic peaks respectively appear near 2θ=18.6 °, 36.5 °, 38.0 °, 44.3 ° and 64.5 ° in an XRD spectrum, the characteristic peaks near 38.0 ° and 64.5 ° are single peaks, and the crystal face distances d corresponding to the 5 characteristic peaks are respectively And The ratio of the peak intensities I 1 /I 4 of the 1 st characteristic peak to the 4 th characteristic peak is 0.5-1.5, and the ratio of the peak intensities I 2 /I 3 of the 2 nd characteristic peak to the 3 rd characteristic peak is 0.5-1.5; And 3, mixing the intermediate M1, the intermediate M2 and the N-containing compound, doping, sintering and crushing to obtain the high-compaction lamellar lithium metal compound with bimodal particle size distribution.
  2. 2. The method of claim 1, wherein the M element and the N element are at least one of Co, mn, B, F, mg, S, K, na, al, ti, cr, ga, zr, nb, mo, ru, sn, W elements, wherein the M element contains at least one element having a valence > 3.
  3. 3. The method for producing a highly compacted layered lithium metal compound according to claim 1, wherein 0.6< a≤1, 0<b≤0.4, 0≤c≤0.05, and a+b=1.
  4. 4. The method for preparing a highly compacted layered lithium metal compound according to claim 1, wherein in the step 1, the precursor P1 and the precursor P2 are prepared by preparing a Ni salt and an M compound into a mixed salt solution, respectively, and performing a coprecipitation reaction, wherein the Ni salt is at least one of nickel sulfate, nickel chloride, nickel nitrate, nickel oxalate, and nickel acetate, and the M compound is at least one of sulfate, nitrate, oxalate, and sodium M-sulfonate containing M element.
  5. 5. The method for preparing a highly compacted layered lithium metal compound according to claim 1, wherein in the step 2, the pretreatment method is as follows: mixing the precursor P1 and the precursor P2 with lithium salt respectively, and performing negative pressure sintering in an atmosphere with the oxygen concentration of more than 20%; Or mixing the precursor P1, the precursor P2 and the lithium salt, and performing negative pressure sintering in an atmosphere with the oxygen concentration of more than 20%.
  6. 6. The method for producing a highly compacted layered lithium metal compound according to claim 5, wherein in the step 2, the lithium hydroxide content of the intermediate M1 and the intermediate M2 is 5000 to 100000ppm.
  7. 7. The method for preparing a highly compacted layered lithium metal compound according to claim 5, wherein in the step 2, the molar ratio of the precursor P1 to the precursor P2 to the lithium salt is 1.02 to 1.10, and the particle size of the lithium salt is 100 to 2000 μm.
  8. 8. The method for producing a highly compacted layered lithium metal compound according to claim 5, wherein in the step 2, the negative pressure is (-1) Pa- (-20) Pa, the sintering temperature is 300-700 ℃, and the sintering time is 2-8 hours.
  9. 9. The method for producing a highly compacted layered lithium metal compound according to claim 1, wherein in the step 3, the sintering temperature is 600 to 1000 ℃ and the sintering time is 6 to 30 hours.

Description

Preparation method of high-compaction layered metal lithium compound Technical Field The invention relates to the technical field of lithium ion secondary battery materials, in particular to a preparation method of a high-compaction layered metal lithium compound. Background From the application field of lithium batteries in China, the rapid development of industries such as power, energy storage and 3C has become a main driving force for the development of lithium ion battery industries, and the demands of the power and energy storage fields on lithium batteries are continuously accelerated. As the requirements of the pure electric vehicles on the endurance mileage are continuously improved, the requirements of power battery production enterprises on improving the energy density of the lithium batteries are increased. Increasing the relative content of nickel in the material, increasing the compacted density of the material is critical to increasing the energy density of the battery. However, the higher the nickel content, the poorer the cycle stability and the single-component material does not have the advantage of high compaction, and the pursuing of an increase in nickel content is not the preferred option for high energy density battery materials. As one solution to the above problem, a technique of using, as a positive electrode material, a high nickel base material gradation of two or more different median particle diameters D50 has been proposed. The method is realized by mixing finished products or mixing and sintering precursors, wherein the high-nickel base materials with different median particle diameters D50 are required to be prepared respectively, the preparation method is complex and high in cost, and the method is simplified, but the sintering system cannot well consider different high-nickel base materials, the uniformity of the prepared materials is poor, and the performance is limited. The present inventors have found, through continuous experimental studies, that the optimal sintering schedule of two high nickel substrates can be satisfied at the same time only when the ratio of the product of D50 and the number ratio of Ni 2+ in total Ni of the two high nickel substrates satisfies a certain condition, and that the material uniformity and further the productivity can be improved by controlling the specific surface area, structural characteristics and lithium hydroxide content of the intermediate, thereby obtaining a highly compacted metallic lithium compound having more excellent properties, and completed the present invention. Disclosure of Invention In view of the above, the present invention provides a preparation method of a highly compacted layered lithium metal compound, which is simple and low in cost, and the prepared highly compacted layered lithium metal compound has good uniformity and excellent performance. In order to achieve the above purpose, the invention provides a preparation method of a high-compaction lamellar metallic lithium compound, which adopts the following technical scheme: The preparation method of the high-pressure solid layered metal lithium compound comprises a layered metal lithium compound F1 and a layered metal lithium compound F2, wherein the molecular formula of the high-pressure solid layered metal lithium compound is F1 xF2y, x+y=1, the expression general formula of the layered metal lithium compound F1 and the layered metal lithium compound F2 is Li (Ni 2+m1Ni3+n1)aMbNcO2, wherein m1+n1=1, and the quantity ratio of Ni 2+ in the layered metal lithium compound F1 and the layered metal lithium compound F2 in total Ni satisfies the conditions 1< m1 F1/m1F2≤2、0.04≤m1F1/n1F1 is less than or equal to 2 and 0.02 is less than or equal to m1 F2/n1F2 is less than or equal to 1; The method comprises the following steps: Step 1, screening a precursor P1 and a precursor P2, wherein the granularity satisfies the conditions of 0.1-D10/D50-0.8, D100 P1≤D0P2 and 1-D50 P2*m1F2)/(D50P1*m1F1 -4; Step 2, preprocessing the precursor P1 and the precursor P2 to prepare an intermediate M1 and an intermediate M2, wherein the specific surface area of the intermediate M1 and the intermediate M2 meets the conditions of 1M 2/g≤SSA≤5m2/g and 0.8-0 SSA M1/SSAM2 -0.2, characteristic peaks respectively appear near 2θ=18.6 °, 36.5 °, 38.0 °, 44.3 ° and 64.5 ° in an XRD spectrum, the characteristic peaks near 38.0 ° and 64.5 ° are single peaks, and the crystal face distances d corresponding to the 5 characteristic peaks are respectively AndThe ratio of the peak intensities I 1/I4 of the 1 st characteristic peak to the 4 th characteristic peak is 0.5-1.5, and the ratio of the peak intensities I 2/I3 of the 2 nd characteristic peak to the 3 rd characteristic peak is 0.5-1.5; And 3, mixing the intermediate M1, the intermediate M2 and the N-containing compound, doping, sintering and crushing to obtain the high-compaction lamellar lithium metal compound with bimodal particle size distrib