CN114335508A - Single-crystal ternary cathode material, preparation method thereof and lithium ion battery - Google Patents
Single-crystal ternary cathode material, preparation method thereof and lithium ion battery Download PDFInfo
- Publication number
- CN114335508A CN114335508A CN202111627186.XA CN202111627186A CN114335508A CN 114335508 A CN114335508 A CN 114335508A CN 202111627186 A CN202111627186 A CN 202111627186A CN 114335508 A CN114335508 A CN 114335508A
- Authority
- CN
- China
- Prior art keywords
- single crystal
- cathode material
- ternary cathode
- precursor
- crystal ternary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 158
- 239000010406 cathode material Substances 0.000 title claims abstract description 92
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 20
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 12
- 239000002243 precursor Substances 0.000 claims abstract description 76
- 238000005245 sintering Methods 0.000 claims abstract description 67
- 239000000654 additive Substances 0.000 claims abstract description 29
- 230000000996 additive effect Effects 0.000 claims abstract description 28
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 22
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 11
- 229910052796 boron Inorganic materials 0.000 claims abstract description 10
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 10
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 10
- 229910052712 strontium Inorganic materials 0.000 claims abstract description 10
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 10
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 9
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 9
- 229910052727 yttrium Inorganic materials 0.000 claims abstract description 9
- 239000007774 positive electrode material Substances 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 8
- 229910013467 LiNixCoyMnzO2 Inorganic materials 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000002245 particle Substances 0.000 abstract description 49
- 239000000463 material Substances 0.000 abstract description 43
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 abstract description 21
- 230000008901 benefit Effects 0.000 abstract description 12
- 150000003839 salts Chemical class 0.000 abstract description 11
- 229910052759 nickel Inorganic materials 0.000 abstract description 10
- 150000004679 hydroxides Chemical class 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 230000007547 defect Effects 0.000 abstract description 2
- 230000002708 enhancing effect Effects 0.000 abstract 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 33
- 230000000052 comparative effect Effects 0.000 description 30
- 239000000243 solution Substances 0.000 description 30
- 238000006243 chemical reaction Methods 0.000 description 23
- 229910000018 strontium carbonate Inorganic materials 0.000 description 19
- 239000003513 alkali Substances 0.000 description 15
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 14
- 235000011114 ammonium hydroxide Nutrition 0.000 description 14
- 239000011259 mixed solution Substances 0.000 description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 10
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 238000005406 washing Methods 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 238000010924 continuous production Methods 0.000 description 8
- BDAGIHXWWSANSR-NJFSPNSNSA-N hydroxyformaldehyde Chemical compound O[14CH]=O BDAGIHXWWSANSR-NJFSPNSNSA-N 0.000 description 8
- 238000001878 scanning electron micrograph Methods 0.000 description 8
- 238000007873 sieving Methods 0.000 description 8
- 239000010405 anode material Substances 0.000 description 7
- 239000003792 electrolyte Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- LEDMRZGFZIAGGB-UHFFFAOYSA-L strontium carbonate Chemical compound [Sr+2].[O-]C([O-])=O LEDMRZGFZIAGGB-UHFFFAOYSA-L 0.000 description 7
- 238000009826 distribution Methods 0.000 description 6
- 239000011572 manganese Substances 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- 239000007795 chemical reaction product Substances 0.000 description 4
- 229910017052 cobalt Inorganic materials 0.000 description 4
- 239000010941 cobalt Substances 0.000 description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000007086 side reaction Methods 0.000 description 4
- 238000011282 treatment Methods 0.000 description 4
- 239000002585 base Substances 0.000 description 3
- 229940044175 cobalt sulfate Drugs 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 230000001351 cycling effect Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000010902 jet-milling Methods 0.000 description 3
- 150000002696 manganese Chemical class 0.000 description 3
- 229940099596 manganese sulfate Drugs 0.000 description 3
- 239000011702 manganese sulphate Substances 0.000 description 3
- 235000007079 manganese sulphate Nutrition 0.000 description 3
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 229940073644 nickel Drugs 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000010923 batch production Methods 0.000 description 2
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 229910052923 celestite Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 150000001868 cobalt Chemical class 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000001095 magnesium carbonate Substances 0.000 description 2
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 2
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 2
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 2
- 239000000347 magnesium hydroxide Substances 0.000 description 2
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 2
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Inorganic materials [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 150000002815 nickel Chemical class 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000004537 pulping Methods 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910001631 strontium chloride Inorganic materials 0.000 description 2
- AHBGXTDRMVNFER-UHFFFAOYSA-L strontium dichloride Chemical compound [Cl-].[Cl-].[Sr+2] AHBGXTDRMVNFER-UHFFFAOYSA-L 0.000 description 2
- UUCCCPNEFXQJEL-UHFFFAOYSA-L strontium dihydroxide Chemical compound [OH-].[OH-].[Sr+2] UUCCCPNEFXQJEL-UHFFFAOYSA-L 0.000 description 2
- 229910001866 strontium hydroxide Inorganic materials 0.000 description 2
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910012888 LiNi0.6Co0.1Mn0.3O2 Inorganic materials 0.000 description 1
- 229910011328 LiNi0.6Co0.2Mn0.2O2 Inorganic materials 0.000 description 1
- 229910011624 LiNi0.7Co0.1Mn0.2O2 Inorganic materials 0.000 description 1
- 229910001290 LiPF6 Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Inorganic materials [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000002572 peristaltic effect Effects 0.000 description 1
- 238000011085 pressure filtration Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011163 secondary particle Substances 0.000 description 1
- 238000007581 slurry coating method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a single crystal ternary cathode material, a preparation method thereof and a lithium ion battery. Specifically, the single-crystal ternary cathode material is mainly obtained by sintering a precursor of the ternary cathode material, a lithium source and an additive; the crystallinity of the precursor is 60-70%, and the crystallinity of the single crystal ternary cathode material is 80-90%; the additive comprises one or more of oxides, hydroxides and salts of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B. The invention makes up the defects of the preparation cost and the material performance of the single crystal material compared with the polycrystalline material in the prior art, the prepared single crystal ternary cathode material has the advantages of high specific capacity, good rate capability, strong cycle performance and the like, and meanwhile, the single crystal particles have uniform size, thereby not only reducing the mixed arrangement of lithium and nickel, but also enhancing the stability of a laminated structure and being beneficial to the exertion of the battery capacity.
Description
Technical Field
The invention relates to the field of ternary materials, in particular to a single crystal ternary cathode material, a preparation method thereof and a lithium ion battery.
Background
With the continuous development of new energy industry, lithium ion batteries are widely and deeply researched. The quality of the anode material is the key point for determining the performance of the lithium ion battery, and the nickel-cobalt-manganese ternary anode material is an ideal battery material for the electric automobile due to higher theoretical energy density and longer cycle life.
Compared with a ternary cathode material with a polycrystalline structure, the ternary cathode material with the single crystal structure has the following advantages: firstly, the specific surface is low, the structural stability is high, and the cycle stability is good; for a polycrystalline structure, as the number of cycles increases, due to different crystal plane orientations and slip planes of primary particles in secondary spheres, anisotropy exists in the expansion and contraction of crystal lattices between crystal grains, so that secondary particle breakage may occur at the later stage of the cycle, and microcracks are generated between the primary particles. This increases the contact area between the material and the electrolyte, which in turn aggravates the side reaction between the material and the electrolyte, resulting in a decrease in cycle performance. Under the combined action of low specific surface area and excellent structural stability, the single crystal structure can still keep the original shape and structure after long circulation, and the circulation stability is good. Good cycling stability is critical to the safety of the battery. Secondly, the operating voltage is high and the thermal stability is good. The single crystal material can be kept stable under high voltage, can effectively resist oxidative electrolyte, can relieve the problems of gas generation, long cycle, thermal stability and the like, and is an effective way for improving the energy density of the material. Thirdly, the compaction density is high and the volumetric energy density is high.
However, monocrystalline materials still have a number of disadvantages compared to conventional polycrystalline materials: because the single particles of the single crystal material are large, Li+Since diffusion is more difficult, when charging and discharging in the same voltage range, the specific discharge capacity of a single crystal material is generally low, and the capacity performance is inferior to that of a polycrystalline material, and the rate capability is poor. Meanwhile, compared with polycrystalline materials, the preparation process of single crystal materials generally needs higher sintering temperature, has poorer particle uniformity and high crushing processing requirement, and increases the production cost.
Therefore, in order to meet the requirements of power batteries, consumer electronics and the like on the positive electrode materials of lithium ion batteries, the preparation of single crystal materials with better performance and higher application value is urgently needed.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The invention aims to provide a single crystal ternary cathode material which is prepared from a precursor material with low crystallinity, and the material can reduce the sintering temperature required by the single crystal ternary cathode material and avoid the problem of overlarge Li loss caused by high-temperature sintering due to the low crystallinity of the precursor material.
The second purpose of the invention is to provide a preparation method of the single crystal ternary cathode material, wherein a precursor of the single crystal ternary cathode material adopts a continuous production process, so that the production cost is greatly reduced, and the productivity is improved; meanwhile, the precursor is matched with a lithium source and an additive, so that the uniformity of the size of single crystal particles is improved, the mixed arrangement of lithium and nickel can be reduced, the stability of a laminated structure is enhanced, and the capacity can be exerted.
The third purpose of the invention is to provide a lithium ion battery, which comprises the single crystal ternary cathode material, wherein the single crystal ternary cathode material has higher crystallinity, and can improve the first discharge specific capacity and the first efficiency of the battery; in addition, the material has a lower specific surface area, can effectively reduce the side reaction between the surface of the material and electrolyte, and can reduce the content of residual alkali at the same time, thereby achieving the effect of improving the cycling stability of the battery.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
the single crystal ternary cathode material is mainly obtained by sintering a precursor of the ternary cathode material, a lithium source and an additive;
wherein the single crystal ternary positive electrode material is LiNixCoyMnzO2X + y + z is 1, x is more than 0 and less than 1, y is more than 0 and less than 1, and z is more than 0 and less than 1; preferably, x is more than or equal to 0.5 and less than 0.9, y is more than 0.1 and less than 0.4, and z is more than 0.1 and less than 0.4;
the crystallinity of the precursor is 60-70%, and the crystallinity of the single crystal ternary cathode material is 80-90%;
the additive comprises compounds of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B.
The single crystal ternary cathode material provided by the invention adopts a precursor material with low crystallinity, so that the required sintering temperature can be reduced, and the problem of excessive Li loss caused by high-temperature sintering is avoided. The addition of the additive can promote the fusion and growth of the particles and enhance the uniformity of the particles. The obtained single crystal ternary cathode material has more uniform granularity, and has the advantages of small specific surface area, low residual alkali, high stability and the like, and also has the advantages of high specific capacity, good rate capability, strong cycle performance and the like.
Preferably, the Span of the precursor is 1-1.5.
Preferably, D of the precursor50The value is 3.0 to 4.5. mu.m.
Preferably, the Span of the single crystal ternary cathode material is 0.7-1.4.
Preferably, theD of the single crystal ternary cathode material503.0 to 4.5 μm.
Preferably, the single crystal ternary cathode material has a BET of 0.3m2/g～0.6m2/g。
Preferably, the Span ratio of the single crystal ternary cathode material to the precursor is 0.7-0.9.
Preferably, the additive accounts for 0.05-0.6% of the mass of the precursor.
The invention provides a preparation method of a single crystal ternary cathode material, which comprises the following steps:
mixing a precursor of the single crystal ternary cathode material with the crystallinity of 60-70%, a lithium source and an additive, and then sintering in an oxygen-containing atmosphere to obtain the single crystal ternary cathode material with the crystallinity of 80-90%;
wherein the single crystal ternary positive electrode material is LiNixCoyMnzO2X + y + z is 1, x is more than 0 and less than 1, y is more than 0 and less than 1, and z is more than 0 and less than 1; preferably, x is more than or equal to 0.5 and less than 0.9, y is more than 0.1 and less than 0.4, and z is more than 0.1 and less than 0.4;
the additive comprises compounds of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B.
Preferably, the additive accounts for 0.05-0.6% of the mass of the precursor.
Preferably, the sintering comprises:
heating to 400-650 ℃ at the heating rate of 2-10 ℃/min for the first sintering, and then heating to 700-1000 ℃ at the heating rate of 2-10 ℃/min for the second sintering.
Preferably, the time for the first sintering is 2-6 h.
Preferably, the time of the second sintering is 10-15 h.
The lithium ion battery provided by the invention comprises the single crystal ternary cathode material or the single crystal ternary cathode material prepared by the preparation method of the single crystal ternary cathode material.
Compared with the prior art, the invention has the beneficial effects that:
(1) the nickel-cobalt-manganese ternary single crystal anode material has small specific surface area and low residual alkali of 600ppm, so that the surface stability of single crystal particles is better, the occurrence of surface side reaction with electrolyte is reduced, and the stability of the anode material is improved.
(2) The precursor of the single crystal ternary cathode material adopts a continuous production process with wide particle size distribution in the preparation process, and although the particle size of the precursor is quite uneven and the crystallinity is low, the doping component is added in the later preparation process, so that the uniformity of the particle size of the single crystal is improved, the mixed arrangement of lithium and nickel is reduced, the stability of a layered structure is enhanced, and the capacity development quality is facilitated.
(3) The precursor of the nickel-cobalt-manganese ternary single crystal positive electrode material has low crystallinity, so that the sintering temperature required for forming a good single crystal appearance is low, and the problems of high sintering temperature and high energy consumption of more crystals in single crystal sintering are relieved to a certain extent. Meanwhile, a continuous precursor process is combined with a sintering process, so that the production cost is reduced and the productivity is improved on the basis of obtaining excellent single crystal materials.
(4) Compared with single crystal materials in the same proportion, the nickel-cobalt-manganese ternary single crystal positive electrode material has more excellent specific capacity, rate capability and cycle performance. The single crystal material of the present invention has a small particle diameter, Li+Has shorter migration distance, better solves the problems of larger single crystal particles and Li+Difficult diffusion, low specific discharge capacity and poor rate capability.
(5) According to the preparation method of the single crystal ternary cathode material, the precursor of the single crystal ternary cathode material adopts a continuous production process, so that the production cost is greatly reduced, and the productivity is improved; meanwhile, the precursor is matched with a lithium source and an additive, so that the uniformity of the size of single crystal particles is improved, the mixed arrangement of lithium and nickel can be reduced, the stability of a laminated structure is enhanced, and the capacity can be exerted.
(6) According to the preparation method of the single crystal ternary cathode material, provided by the invention, the additive is added, the particle size distribution is narrowed while the capacity is not reduced, the particle uniformity is improved, the problems of scratches, band breakage and the like during slurry coating forming are prevented, the surface smoothness of the material is improved, and the quality of the prepared single crystal ternary cathode material is improved.
(7) According to the lithium ion battery provided by the invention, the single-crystal ternary cathode material is adopted to prepare the cathode pole piece, so that the stability and consistency of battery manufacturing are enhanced, and the cycling stability of the material is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is an SEM image of the precursor (a) and the single-crystal cathode material (b) provided in example 1 of the present invention;
fig. 2 is an SEM image of the precursor (a) and the single-crystal cathode material (b) provided in example 2 of the present invention;
FIG. 3 is an SEM image of the precursor (a) and the single-crystal cathode material (b) provided in example 3 of the present invention;
FIG. 4 is an SEM image of the precursor (a) and the single-crystal cathode material (b) provided in comparative example 1 of the present invention;
FIG. 5 is an SEM image of the precursor (a) and the single-crystal cathode material (b) provided in comparative example 2 of the present invention;
FIG. 6 is an SEM image of the precursor (a) and the single-crystal cathode material (b) provided in comparative example 3 of the present invention;
FIG. 7 is an SEM image of the precursor (a) and the single-crystal cathode material (b) provided in comparative example 4 of the present invention;
FIG. 8 is a comparative XRD diagram of the precursors provided in examples 1-3 and comparative example 1 of the present invention;
fig. 9 is a graph showing cycle performance of a lithium battery according to an experimental example of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The single crystal ternary cathode material is specially provided aiming at various technical defects of low specific discharge capacity, more poor crystal materials for capacity exertion, poor rate performance, high sintering temperature required by preparation, poor particle uniformity, high crushing processing requirement, high production cost and the like of single crystal materials in the prior art. The invention is realized by the following technical scheme:
in a preferred embodiment of the invention, the single crystal ternary cathode material is mainly obtained by sintering a precursor of the ternary cathode material, a lithium source and an additive;
wherein the single crystal ternary positive electrode material is LiNixCoyMnzO2X + y + z is 1, 0 < x < 1 (e.g., x may be 0.2, 0.5, 0.7, 0.9), 0 < y < 1 (e.g., y may be 0.1, 0.2, 0.5, 0.7, 0.9), 0 < z < 1 (e.g., z may be 0.1, 0.2, 0.5, 0.7, 0.9); the crystallinity of the precursor is 60-70%, and the precursor with low crystallinity is used as a raw material to obtain the single crystal ternary cathode material with the crystallinity of 80-90%, so that the sintering temperature required by the single crystal ternary cathode material can be reduced, and the problem of excessive Li loss caused by high-temperature sintering is avoided. The single crystal ternary cathode material has the advantages of small specific surface area, low residual alkali, high stability and the like, and also has the advantages of high specific capacity, good rate capability, strong cycle performance and the like.
Wherein the crystallinity of the precursor is 60-70%, and the crystallinity of the precursor includes but is not limited to: 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%; the XRD integral width of the precursor is 0.5-0.8, including but not limited to 0.5, 0.6, 0.7 and 0.8; the crystallinity of the single crystal ternary cathode material is 80-90%, including but not limited to 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%.
Preferably, the precursor is a precursor material produced in a continuous production mode, the Span of the continuous production process is high, particles with small particle size exist, and the precursor is easy to over-fire in the sintering process, so that the quality of the anode is influenced. The preparation method has the advantages that the characteristic of low crystallinity is utilized, the single crystal sintering temperature is reduced, the sintering and raw material cost can be reduced, the residual Li content can be reduced, the high-crystallinity cathode material is obtained, the uniformity of particles is improved, scratches and broken strips are prevented from occurring during pulping coating forming, the surface smoothness of the material is improved, the stability and consistency of battery manufacturing are enhanced, and the circulation stability of the material is improved. But also can reduce the content of residual alkali and achieve the effect of improving the circulation stability.
The crystallinity testing method adopted by the invention comprises the following steps: the X-ray diffraction test is carried out by adopting a German Bruker instrument, the total integral area and the amorphous scattering peak area can be automatically calculated by DIFFAC. EVA V4.2.2 software, and the crystallinity value is read.
From the crystallinity and XRD integrated width: the precursor of the single crystal ternary cathode material has lower crystallinity, so that the single crystal sintering temperature is reduced. When the sintering temperature is higher, the loss of Li is too large, and the excessive Li is required to be increased to compensate the loss of Li during sintering, which inevitably causes the increase of the content of residual Li, thereby causing the reduction of the material capacity and the cycle performance. By lowering the single crystal sintering temperature: firstly, the cost of sintering and raw materials is reduced, and secondly, the content of residual Li is reduced, thereby realizing the improvement of the capacity and the cycle stability of the single crystal material.
In a preferred embodiment, 0.5. ltoreq. x < 0.9, 0.1 < y < 0.4, 0.1 < z < 0.4.
Wherein, the values of x, y and z are any real numbers in the corresponding ranges, the value of x includes but is not limited to 0.5, 0.6, 0.7 and 0.8, the value of y includes but is not limited to 0.2 and 0.3, and the value of z includes but is not limited to 0.2 and 0.3.
Wherein the additive comprises compounds of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B, the compounds comprise one or more of oxides, hydroxides and salts of Sr, Ca, Mg, Al, Zr and B, such as SrO and SrO2、Sr(OH)2、SrCO3、SrCO3、SrNO3、SrCl2、SrSO4、SrS、CaCO3、MgCO3、Mg(OH)2、Mg(NO3)2、ZrO、ZrCO3、B2O3And H3BO3。
As a more preferred embodiment, the additive comprises the oxide of Sr, the salt of Sr and H3BO3The combination of (1); such as SrO, SrCO3Combinations of (A) with (B), e.g. SrO2And SrNO3Combinations of (a), (b), (c), (d); wherein, the above mentioned preferred components can also be combined with each other to form a new technical scheme.
As a further preferred embodiment, SrCO is selected as the additive3。
The single crystal ternary cathode material provided by the invention adopts a precursor material with low crystallinity, so that the required sintering temperature can be reduced, and the problem of excessive Li loss caused by high-temperature sintering is avoided. The addition of the additive can promote the fusion and growth of the particles and enhance the uniformity of the particles. The obtained single crystal ternary cathode material has more uniform granularity, and has the advantages of small specific surface area, low residual alkali, high stability and the like, and also has the advantages of high specific capacity, good rate capability, strong cycle performance and the like.
In a preferred embodiment, the Span of the precursor is 1 to 1.5, preferably 1.0 to 1.3, and the Span of the single crystal ternary cathode material is 0.7 to 1.4.
Continuous wide distribution Span (Span ═ D)90-D10)/D50) Is one describing the width of the particle size distributionA larger Span indicates a larger difference in particle size. The Span of the single crystal ternary cathode material is narrowed, which shows that the distribution range of the particles of the cathode material is narrowed compared with that of a precursor, and the uniformity is improved.
In a preferred embodiment, the ratio of the single crystal ternary cathode material to the Span of the precursor is 0.7-0.9.
As a preferred embodiment, D of said precursor50Values of 3.0 μm to 4.5 μm, including but not limited to: 3.0 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4.0 μm, 4.1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm; d of the single-crystal ternary cathode material503.0 μm to 4.5 μm, including but not limited to 3.0 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4.0 μm, 4.1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm.
D50The median particle diameter is the corresponding particle diameter when the cumulative particle size distribution percentage reaches 50 percent; when the precursor has a suitable D50When the value is higher, the anode material can be ensured to have proper D50Value to shorten Li+Increase in migration distance and increase in Li+The advantage of the transmission capability, thereby improving the electrochemical performance of the anode material.
In general, single crystals are large in size, Li+Diffusion is difficult and therefore has a lower capacity than polycrystalline materials. The single crystal ternary anode material of the invention contains more suitable D50Can reduce Li+Diffusion distance, in favor of Li+The material can be effectively improved in rate capability.
As a preferred embodiment, the single crystal ternary positive electrode material has a BET of 0.3m2/g～0.6m2Per g, including but not limited to 0.3m2/g、0.35m2/g、0.4m2/g、0.45m2/g、0.5m2/g、0.55m2/g、0.6m2/g。
The lower specific surface area can effectively reduce the side reaction between the material surface and the electrolyte, and simultaneously can reduce the content of residual alkali, thereby achieving the effect of improving the circulation stability.
As a preferred embodiment, the additive is 0.05% to 0.3% of the mass of the precursor, including but not limited to 0.05%, 0.06%, 0.09%, 0.1%, 0.11%, 0.13%, 0.15%, 0.18%, 0.2%, 0.21%, 0.23%, 0.25%, 0.28%, 0.3%.
The preparation method of the single crystal ternary cathode material provided by the other embodiment of the invention comprises the following steps:
mixing a precursor of the single crystal ternary cathode material with the crystallinity of 60-70%, a lithium source and an additive, and then sintering in an oxygen-containing atmosphere to obtain the single crystal ternary cathode material with the crystallinity of 80-90%;
wherein the single crystal ternary positive electrode material is LiNixCoyMnzO2X + y + z is 1, x is more than 0 and less than 1, y is more than 0 and less than 1, and z is more than 0 and less than 1; preferably, x is more than or equal to 0.5 and less than 0.9, y is more than 0.1 and less than 0.4, and z is more than 0.1 and less than 0.4;
the additive comprises compounds of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B, the compounds comprise one or more of oxides, hydroxides and salts of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B, such as SrO and SrO2、Sr(OH)2、SrCO3、SrCO3、SrNO3、SrCl2、SrSO4、SrS、CaCO3、MgCO3、Mg(OH)2、Mg(NO3)2、ZrO、ZrCO3、B2O3And H3BO3. Sr, Ca, Mg, Al, Zr, Y, Nb, W and B can be used for homogenizing the particle size of the cathode material and improving the crystallinity of the cathode material.
The single crystal ternary cathode material provided by the invention adopts a precursor material with low crystallinity, so that the required sintering temperature can be reduced, and the problem of excessive Li loss caused by high-temperature sintering is avoided. The addition of the additive can promote the fusion and growth of the particles and enhance the uniformity of the particles. The obtained single crystal ternary cathode material has more uniform granularity, has the advantages of small specific surface area, low residual alkali, high stability and the like, and also has the advantages of high specific capacity, good rate capability, strong cycle performance and the like.
As a preferred embodiment, the additive is 0.05% to 0.6% of the mass of the precursor, including but not limited to 0.05%, 0.06%, 0.09%, 0.1%, 0.11%, 0.13%, 0.15%, 0.18%, 0.2%, 0.21%, 0.23%, 0.25%, 0.28%, 0.3%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45%, 0.50%, 0.55%, 0.58%, 0.6%.
As a preferred embodiment, sintering is carried out at a lower single crystal sintering temperature, and the method specifically comprises the following steps:
heating to 400-650 ℃ at the heating rate of 2-10 ℃/min for the first sintering, and then heating to 700-1000 ℃ at the heating rate of 2-10 ℃/min for the second sintering.
Preferably, the time for the first sintering is 2-6 h.
Preferably, the time of the second sintering is 10-15 h.
As a preferred embodiment, the preparation method of the precursor of the single crystal ternary cathode material comprises the following steps: mixing the mixed solution of nickel salt, cobalt salt and manganese salt with sodium hydroxide and ammonia water, carrying out complex reaction, and dehydrating to a certain degree to obtain the precursor;
as a more preferred embodiment, the method for preparing the precursor of the single crystal ternary cathode material mainly comprises the following steps:
a) adding a certain amount of water into a reaction kettle, setting a protective gas environment, and simultaneously introducing a mixed solution of nickel salt, cobalt salt and manganese salt, a sodium hydroxide solution and an ammonia water solution into the reaction kettle at a constant speed through a peristaltic pump to perform a complex reaction;
b) washing a reaction product, dehydrating by mechanical force, and then dehydrating by thermal force to a certain degree to obtain the precursor;
as a further preferred embodiment, in step a), the shielding gas comprises nitrogen; further preferably, nitrogen is introduced into the reaction kettle while the water is in a stirring state;
as a further preferred embodiment, in step a), the nickel, cobalt and manganese salts respectively comprise at least one of nitrate, sulfate and chloride;
in a further preferred embodiment, in step a), the concentration of the mixed solution is 80g/L to 120 g/L;
as a further preferred embodiment, in step a), the concentration of the aqueous ammonia solution is from 0.1mol/L to 5 mol/L;
in a further preferred embodiment, in the step a), the pH of the reaction solution obtained by mixing the mixed solution, the sodium hydroxide solution and the ammonia water solution is 10 to 13;
as a further preferred embodiment, in step a), the uniform speed includes: the flow rate of the mixed solution is 3L/h-10L/h, the flow rate of the sodium hydroxide solution is 1L/h-5L/h, and the flow rate of the ammonia water solution is 0.1L/h-0.5L/h;
as a further preferred embodiment, in step a), the reaction conditions of the complexation reaction include: the reaction temperature is 50-70 ℃, the pH is 11.5-12.5, and the stirring speed is 500-1000 r/min;
as a further preferred embodiment, in step b), the washing comprises water washing and/or alkali washing;
as a further preferred embodiment, in step b), said mechanical dewatering comprises at least one of centrifugation, filtration, pressure filtration;
as a further preferred embodiment, in step b), the thermal dehydration further comprises sieving, demagnetizing and other treatments.
In a preferred embodiment, the molar ratio of Li in the lithium source to the total molar amount of Ni, Co and Mn in the precursor is (1-1.2): 1;
as a more preferred embodiment, the molar ratio of Li in the lithium source to the total molar amount of Ni, Co, Mn in the precursor includes, but is not limited to, 1: 1. 1.05: 1. 1.1: 1. 1.15: 1. 1.2: 1;
as a more preferred embodimentIn one embodiment, the lithium source comprises Li2CO3、LiOH、LiOH·H2O and LiNO3At least one of (1).
As a preferred embodiment, the sintered product further comprises: and (4) airflow crushing and sieving.
Meanwhile, the sintered powder material is easy to generate larger special-shaped particles due to adhesion and breakage, and scratches and broken strips are easy to generate during pulping, coating and molding.
The lithium ion battery provided by the invention comprises the single crystal ternary cathode material or the single crystal ternary cathode material prepared by the preparation method of the single crystal ternary cathode material.
Example 1
1) Mixing the components in a molar ratio of 0.6: 0.2: 0.2 of nickel, cobalt and manganese sulfate crystals are prepared into a uniform ternary metal salt mixed solution of 116g/L, pure water, a sodium hydroxide solution with the mass concentration of 32% and an ammonia water solution with the mass concentration of 21% are added into a reaction kettle to prepare a base solution with the pH value of 12.0, nitrogen is introduced to protect and prevent oxidation, a stirrer is started, the rotating speed is 500r/min, and the reaction kettle is heated to 60 ℃.
2) Simultaneously introducing the ternary metal salt mixed solution, a sodium hydroxide solution and an ammonia water solution into a reaction kettle, controlling the flow rate of the ternary metal salt solution to be 4L/h, the flow rate of the sodium hydroxide solution to be 2.0L/h, the flow rate of the ammonia water solution to be 0.3L/h, the reaction temperature to be 60 ℃, controlling the pH of a reaction system to be 11.9-12.0, continuously feeding and discharging by adopting a continuous process, and monitoring the granularity to D50It is stable at 3.5 μm.
3) Carrying out alkali washing, water washing, centrifuging, drying and sieving on the reaction product obtained in the step 2) to obtain a precursor Ni of the nickel-cobalt-manganese ternary single crystal positive electrode material0.6Co0.2Mn0.2(OH)2。
4) 2000g of the obtained precursor was mixed with LiOH. H2O is added according to a molar ratio of 1: a ratio of 1.05 to the total amount of the composition,with the addition of 1.8g of SrCO3And uniformly mixing by a high-speed mixer.
5) Sintering the mixture obtained in the step 4) in an air atmosphere by using a box furnace, wherein the sintering temperature is 890 ℃, the high-temperature sintering time is 10 hours, cooling to room temperature, and then carrying out jet milling and sieving treatment to obtain the nickel-cobalt-manganese ternary single crystal positive electrode material LiNi0.6Co0.2Mn0.2O2。
Example 2
1) Mixing the components in a molar ratio of 0.7: 0.1: 0.2 of nickel, cobalt and manganese sulfate crystals are prepared into a uniform ternary metal salt mixed solution of 116g/L, pure water, a sodium hydroxide solution with the mass concentration of 32% and an ammonia water solution with the mass concentration of 21% are added into a reaction kettle to prepare a base solution with the pH value of 12.0, nitrogen is introduced to protect and prevent oxidation, a stirrer is started, the rotating speed is 600r/min, and the reaction kettle is heated to 60 ℃.
2) Simultaneously adding the ternary metal salt mixed solution, ammonia water and liquid alkali into a reaction kettle, controlling the flow rate of the ternary metal salt to be 5L/h, the flow rate of the liquid alkali to be 2.0L/h, the flow rate of the ammonia water to be 0.2L/h, controlling the reaction temperature to be 60 ℃, controlling the pH range of a reaction system to be 11.9-12.0, adopting a continuous process, continuously feeding and discharging materials, and monitoring the granularity to D50It is stable at 3.5 μm.
3) Carrying out alkali washing, water washing, centrifuging, drying and sieving on the reaction product obtained in the step 2) to obtain a precursor Ni of the nickel-cobalt-manganese ternary single crystal positive electrode material0.7Co0.1Mn0.2(OH)2。
4) 2000g of the obtained precursor was mixed with LiOH. H2O is added according to a molar ratio of 1: 1.01, while adding 1.8g of SrCO3And uniformly mixing by a high-speed mixer.
5) Sintering the mixture obtained in the step 4) in an air atmosphere by using a box furnace, wherein the sintering temperature is 855 ℃, the high-temperature sintering time is 10 hours, cooling to room temperature, and then performing jet milling and sieving treatment to obtain the nickel-cobalt-manganese ternary single crystal positive electrode material LiNi0.7Co0.1Mn0.2O2。
Example 3
1) Mixing the components in a molar ratio of 0.6: 0.1: 0.3 of nickel, cobalt and manganese sulfate crystals are prepared into a uniform ternary metal salt mixed solution of 116g/L, pure water, a sodium hydroxide solution with the mass concentration of 32% and an ammonia water solution with the mass concentration of 21% are added into a reaction kettle to prepare a base solution with the pH value of 12.0, nitrogen is introduced to protect and prevent oxidation, a stirrer is started, the rotating speed is 700r/min, and the reaction kettle is heated to 60 ℃.
2) Simultaneously introducing the ternary metal salt mixed solution, a sodium hydroxide solution and an ammonia water solution into a reaction kettle, controlling the flow rate of the ternary metal salt solution to be 4L/h, the flow rate of the sodium hydroxide solution to be 2.0L/h, the flow rate of the ammonia water solution to be 0.2L/h, the reaction temperature to be 60 ℃, controlling the pH of a reaction system to be 11.9-12.0, continuously feeding and discharging by adopting a continuous process, and monitoring the granularity to D50It is stable at 3.5 μm.
3) Carrying out alkali washing, water washing, centrifuging, drying and sieving on the reaction product obtained in the step 2) to obtain a precursor Ni of the nickel-cobalt-manganese ternary single crystal positive electrode material0.6Co0.1Mn0.3(OH)2。
4) 2000g of the obtained precursor was mixed with LiOH. H2O is added according to a molar ratio of 1: 1.03, while adding 1.8g of SrCO3And uniformly mixing by a high-speed mixer.
5) Sintering the mixture obtained in the step 4) in an air atmosphere by using a box furnace, wherein the sintering temperature is 920 ℃, the high-temperature sintering time is 10 hours, cooling to room temperature, and then carrying out jet milling and sieving treatment to obtain the nickel-cobalt-manganese ternary single crystal positive electrode material LiNi0.6Co0.1Mn0.3O2。
Example 4
Example 4 is essentially the same as example 1, except that: in step (4), 1gMgCO is used3Replacement of 1.8g of SrCO3。
Example 5
Example 5 is essentially the same as example 1, except that: in the step (4), 6g of ZrO was used2Replacement of 1.8g of SrCO3。
Example 6
Example 6 and example 1The method is the same with the following differences: in step (4), 2gB is used2O3Replacement of 1.8g of SrCO3。
Comparative example 1
Essentially the same as example 1, except that:
a batch process is used in step 2).
Comparative example 2
Essentially the same as example 1, except that:
in step 2) a batch process was used and in step 5) the sintering temperature was 915 ℃.
Comparative example 3
Essentially the same as example 1, except that:
in step 4), SrCO is not added3。
Comparative example 4
Essentially the same as example 1, except that:
in step 4), SrCO is not added3The sintering temperature in step 5) was 915 ℃.
Comparative example 5
Essentially the same as example 1, except that:
the sintering temperature in step 5) was 915 ℃.
Experimental example 1 physicochemical Property index test
The physical and chemical performance indexes of the positive electrode materials provided in examples 1 to 6 and comparative examples 1 to 3 were tested and calculated, and the results are shown in table 1.
TABLE 1 calculation results of physicochemical Properties of examples and comparative examples
In addition, fig. 1 to 7 show SEM images of the precursor and the single crystal positive electrode material prepared in examples 1 to 3 and comparative examples 1 to 4, respectively. FIG. 8 shows a comparison of XRD patterns of the precursors of examples 1-3 and comparative example 1. The following conclusions can be drawn from FIGS. 1 to 8 and Table 1:
compared with the comparative example 1, the precursor of the comparative example 1 is intermittent, the particle size is uniform, the crystallinity is higher, the single crystal morphology particles formed by simultaneously adding 500pp strontium carbonate under 890 ℃ are smaller, the single crystal morphology is poorer, and the continuous increase of the single crystal sintering temperature is needed to obtain better single crystal morphology. Compared with the comparative example 2, the precursor of the comparative example 2 is in a batch type, has uniform particle size and higher crystallinity, and can form a single crystal morphology similar to that of the example 1 at 915 ℃. Thus, it can be seen that: the batch precursor requires a higher single crystal sintering temperature due to higher crystallinity, whereas the precursor in example 1 has lower crystallinity and lower single crystal temperature. The lower single crystal temperature can save the production cost and prevent Li caused by high-temperature sintering+And (4) volatilizing to improve the capacity of the material.
Example 1 in comparison to comparative example 3, comparative example 3 had no strontium carbonate added and both were sintered at the same single crystal temperature of 890 c. The appearance of the single crystal is seen from SEM, the phenomenon that the growth of the particles with different sizes is uneven obviously exists in the comparative example 3, most of the small particles cannot grow fully, and the size difference of the single crystal particles is obvious. After a small amount of strontium carbonate is doped, the single crystal particles grow uniformly and tend to be consistent in size. Example 1 in comparison with comparative example 4, comparative example 4 had no strontium carbonate added and the single crystal temperature increased to 915 ℃. It can be seen from comparative example 3 that, under the same single crystal temperature sintering conditions of undoped strontium carbonate, there is a phenomenon in which a large portion of small particles are not sufficiently grown without adding strontium carbonate, and thus comparative example 4 increases the single crystal sintering temperature to 915 ℃. From SEM, although the temperature of the single crystal is increased, the phenomenon of uneven growth of large and small particles is more serious, and the small particles still grow insufficiently while the large particles are over-sintered. Thus, it is demonstrated that the particle size non-uniformity phenomenon cannot be solved only by increasing the sintering temperature.
Example comparative example 5 the single crystal temperature was increased to 915 degrees celsius while adding strontium carbonate, compared to comparative example 5. From the SEM, the uniformity of single crystal grain growth was significantly improved with the addition of strontium carbonate, as demonstrated in comparative example 1. However, after the sintering temperature is increased to 915 ℃, single crystal particles are over-sintered, and fruits are crushed after crushing, so that a large amount of micro powder is generated, and the circulation stability is greatly influenced.
Therefore, the invention achieves the following technical effects by introducing the additive into the precursor: firstly, the growth of single crystal particles is promoted, and the single crystal sintering temperature is further reduced; and secondly, the uniformity of the single crystal particles is improved, the particle size distribution condition of the single crystal particles is improved, the generation of small particles and micro powder is reduced, the specific surface is reduced, and the residual alkali is reduced, so that the circulation stability is improved.
Experimental example 2
And (3) preparing the ternary single crystal cathode material prepared in the example 1 to obtain the button lithium battery. Specifically, the method comprises the following steps: and (3) carrying out electrochemical performance test by adopting a button type half-cell: the positive electrode material, the conductive carbon black and a binder PVDF (polyvinylidene fluoride) are mixed into slurry according to the ratio of 8:1:1, the slurry is coated on an aluminum foil to prepare a positive plate, a negative plate adopts a metal lithium plate, an electrolyte adopts 1mol/L LiPF6/EC: DMC (volume ratio of 1:1), and a battery shell, positive and negative electrode plates, a diaphragm, a spring plate and a gasket are assembled into a button cell in a vacuum glove box. And (4) carrying out electrochemical performance test by adopting a blue test system.
Fig. 9 is a graph of 50-cycle performance of the lithium battery under the condition of 1C, and four curves are the test curves of comparative example 1, example 2 and example 3 from top to bottom. As can be seen from fig. 9: the lithium battery is cycled for 50 weeks at 25 ℃ under 3.0V-4.4V, the capacity retention rate of the battery is 97%, and the lithium battery has high cycle performance.
While particular embodiments of the present invention have been illustrated and described, it will be appreciated that the above embodiments are merely illustrative of the technical solution of the present invention and are not restrictive; those of ordinary skill in the art will understand that: modifications may be made to the above-described embodiments, or equivalents may be substituted for some or all of the features thereof without departing from the spirit and scope of the present invention; the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention; it is therefore intended to cover in the appended claims all such alternatives and modifications that are within the scope of the invention.
Claims (10)
1. The single crystal ternary cathode material is characterized by being mainly obtained by sintering a precursor of the ternary cathode material, a lithium source and an additive;
wherein the single crystal ternary positive electrode material is LiNixCoyMnzO2X + y + z is 1, x is more than 0 and less than 1, y is more than 0 and less than 1, and z is more than 0 and less than 1; preferably, x is more than or equal to 0.5 and less than 0.9, y is more than 0.1 and less than 0.4, and z is more than 0.1 and less than 0.4;
the crystallinity of the precursor is 60-70%, and the crystallinity of the single crystal ternary cathode material is 80-90%;
the additive comprises one or more of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B compounds.
2. The single-crystal ternary cathode material according to claim 1, wherein the Span of the precursor is 1-1.5;
preferably, D of the precursor50The value is 3.0 to 4.5. mu.m.
3. The single crystal ternary cathode material according to claim 1, wherein the Span of the single crystal ternary cathode material is 0.7-1.4;
preferably, D of the single-crystal ternary cathode material503.0 to 4.5 μm;
preferably, the single crystal ternary cathode material has a BET of 0.3m2/g～0.6m2/g。
4. The single crystal ternary cathode material according to claim 1, wherein the ratio of Span of the single crystal ternary cathode material to the precursor is 0.7-0.9.
5. The single crystal ternary cathode material according to claim 1, wherein the additive is 0.05-0.6% by mass of the precursor.
6. The preparation method of the single crystal ternary cathode material is characterized by comprising the following steps of:
mixing a precursor of the single crystal ternary cathode material with the crystallinity of 60-70%, a lithium source and an additive, and then sintering in an oxygen-containing atmosphere to obtain the single crystal ternary cathode material with the crystallinity of 80-90%;
wherein the single crystal ternary positive electrode material is LiNixCoyMnzO2X + y + z is 1, x is more than 0 and less than 1, y is more than 0 and less than 1, and z is more than 0 and less than 1; preferably, x is more than or equal to 0.5 and less than 0.9, y is more than 0.1 and less than 0.4, and z is more than 0.1 and less than 0.4;
the additive comprises one or more of Sr, Ca, Mg, Al, Zr, Y, Nb, W and B compounds.
7. The method for preparing a single-crystal ternary cathode material according to claim 6, wherein the additive is 0.05 to 0.6% by mass of the precursor.
8. The method for producing a single-crystal ternary positive electrode material according to claim 6, wherein the sintering comprises:
heating to 400-650 ℃ at the heating rate of 2-10 ℃/min for the first sintering, and then heating to 700-1000 ℃ at the heating rate of 2-10 ℃/min for the second sintering.
9. The method for preparing the single crystal ternary cathode material according to claim 8, wherein the time for the first sintering is 2 to 6 hours;
and/or; the time of the second sintering is 10-15 h.
10. A lithium ion battery, comprising the single crystal ternary cathode material as defined in any one of claims 1 to 5, or the single crystal ternary cathode material prepared by the preparation method of the single crystal ternary cathode material as defined in any one of claims 6 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111627186.XA CN114335508A (en) | 2021-12-28 | 2021-12-28 | Single-crystal ternary cathode material, preparation method thereof and lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111627186.XA CN114335508A (en) | 2021-12-28 | 2021-12-28 | Single-crystal ternary cathode material, preparation method thereof and lithium ion battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114335508A true CN114335508A (en) | 2022-04-12 |
Family
ID=81014489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111627186.XA Pending CN114335508A (en) | 2021-12-28 | 2021-12-28 | Single-crystal ternary cathode material, preparation method thereof and lithium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114335508A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115241451A (en) * | 2022-09-19 | 2022-10-25 | 长虹三杰新能源(苏州)有限公司 | Lithium ion positive electrode material with low impedance and high rate cycle and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108172819A (en) * | 2017-12-18 | 2018-06-15 | 佛山市德方纳米科技有限公司 | The method of low temperature preparation monocrystalline ternary material and monocrystalline ternary material |
| CN110718688A (en) * | 2019-09-19 | 2020-01-21 | 广东邦普循环科技有限公司 | Single crystal ternary positive electrode material and preparation method thereof |
| CN111540890A (en) * | 2020-05-09 | 2020-08-14 | 宁夏中化锂电池材料有限公司 | Nickel cobalt lithium manganate ternary cathode material and preparation method thereof |
| CN112768685A (en) * | 2021-04-09 | 2021-05-07 | 湖南长远锂科股份有限公司 | Long-cycle and high-power lithium ion battery cathode material and preparation method thereof |
| CN112939095A (en) * | 2021-01-29 | 2021-06-11 | 陕西煤业化工技术研究院有限责任公司 | Spherical high-nickel cobalt-free single crystal precursor and preparation method thereof |
-
2021
- 2021-12-28 CN CN202111627186.XA patent/CN114335508A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108172819A (en) * | 2017-12-18 | 2018-06-15 | 佛山市德方纳米科技有限公司 | The method of low temperature preparation monocrystalline ternary material and monocrystalline ternary material |
| CN110718688A (en) * | 2019-09-19 | 2020-01-21 | 广东邦普循环科技有限公司 | Single crystal ternary positive electrode material and preparation method thereof |
| CN111540890A (en) * | 2020-05-09 | 2020-08-14 | 宁夏中化锂电池材料有限公司 | Nickel cobalt lithium manganate ternary cathode material and preparation method thereof |
| CN112939095A (en) * | 2021-01-29 | 2021-06-11 | 陕西煤业化工技术研究院有限责任公司 | Spherical high-nickel cobalt-free single crystal precursor and preparation method thereof |
| CN112768685A (en) * | 2021-04-09 | 2021-05-07 | 湖南长远锂科股份有限公司 | Long-cycle and high-power lithium ion battery cathode material and preparation method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115241451A (en) * | 2022-09-19 | 2022-10-25 | 长虹三杰新能源(苏州)有限公司 | Lithium ion positive electrode material with low impedance and high rate cycle and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112750999B (en) | Cathode material, preparation method thereof and lithium ion battery | |
| US11345609B2 (en) | High voltage lithium nickel cobalt manganese oxide precursor, method for making the same, and high voltage lithium nickel cobalt manganese oxide cathode material | |
| CN110690416B (en) | High-nickel ternary positive electrode material for lithium secondary battery and preparation method thereof | |
| CN110931768B (en) | High-nickel monocrystal lithium ion battery positive electrode material and preparation method thereof | |
| CN110226251B (en) | Nickel active material precursor, method for producing same, nickel active material, and lithium secondary battery | |
| CN107567666B (en) | Anode active material and secondary battery including the same | |
| CN110718688A (en) | Single crystal ternary positive electrode material and preparation method thereof | |
| US20230202866A1 (en) | Single-crystal-type multi-element positive electrode material, and preparation method therefor and application thereof | |
| WO2023071409A1 (en) | Single-crystal ternary positive electrode material, preparation method therefor, and application thereof | |
| US20240150197A1 (en) | Cobalt-free high-nickel positive electrode material, preparation method therefor and use thereof | |
| CN115863625B (en) | Layered sodium ion medium-high entropy composite oxide positive electrode material | |
| CN113130901B (en) | Titanium-doped high-nickel ternary lithium ion battery positive electrode material and preparation method thereof | |
| CN113113590B (en) | Single crystal anode material with core-shell structure and preparation method thereof | |
| CN113809320A (en) | Quaternary polycrystalline positive electrode material, and preparation method and application thereof | |
| CN111777103B (en) | Method for preparing nickel-cobalt lithium aluminate anode material | |
| CN114665090A (en) | Method for preparing large-particle-size single crystal ternary cathode material at low temperature in one step | |
| CN114620777B (en) | Ultrahigh nickel ternary precursor and preparation method thereof | |
| CN114927659B (en) | Multielement positive electrode material, preparation method and application thereof | |
| CN114597378B (en) | Ultrahigh nickel polycrystalline positive electrode material and preparation method and application thereof | |
| CN113839015A (en) | Ultra-high nickel monocrystal cathode material and preparation method thereof | |
| CN116706048A (en) | Nickel-cobalt-manganese ternary positive electrode material, preparation method thereof and lithium ion battery | |
| CN113582253B (en) | Quaternary positive electrode material, and preparation method and application thereof | |
| CN115215384B (en) | High-nickel ternary precursor and preparation method thereof | |
| JP5206948B2 (en) | Cobalt oxyhydroxide particle powder and method for producing the same | |
| CN114335508A (en) | Single-crystal ternary cathode material, preparation method thereof and lithium ion battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |