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CN-121983553-A - High-nickel positive electrode material, preparation method thereof and solid-state battery

CN121983553ACN 121983553 ACN121983553 ACN 121983553ACN-121983553-A

Abstract

The invention relates to a high-nickel positive electrode material, a preparation method thereof and a solid-state battery. The high-nickel positive electrode material comprises a high-nickel inner core, and a LiAlO 2 coating layer and a Li 3 PO 4 coating layer which are sequentially formed on the surface of the high-nickel inner core in situ, wherein the median particle diameter D50 of the high-nickel inner core is 5-12 mu m. According to the invention, the gradient-distributed LiAlO 2 /Li 3 PO 4 composite coating layer is constructed on the surface of the high-nickel core in situ, so that when the lithium-ion-doped lithium-ion-battery is applied to the sulfide solid electrolyte, the transmission of lithium ions is effectively optimized, and the side reaction between the high-nickel core and the sulfide solid electrolyte can be thoroughly inhibited, so that the first effect, the multiplying power performance and the cycle performance of the solid-state battery are improved.

Inventors

  • XU KAIHUA
  • LIU HAI
  • WANG YANING
  • ZHANG KUN
  • WU YULOU
  • CHEN HUANHUI
  • ZHOU ZHICONG
  • Zhang Zhuolun
  • LIANG LI

Assignees

  • 格林美股份有限公司
  • 格林美(深圳)超级绿色技术研究中心有限公司

Dates

Publication Date
20260505
Application Date
20260226

Claims (10)

  1. 1. The high-nickel positive electrode material is characterized by comprising a high-nickel inner core, and a LiAlO 2 coating layer and a Li 3 PO 4 coating layer which are sequentially formed on the surface of the high-nickel inner core in situ; The median particle diameter D50 of the high nickel core is 5-12 mu m.
  2. 2. The high nickel positive electrode material according to claim 1, wherein the LiAlO 2 comprises gamma-phase LiAlO 2 ; And/or, in the high-nickel positive electrode material, the total mass percentage of the LiAlO 2 coating layer and the Li 3 PO 4 coating layer is 0.5-2.5 wt%.
  3. 3. A method for producing the high nickel positive electrode material according to claim 1 or 2, characterized by comprising: Mixing a high-nickel precursor, a lithium source and AlPO 4 powder, and sequentially performing first-stage sintering and second-stage sintering to prepare the high-nickel anode material; The molar ratio of Li in the lithium source to transition metal element TM in the high-nickel precursor is 1.03-1.10.
  4. 4. The method according to claim 3, wherein the average particle size of the AlPO 4 powder is 20nm to 200nm; And/or the mass of the AlPO 4 powder is 0.5wt.% to 2.5wt.% of the mass of the high nickel precursor.
  5. 5. The method of claim 3 or 4, wherein the first stage sintering and the second stage sintering each independently have a temperature rise rate of 2 ℃ per minute to 5 ℃ per minute; And/or, the first stage sintering and the second stage sintering are each independently performed under an oxygen-containing atmosphere; And/or the temperature of the first-stage sintering is 450-550 ℃; and/or the sintering time of the first section is 2-6 hours; And/or the temperature of the second-stage sintering is 700-850 ℃; And/or the second-stage sintering time is 10-20 h.
  6. 6. The method according to any one of claims 3 to 5, wherein the mixing means comprises ball milling at 300rpm to 500rpm; And/or, the preparation method further comprises grinding and sieving the high-nickel anode material, wherein the number of the sieves used for sieving is 200-400 meshes.
  7. 7. A solid-state battery, characterized in that the solid-state battery comprises the high-nickel positive electrode material according to claim 1 or 2; The solid-state battery also comprises a lithium ion conductor gradient interface layer which is formed in situ between the surface of the high-nickel positive electrode material and the sulfide solid-state electrolyte through activation treatment; the gradient interface layer of the lithium ion conductor is made of a Li-Al-P-O-S lithium ion conductor phase or a Li-Al-S-O lithium ion conductor phase.
  8. 8. The solid state battery of claim 7, wherein the lithium ion conductor gradient interface layer has a thickness of 5nm to 50nm.
  9. 9. The solid-state battery according to claim 7, wherein the activation treatment comprises constant-current charging of the solid-state battery to an activation voltage, then constant-voltage charging to an off-current, and continuing to hold at the activation voltage until activation is completed.
  10. 10. The solid-state battery according to claim 9, wherein the constant current charge rate is 0.02c to 0.1c; And/or the activation voltage is 4.4V-4.8V; And/or the cut-off current is 0.002C-0.01C; and/or the holding time is 1-24 h.

Description

High-nickel positive electrode material, preparation method thereof and solid-state battery Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a solid-state battery, and especially relates to a high-nickel positive electrode material, a preparation method thereof and the solid-state battery. Background High nickel layered oxide positive electrode materials with a molar ratio of nickel in the transition element higher than 80%, such as nickel cobalt lithium manganate (NCM), nickel cobalt lithium aluminate (NCA), etc., are key to realizing next generation high energy density lithium ion batteries. However, when it is matched with sulfide solid electrolyte (SSE such as Li 6PS5Cl、Li10GeP2S12) and applied to all-solid-state battery (ASSB), there are two major core problems that firstly serious side reaction of interface is caused, the strong oxidizing property of the charged high-nickel positive electrode oxidizes the sulfide electrolyte to generate an electron/ion insulating layer such as Li 2S、Li3 P and elemental sulfur, so that interface impedance is increased rapidly and capacity is attenuated rapidly, and secondly poor solid-solid interface contact is caused, and the point contact between the high-nickel positive electrode and the solid-state electrolyte causes poor ion transmission channel. CN119786581a discloses a coating method of high nickel layered oxide positive electrode material, which uses acid-base neutralization reaction to realize coating of high nickel layered oxide positive electrode material, the coated components include three elements, namely high valence metal, halogen element (F or Cl) with higher electronegativity and Li element, the former two coating purposes are to improve structural stability of high nickel layered oxide, the latter provides lithium source for positive electrode material, meanwhile avoids high nickel layered oxide contacting with sulfide electrolyte, inhibits side reaction, and is favorable for long cycle stability of sulfide all-solid lithium battery. CN118315557a discloses a modified high-nickel positive electrode material, a preparation method thereof and a sulfide all-solid-state battery, a layer of fast ion conductor silicate is coated on the surface of a positive electrode base material by adopting a solution method and heating treatment, and the prepared modified high-nickel positive electrode material not only avoids direct contact between a positive electrode and sulfide electrolyte and prevents accumulation of byproducts at an interface, but also accelerates lithium ion transmission at the interface, reduces interface impedance, improves lithium ion diffusion kinetics at the interface, and is beneficial to constructing the sulfide all-solid-state battery with high energy density. CN115050930A discloses a composite high-nickel layered positive electrode material, a positive electrode plate and an all-solid-state lithium battery, wherein an Al element doped high-nickel layered positive electrode material is prepared by a coprecipitation method, then a high-nickel layered positive electrode material co-coated by fluorine-containing phenylboronic acid and phosphorothioate is prepared by a spray drying method, namely the composite high-nickel layered positive electrode material, and the composite high-nickel layered positive electrode material, sulfide solid electrolyte, a conductive agent and all-trans beta PVDF are mixed and compressed to prepare the positive electrode plate and the all-solid-state lithium battery. The composite high-nickel layered positive electrode material provided by the invention effectively inhibits continuous attenuation of the high-nickel layered positive electrode material, reduces impedance, promotes internal transmission of lithium ions, can avoid direct contact of high-nickel particles with solid electrolyte, and improves cycle life and electrochemical stability of the positive electrode plate through element doping and construction of an optimized CEI film. In the prior art, a single coating strategy is adopted to alleviate the problems, so that high voltage stability and good compatibility with sulfide are difficult to be achieved, and a uniform coating process is complex and expensive. More importantly, the prior art only stays in the preparation stage of materials, and cannot actively optimize the secondary interface between the coating layer and the SSE after the battery is molded, and the interface is still a performance bottleneck and a failure source. Therefore, the strategy for providing a collaborative optimization interface from a material body to a solid-state battery preparation whole process is of great significance. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a high-nickel positive electrode material, a preparation method thereof and a solid-state battery. According to the invention, the high-nickel substra