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CN-122025529-A - Composite pole piece, preparation method thereof and battery

CN122025529ACN 122025529 ACN122025529 ACN 122025529ACN-122025529-A

Abstract

The embodiment of the application discloses a composite pole piece, a preparation method thereof and a battery. The composite pole piece comprises a current collector, a safety base coat, an ion conducting coating and an active material layer, wherein the safety base coat is arranged on the current collector and comprises ceramic particles, the ion conducting coating is arranged on one side of the safety base coat far away from the current collector and comprises solid electrolyte, the ion conductivity of the solid electrolyte is more than or equal to 10 ‑4 S/cm, and the active material layer is arranged on one side of the ion conducting coating far away from the safety base coat and comprises an active material. By additionally arranging the ion conducting coating between the safety base coat and the active material layer, the ion conducting coating is rich in solid electrolyte with the ion conductivity of more than or equal to 10 ‑4 S/cm, has strong ion transmission capacity, improves the transmission efficiency of lithium ions in the battery, and further reduces the internal resistance of the battery and improves the cycle performance.

Inventors

  • CHEN ZHIWEI
  • LIU RONGJIANG
  • HUANG BINBIN

Assignees

  • 惠州亿纬锂能股份有限公司

Dates

Publication Date
20260512
Application Date
20251231

Claims (10)

  1. 1. A composite pole piece, comprising: A current collector; A safety primer layer disposed on the current collector, the safety primer layer comprising ceramic particles; An ion conductive coating layer arranged on one side of the safety base coat far away from the current collector, wherein the ion conductive coating layer comprises solid electrolyte, the ion conductivity of the solid electrolyte is more than or equal to 10 -4 S/cm, and And an active material layer disposed on a side of the ion conductive coating remote from the safety primer layer, the active material layer including an active material.
  2. 2. The composite pole piece of claim 1, wherein the safety primer layer has a thickness of 1 μm to 5 μm, and/or, The thickness of the ion-conducting coating is 0.5-2 mu m, and/or, The thickness of the active material layer is 50-150 mu m.
  3. 3. The composite pole piece of claim 1 or 2, wherein the ceramic particles comprise at least one of alumina, magnesium hydroxide, and boehmite, and/or, The solid state electrolyte includes at least one of Li 7 La 3 Zr 2 O 12 、Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 、Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , and/or, The active material includes at least one of lithium nickel cobalt manganese oxide, lithium cobalt oxide, and lithium phosphate.
  4. 4. The composite pole piece of any one of claims 1-3, wherein the safety primer layer further comprises a first binder and a first conductive agent, wherein the ceramic particles are 80-90 wt%, the first binder is 5-10 wt%, and the first conductive agent is 3-10 wt%.
  5. 5. The composite pole piece of any of claims 1-4, wherein the ion conductive coating further comprises a second binder, wherein the solid electrolyte is present in an amount of 90wt% to 95wt%, and the second binder is present in an amount of 5wt% to 10wt%.
  6. 6. The composite pole piece of any one of claims 1-5, wherein the active material layer further comprises a third binder and a second conductive agent, wherein the active material is 90-95 wt%, the third binder is 2-5 wt%, and the second conductive agent is 2-5 wt%.
  7. 7. The composite pole piece of any of claims 1-6, wherein the composite pole piece has a compacted density of 3.2g/cm 3 ~4.2 g/cm 3 .
  8. 8. The method for preparing the composite pole piece according to any one of claims 1 to 7, comprising the steps of: Providing a current collector; providing a first slurry comprising ceramic particles and a first solvent, subjecting the first slurry to a first film forming treatment and a first drying treatment on the current collector to form a safety primer layer; providing a second slurry comprising a solid electrolyte and a second solvent, subjecting the second slurry to a second film forming treatment and a second drying treatment on the safety primer layer to form an ion-conductive coating; And providing a third slurry, wherein the third slurry comprises an active material and a third solvent, and performing third film forming treatment and third drying treatment on the ion-conducting coating to form an active material layer to obtain the composite pole piece.
  9. 9. The method of claim 8, wherein the first slurry further comprises a first binder and a first conductive agent, the first slurry has a solid content of 30wt% to 40wt%, and/or, The second slurry also comprises a second binder, the solid content of the second slurry is 20-30wt%, and/or, The third slurry further comprises a third binder and a second conductive agent, and the solid content of the third slurry is 60-75wt%.
  10. 10. A battery comprising a composite pole piece according to any one of claims 1 to 7 or a composite pole piece produced according to the method of producing a composite pole piece of claim 8 or 9.

Description

Composite pole piece, preparation method thereof and battery Technical Field The application relates to the technical field of batteries, in particular to a composite pole piece, a preparation method thereof and a battery. Background With the wide application of lithium ion batteries in the fields of 3C electronics, power and energy storage, high energy density and high safety performance become core demands. Currently, thermal stability and mechanical strength of the battery can be effectively improved and thermal runaway risks can be suppressed by coating a safety primer (such as ceramic coating and polymer coating) on the surface of the electrode. However, after the safety bottom coating is arranged, the internal resistance of the battery is obviously increased, so that the problems of cycle capacity attenuation, rate performance reduction and the like of the battery are caused. Disclosure of Invention The application provides a composite pole piece, a preparation method thereof and a battery, and aims to solve the problem that the internal resistance of the battery is obviously increased after a safety base coat is arranged. The application provides a composite pole piece, comprising: A current collector; A safety primer layer disposed on the current collector, the safety primer layer comprising ceramic particles; An ion conductive coating layer arranged on one side of the safety base coat far away from the current collector, wherein the ion conductive coating layer comprises solid electrolyte, the ion conductivity of the solid electrolyte is more than or equal to 10 -4 S/cm, and And an active material layer disposed on a side of the ion conductive coating remote from the safety primer layer, the active material layer including an active material. The composite pole piece provided by the embodiment of the application is provided with the safety base coat on the current collector, the thermal stability and the mechanical strength of the battery can be improved by utilizing the thermal barrier effect of ceramic particles in the safety base coat, and the risk of thermal runaway of the battery is reduced, and further, an ion conducting coating is additionally arranged between the safety base coat and the active material layer, wherein the ion conducting coating is rich in solid electrolyte with the ion conductivity of more than or equal to 10 -4 S/cm, has stronger ion transmission capability, and improves the transmission efficiency of lithium ions in the battery, so that the internal resistance of the battery is reduced, and the cycle performance is improved. Optionally, in some embodiments of the present application, the thickness of the safety primer layer is 1 μm to 5 μm. The thickness of the safety primer layer less than 1 μm may reduce the heat insulation effect of the safety primer layer, and the safety of the battery may be reduced, while the thickness of the safety primer layer greater than 5 μm may sharply increase the internal resistance of the battery, and the cycle performance of the battery may be reduced. Optionally, in some embodiments of the present application, the ion-conducting coating has a thickness of 0.5 μm to 2 μm. The thickness of the ion-conducting coating is smaller than 0.5 μm, so that the ion-conducting coating is difficult to uniformly cover the safety base coat, the transmission efficiency of lithium ions in the battery is affected, the thickness of the ion-conducting coating is larger than 2 μm, the lithium ion transmission path is too long, the transmission efficiency of lithium ions in the battery is also affected, the internal resistance of the battery is increased, and the cycle performance is reduced. Optionally, in some embodiments of the present application, the thickness of the active material layer is 50 μm to 150 μm. The thickness of the active material layer directly influences the energy density of the battery, and increasing the thickness of the active material layer is beneficial to improving the energy density of the battery, but too large thickness of the active material layer can increase mass transfer resistance and the infiltration effect of the electrolyte on the active material layer, so that concentration polarization is increased, and the cycle performance of the battery is deteriorated. Optionally, in some embodiments of the application, the ceramic particles comprise at least one of alumina, magnesium hydroxide, and boehmite, and/or, The solid state electrolyte includes at least one of Li7La3Zr2O12、Li1.5Al0.5Ge1.5(PO4)3、Li1.3Al0.3Ti1.7(PO4)3, and/or, The active material includes at least one of lithium nickel cobalt manganese oxide, lithium cobalt oxide, and lithium phosphate. Optionally, in some embodiments of the present application, the safety primer layer further includes a first binder and a first conductive agent, wherein the content of the ceramic particles is 80wt% to 90wt%, the content of the first binder is 5wt% to 10wt%, and the content of