Search

CN-122025648-A - Lithium dendrite suppression type negative current collector with spherical whole-domain bidirectional Schottky rectifying junction and preparation method thereof

CN122025648ACN 122025648 ACN122025648 ACN 122025648ACN-122025648-A

Abstract

The invention discloses a rectifying microsphere for a lithium ion battery negative electrode current collector, the negative electrode current collector and a preparation method thereof, and belongs to the technical field of lithium ion batteries. The rectifying microsphere comprises an N-type heavily doped zinc oxide semiconductor core, a high copper brass alloy permeation layer is thermally permeated on the surface of the core, and a surrounding type bidirectional Schottky rectifying junction is formed at the interface of the N-type heavily doped zinc oxide semiconductor core and the high copper brass alloy permeation layer. The negative current collector adopts a structure of a copper foil substrate, a conductive adhesive bottom layer, an insulating adhesive wrapping layer, a rectifying microsphere and a surface conductive carbon adhesive layer, and the insulating adhesive wraps the side wall of the rectifying microsphere to block an electronic bypass, so that electrons are transmitted through a bidirectional Schottky rectifying junction preferentially. The invention realizes ion guiding and electronic hysteresis by reverse controllable conduction of the rectifying junction during charging, fundamentally inhibits the growth of lithium dendrite, and has forward low resistance and free flow during discharging without influencing the multiplying power performance of the battery. The process disclosed by the invention is compatible with the existing lithium electric quantity production line, has low cost and stable structure, and can greatly improve the safety, the cycle life and the quick charge performance of the lithium battery.

Inventors

  • LEI YONG

Assignees

  • 雷勇

Dates

Publication Date
20260512
Application Date
20260326

Claims (20)

  1. 1. The rectifying microsphere for the lithium ion battery negative electrode current collector is characterized by comprising an N-type heavily doped zinc oxide semiconductor core, wherein a high copper brass alloy permeation layer is thermally permeated on the outer surface of the core, and a surrounding bidirectional Schottky rectifying junction is formed at the interface of the N-type heavily doped zinc oxide semiconductor core and the high copper brass alloy permeation layer.
  2. 2. A lithium ion battery negative electrode current collector, which comprises a copper foil substrate, a conductive adhesive bottom layer and a surface conductive carbon adhesive layer, and is characterized by further comprising the rectifying microsphere and insulating adhesive wrapping layer in claim 1; The bottom of the rectifying microsphere is in conductive contact with the bottom layer of the conductive adhesive, and the top of the rectifying microsphere is in conductive contact with the surface conductive carbon adhesive layer; the insulating adhesive coating is electrolyte-resistant insulating adhesive and is coated on the side wall of the rectifying microsphere to block bypass transmission of electrons, so that the electrons are transmitted by the bidirectional Schottky rectifying junction of the rectifying microsphere preferentially.
  3. 3. The preparation method of the lithium ion battery negative electrode current collector comprises the steps of copper foil pretreatment, conductive adhesive bottom coating and surface conductive carbon adhesive layer preparation, and is characterized by further comprising the following steps: (1) Preparing rectifying microspheres, namely uniformly mixing N-type heavily doped zinc oxide microspheres with high copper brass powder, and performing vacuum thermal infiltration treatment to obtain the rectifying microspheres of claim 1; (2) Coating an insulating adhesive, namely coating electrolyte-resistant insulating adhesive on the surface of a conductive adhesive bottom layer, and drying to a semi-solidified surface dry state; (3) Microsphere lamination, namely pressing the rectifying microsphere into the semi-cured insulating adhesive layer to enable the bottom of the rectifying microsphere to be in conductive contact with the bottom layer of the conductive adhesive; (4) The electric field auxiliary glue wrapping is to apply a direct current electric field to the rectifying microsphere to lead the insulating glue to be adsorbed and wrapped on the side wall of the rectifying microsphere in a directional way; (5) And (3) curing and forming, namely preparing a surface conductive carbon adhesive layer after the insulating adhesive is completely cured, and rolling and forming to obtain the negative electrode current collector.
  4. 4. A lithium ion battery comprising the lithium ion battery anode current collector of claim 2.
  5. 5. A battery module comprising at least one lithium ion battery of claim 4.
  6. 6. A battery pack comprising at least one battery module according to claim 5.
  7. 7. An electric device, comprising at least one selected from the group consisting of the lithium ion battery of claim 4, the battery module of claim 5, and the battery pack of claim 6.
  8. 8. The rectifying microsphere according to claim 1, wherein the N-type heavily doped zinc oxide semiconductor core is a zinc oxide microsphere doped with trivalent elements, the trivalent elements are any one or a combination of a plurality of Al, ga and In, and the doping mass ratio of the trivalent elements is 0.5% -2%.
  9. 9. The rectifying microsphere of claim 1, wherein the N-type heavily doped zinc oxide semiconductor core has an average particle size of 1 μm to 5 μm.
  10. 10. The rectifying microsphere according to claim 1, wherein the high copper brass alloy infiltrated layer is a copper zinc alloy layer of Cu80Zn 20-Cu 90Zn10, and the thickness of the alloy infiltrated layer is 20 nm-200 nm.
  11. 11. The rectifying microsphere according to claim 1, wherein the outer surface of the rectifying microsphere is further provided with a passivation layer, and the passivation layer is Al And the thickness of the passivation layer is 1 nm-2 nm in any one of O 3 、ZrO 2 、HfO 2 .
  12. 12. The rectifying microsphere according to claim 1, wherein the forward conduction opening voltage of the bidirectional schottky rectifying junction is 0.3-0.4V, the reverse conduction triggering voltage is 0.8-1.1V, in a reverse bias interval of 1.0-1.8V, the conduction current is amplified by 2.5-5 times when the bias voltage is increased by 0.1V, and the conduction current tends to be saturated when the reverse bias voltage is more than or equal to 2.0V.
  13. 13. The negative current collector of claim 2, wherein the depth of the rectifying microsphere pressed into the insulating glue coating is 60% -80% of the particle size of the rectifying microsphere.
  14. 14. The negative electrode current collector according to claim 2, wherein the electrolyte-resistant insulating glue of the insulating glue wrapping layer is any one of fluorine-modified acrylate glue and butyl rubber glue.
  15. 15. The negative current collector of claim 2, wherein the insulating glue of the insulating glue wrapping layer is mixed with nano soft magnetic powder, and the addition mass ratio of the nano soft magnetic powder is 5% -10% of the dry weight of the insulating glue.
  16. 16. The negative current collector of claim 2, wherein the surface conductive carbon gel layer is prepared by a low-pressure atomization spraying process, and the dry film thickness of the surface conductive carbon gel layer is 0.5-1 μm.
  17. 17. The preparation method according to claim 3, wherein in the step (1), the vacuum degree of the vacuum thermal infiltration treatment is less than or equal to 10Pa, the treatment temperature is 100-150 ℃, and the heat preservation time is 1-3 h.
  18. 18. The method according to claim 3, wherein in the step (2), the semi-cured surface dry state is a wiredrawing surface dry state, and the drying temperature is 60 ℃ to 90 ℃.
  19. 19. The method according to claim 3, wherein in the step (3), smooth press rolls are used for pressing in a state of no power, the pressing depth is 60% -80% of the particle size of the rectifier microsphere, and the press rolls are kept stand for 1 s-2 s after pressing and are stable.
  20. 20. The method of claim 3, wherein in the step (4), the direct current electric field is applied in such a manner that the pressing roller is connected with the positive electrode of the direct current power supply, the copper foil substrate is connected with the negative electrode of the direct current power supply, the applied direct current voltage is 1-5V, and the energizing time is 1-10 s.

Description

Lithium dendrite suppression type negative current collector with spherical whole-domain bidirectional Schottky rectifying junction and preparation method thereof Technical Field The invention belongs to the technical field of lithium ion batteries, and particularly relates to a negative electrode current collector structure capable of controlling negative electrode electron transport time sequence through a layered glue layer structure matched with a spherical semiconductor rectifying junction and inhibiting growth of lithium dendrite from a root source and a preparation process. Definition of terms In the description and claims of the present invention, the following terms have the following meanings, unless explicitly indicated otherwise: 1. The bidirectional Schottky rectifying junction is a metal-semiconductor rectifying junction which is formed by contacting metal (high copper brass alloy) with an N-type semiconductor (heavily doped zinc oxide) and has bidirectional rectifying characteristics, and can be equivalently expressed as a bidirectional PN junction in the specification. 2. The semi-cured surface dry state refers to a state that the adhesive layer has viscosity and wiredrawing characteristics after being dried, can deform without rebound, but does not have complete cross-linking and curing. 3. And the electron bypass transmission refers to the phenomenon that electrons are directly transmitted between the conductive adhesive bottom layer and the surface conductive carbon adhesive layer through an insulating adhesive layer or other paths without passing through a bidirectional Schottky rectifying junction. Background Lithium ion batteries have become the mainstream electrochemical energy storage devices in the fields of power, energy storage and consumer electronics due to the advantages of high energy density, long cycle life, no memory effect and the like. However, since commercialization, the problem of lithium dendrite growth has been a core industry pain point that limits lithium battery safety, cycle life and fast charge performance. In the prior art, the schemes for solving the problem of lithium dendrites are mainly divided into three types, and the defects of the bottom layer which cannot be overcome are all existed: 4. modification of the cathode material, namely improving the lithium ion intercalation environment by means of artificial graphite optimization, silicon-carbon compounding, surface coating and the like, wherein the method can only relieve dendrite growth and does not reach the core root of dendrite generation; 5. The electrolyte additive is optimized, namely an SEI film is formed on the surface of the negative electrode through a film forming additive, dendrite growth is restrained, but the SEI film can be continuously aged and broken along with circulation, the circulation service life is limited, and the internal resistance and the sacrifice rate performance of a battery can be improved; 6. The solid electrolyte is used for replacing the inorganic solid electrolyte to block dendrite puncture, but the problems of high interface impedance, extremely high cost, high mass production difficulty, poor bending resistance and the like exist, and the solid electrolyte cannot be popularized on a large scale. In all the schemes, the essential contradiction of the bottom layer generated by lithium dendrites is not solved, in the charging process, the transport speed of electrons is light speed level, the migration speed of lithium ions is minute level, huge time sequence difference exists between the electron and the electron, the electron is enriched on the surface of negative graphite in advance, and is directly paired with the lithium ions migrating to the surface for reduction to generate metal lithium, and finally dendrites grow. In the prior art, zinc oxide is only used as a lithium battery cathode active material, lithium is stored by utilizing the lithium intercalation characteristic of the zinc oxide, the zinc oxide is not used for preparing a semiconductor rectifying junction to regulate and control the electronic time sequence, a Schottky rectifying junction is only used for a discrete electronic device and is not integrated in a lithium battery cathode current collector, the zinc oxide is not used for related application of a spherical whole-domain bidirectional rectifying junction, and the matching process of blocking an electronic bypass through insulating glue, assisting in wrapping glue by an electric field and atomizing and spraying carbon glue is not used. Disclosure of Invention The invention discloses a protection scope, which not only comprises the lithium ion battery cathode current collector, but also comprises a core rectifying microsphere for preparing the current collector, a preparation method of the cathode current collector, a lithium ion battery, a battery module, a battery pack and electric equipment using the lithium ion battery, the battery module o