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CN-122025639-A - Positive plate and lithium ion battery using same

CN122025639ACN 122025639 ACN122025639 ACN 122025639ACN-122025639-A

Abstract

The application particularly discloses a positive plate and a lithium ion battery using the same. The positive plate comprises a current collector, an undercoat layer and a positive electrode active material layer, wherein the undercoat layer and the positive electrode active material layer are sequentially arranged on at least one surface of the current collector, the undercoat layer is positioned between the current collector and the positive electrode active material layer, lanthanum fluoride nano particles and lithium aluminum titanium phosphate are contained in the undercoat layer, and the positive electrode active material layer comprises a ternary active material. The application has the dynamic performance of the high-nickel lithium battery and can obviously improve the high-temperature resistance of the high-nickel lithium battery.

Inventors

  • WAN FENG
  • WANG WENXING
  • LI XUEFA

Assignees

  • 扬州纳力新材料科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260316

Claims (10)

  1. 1. The positive plate is characterized by comprising a current collector, an undercoat layer and a positive electrode active material layer, wherein the undercoat layer and the positive electrode active material layer are sequentially arranged on at least one surface of the current collector, and the undercoat layer is positioned between the current collector and the positive electrode active material layer; the primer layer comprises lanthanum fluoride nano particles and lithium aluminum titanium phosphate; the positive electrode active material layer includes a high nickel ternary active material.
  2. 2. The positive electrode sheet according to claim 1, wherein the lanthanum fluoride nanoparticles have a particle diameter of 30nm to 50nm and a specific surface area of 40 to 60m 2 /g.
  3. 3. The positive electrode sheet of claim 1, wherein the lithium aluminum titanium phosphate has a chemical formula of Li 1+ x Al x Ti 2-x (PO 4 ) 3 , and x has a value of 0.3 to 0.5.
  4. 4. The positive electrode sheet according to claim 1, wherein the mass ratio of the lanthanum fluoride nano particles in the undercoat layer is 6% -7%.
  5. 5. The positive electrode sheet according to claim 1, wherein the mass ratio of the lithium aluminum titanium phosphate in the undercoat layer is 20% -22%.
  6. 6. The positive electrode sheet according to claim 1, wherein the surface density of the undercoat layer is 3 to 5g/m 2 , and/or the surface density of the positive electrode active material layer is 160 to 200g/m 2 .
  7. 7. The positive electrode sheet according to any one of claims 1 to 6, wherein the undercoat layer is formed by drying an undercoat slurry, the undercoat slurry comprising a binder, a solvent, a conductive agent, the lanthanum fluoride nanoparticle, the lithium aluminum titanium phosphate.
  8. 8. The positive electrode sheet according to claim 7, wherein the primer slurry has a solid content of 20% to 22%.
  9. 9. The positive electrode sheet according to claim 7, wherein the primer paste is prepared by a method comprising the steps of: S1, mixing and stirring the binder and the solvent to obtain a glue solution; s2, mixing and stirring the conductive agent and the glue solution to obtain a conductive agent glue solution; and S3, mixing and stirring the lanthanum fluoride nano particles, the lithium aluminum titanium phosphate and the conductive glue solution to obtain the primer paste.
  10. 10. A lithium ion battery, characterized by comprising a negative plate, a diaphragm, an electrolyte and the positive plate according to any one of claims 1-9.

Description

Positive plate and lithium ion battery using same Technical Field The application relates to the technical field of lithium batteries, in particular to a positive plate and a lithium ion battery using the positive plate. Background The high-nickel ternary material (nickel content is more than or equal to 80%) has become a main current positive electrode material route in the field of high-end power batteries due to high energy density and excellent multiplying power performance. However, with the increase of nickel content, the thermal stability and interface stability of the material are remarkably deteriorated, namely, the high nickel material is easy to generate lattice oxygen release, transition metal ion dissolution and surface residual alkali reaction under the working conditions of high temperature and high voltage, so that the side reaction of the anode/electrolyte interface is aggravated, and the cycle life of the battery is greatly reduced. Therefore, how to improve the high temperature resistance of the nickel-metal batteries is a core technical problem to be broken through in the current industry. Disclosure of Invention In order to solve the problems in the prior art, the application provides a positive plate and a lithium ion battery using the same. In a first aspect, the present application provides a positive electrode sheet, which adopts the following technical scheme: The positive plate comprises a current collector, an undercoat layer and a positive electrode active material layer, wherein the undercoat layer and the positive electrode active material layer are sequentially arranged on at least one surface of the current collector, the undercoat layer is positioned between the current collector and the positive electrode active material layer, lanthanum fluoride nano particles and lithium aluminum titanium phosphate are included in the undercoat layer, and the positive electrode active material layer comprises a high-nickel ternary active material. Preferably, the nickel element content of the high-nickel ternary material is more than or equal to 80%. The application introduces a primer layer containing lanthanum fluoride nano particles and lithium aluminum titanium phosphate between a current collector and a nickel-containing positive electrode by adopting a composite structure of the current collector, the primer layer and the positive electrode active material layer. The lanthanum fluoride nano particles in the bottom coating can capture HF generated by electrolyte decomposition in the circulating process, so that corrosion of HF to a nickel-containing positive electrode and nickel ion dissolution caused by the HF can be fundamentally inhibited, meanwhile, the lanthanum fluoride nano particles can induce formation of a stable CEI film rich in LiF on the surface of the positive electrode, the interface film has high interface stability and low electron conductivity, side reactions of a positive electrode/electrolyte interface at high temperature can be effectively inhibited, meanwhile, lithium aluminum titanium phosphate is used as a fast ion conductor, a high-speed lithium ion transmission channel is constructed in the bottom coating, the defect of low electronic/ionic conductivity of lanthanum fluoride is overcome, and the bottom coating is ensured not to limit the kinetic performance of a battery due to the introduction of the lanthanum fluoride nano particles. In addition, the compact bottom coating is also used as a physical barrier to inhibit the release of lattice oxygen and the dissolution of transition metal ions of the nickel-containing material under high pressure and high temperature, so that the high-temperature cycle stability and the thermal runaway tolerance of the battery are obviously improved on the premise of ensuring the normal transmission of lithium ions, and the high-temperature storage performance of the lithium battery is facilitated to be improved. Preferably, the particle size of the lanthanum fluoride nano particles is 30nm-50nm, and the specific surface area is 40-60 m 2/g. This specific surface area range ensures good dispersibility of the lanthanum fluoride nanoparticles in the primer layer while providing sufficient active sites for capturing HF and participating in the film forming reaction of the CEI film. When the specific surface area is too low, the particle size is too large, HF capture sites of unit mass are insufficient, continuous and compact LiF interface layers are difficult to induce to form on the surface of the positive electrode, and when the specific surface area is too high, nano particles are extremely easy to agglomerate, and instead, local defects of the bottom coating are increased, and poor interface contact is caused. The lanthanum fluoride adopted by the application can realize the ionic conductivity of more than 10 -5 S/cm (25 ℃) in the specific surface area interval, and combines high reactivity and good processing dispersibilit