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CN-122000362-A - Composite current collector, preparation method thereof and non-negative sodium ion battery comprising composite current collector

CN122000362ACN 122000362 ACN122000362 ACN 122000362ACN-122000362-A

Abstract

The disclosure relates to the technical field of sodium secondary batteries, in particular to a composite current collector, a preparation method thereof and a negative-electrode-free sodium ion battery comprising the same. The composite current collector comprises a three-dimensional porous metal skeleton and an artificial SEI layer arranged on at least one outer surface and a hole wall surface of the three-dimensional porous metal skeleton, wherein the artificial SEI layer comprises one or more of NaTi 2 (PO 4 ) 3 、Na 3 Zr 2 Si 2 PO 12 、NaTaO 3 or NaAlF 4 . According to the method, the adjustable ultrathin artificial SEI layer is arranged on the outer surface of the three-dimensional metal porous framework and the surface of the hole wall, so that the problems of uneven sodium metal deposition, dendrite growth and the like of the negative-electrode-free sodium ion battery are solved, and the cycle performance and the multiplying power performance of the negative-electrode-free sodium ion battery are effectively improved.

Inventors

  • LIU TONGYUAN

Assignees

  • 北京希倍动力科技有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. The composite current collector is characterized by comprising a three-dimensional porous metal framework and an artificial SEI layer arranged on at least one outer surface and a hole wall surface of the three-dimensional porous metal framework; The artificial SEI layer includes one or more of phosphate, tantalate, or fluoride; the phosphate comprises NaTi 2 (PO 4 ) 3 and/or Na 3 Zr 2 Si 2 PO 12 ; The tantalate comprises NaTaO 3 ; The fluoride includes NaAlF 4 .
  2. 2. The composite current collector of claim 1 wherein said three-dimensional porous metal skeleton comprises a three-dimensional porous aluminum skeleton.
  3. 3. The composite current collector of claim 1 or 2, wherein the three-dimensional porous metal skeleton has a porosity of 20-60%; preferably, the three-dimensional porous metal skeleton has micropores and macropores; Preferably, the pore size of the micropores is 0.1-2 μm; Preferably, the pore size of the macropores is 5-20 μm; preferably, in the three-dimensional porous metal skeleton, the micropore volume accounts for 40-60% of the total pore volume; preferably, in the three-dimensional porous metal skeleton, the macropore volume accounts for 40-60% of the total pore volume; Preferably, in the three-dimensional porous metal skeleton, the pore morphology comprises open pores; Preferably, the pore wall surface roughness of the micropores and macropores is each independently 0.5 to 2.0 μm.
  4. 4. A composite current collector according to any one of claims 1-3, wherein the artificial SEI layer has a thickness of 1-25nm, preferably 5-12nm; preferably, the thickness deviation of the artificial SEI layer is within + -0.5 nm.
  5. 5. The composite current collector of claim 4, wherein a ratio of a thickness of the artificial SEI layer to an average pore diameter of the three-dimensional porous metal skeleton is 0.005 to 0.05.
  6. 6. A method of preparing a composite current collector according to any one of claims 1 to 5, comprising the steps of: (1) Carrying out porous structure construction on a metal substrate by adopting an electrochemical corrosion method to obtain a three-dimensional porous metal framework; (2) Atomic layer deposition is carried out on at least one outer surface of the three-dimensional porous metal skeleton and the surface of the hole wall to form an artificial SEI layer precursor; (3) And after the atomic layer deposition is completed, annealing treatment is carried out in an inert atmosphere, so that the composite current collector is obtained.
  7. 7. The method according to claim 6, wherein the electrochemical corrosion method in step (1) comprises performing electrochemical corrosion in an acidic solution containing halogen ions under alternating current with the metal substrate as an anode and a platinum sheet as a cathode to obtain a three-dimensional porous metal skeleton; preferably, the current density of the alternating current is 0.1-1.6A/cm 2 ; Preferably, the frequency of the alternating current is 40-60Hz; Preferably, the components of the acidic solution containing halogen ions include hydrochloric acid, sulfuric acid and chloride salts; preferably, the composition of the acidic solution containing halogen ions further comprises phosphoric acid; Preferably, the components of the acidic solution containing halogen ions comprise 0.01-0.5wt% hydrochloric acid, 0.01-0.5wt% sulfuric acid, and 0.1-0.5wt% chloride salt; preferably, the electrochemical corrosion temperature is 30-80 ℃; preferably, the electrochemical etching time is 10 to 60 seconds.
  8. 8. The method of claim 6 or 7, wherein the atomic layer deposition in step (2) has a deposition temperature of 100-300 ℃; Preferably, the annealing temperature of step (3) is 300-500 ℃; Preferably, the annealing time in step (3) is 1-2 hours.
  9. 9. A non-negative sodium ion battery, comprising a positive electrode plate, a diaphragm and electrolyte, and further comprising the composite current collector according to any one of claims 1 to 5 or the composite current collector prepared by the preparation method according to claims 6 to 8; the composite current collector is a negative current collector.
  10. 10. The negative-electrode-free sodium ion battery of claim 9, wherein the positive electrode sheet comprises a positive electrode active material comprising a sodium-containing compound; Preferably, the porosity of the diaphragm is 42% -50% and the air permeability is 150-240s/100mL.

Description

Composite current collector, preparation method thereof and non-negative sodium ion battery comprising composite current collector Technical Field The disclosure relates to the technical field of sodium secondary batteries, in particular to a composite current collector, a preparation method thereof and a negative-electrode-free sodium ion battery comprising the same. Background The negative electrode-free sodium ion battery is a novel sodium ion battery structure, does not contain negative electrode active substances in an initial state, but transfers sodium ions from a positive electrode to a negative electrode through electrochemical reduction reaction in a first charging process, and forms sodium metal on the surface of a negative electrode current collector to serve as the negative electrode active substances. The design has a plurality of remarkable advantages, such as simplifying the battery structure, reducing the cost, improving the energy density and being expected to promote the wide application of the sodium ion battery in the energy storage field. However, negative-electrode-free sodium ion batteries also face a number of technical challenges that need to be addressed. On the one hand, the deposition process of sodium metal on the surface of the negative electrode current collector is often uneven, and sodium dendrites are easy to form. These sodium dendrites not only reduce the cycle life of the battery, but may also puncture the battery separator, causing the battery to short circuit, causing serious safety accidents. On the other hand, the deposition and stripping process of sodium metal on the surface of the negative electrode current collector is accompanied by huge volume change, which can cause damage to the electrode structure, thereby affecting the cycle stability and charge-discharge performance of the battery. At present, researchers try to solve the problem of uneven sodium deposition by constructing a three-dimensional current collector structure, and the active sodium layer is formed by plating sodium on the negative electrode current collector when the negative electrode sodium ion battery is charged for the first time, so that the geometrical structure of the negative electrode current collector directly determines the nucleation site density of sodium metal, the volume change buffering capacity in the deposition/stripping process, dendrite generation probability and ion-electron transmission impedance, compared with the traditional two-dimensional planar foil (aluminum foil and copper foil), the three-dimensional porous current collector expands a deposition place from a two-dimensional surface to a three-dimensional space through a three-dimensional design, and brings unique advantages, however, the traditional three-dimensional current collector still has synergetic defect in the aspect of hole structure-interface integration, ①, wherein the aperture current density is concentrated, so that sodium metal is preferentially deposited on the surface of the current collector, cannot go deep into the inside of a pore channel, the aperture is blocked by a sodium bridge when the surface capacity is more than 2mAh cm -2, the existing ② interface layer is formed through wet coating or in-situ electrochemical conversion, the thickness is uneven (sigma > +/-20 nm), the three-dimensional aperture of 0.1-20 mu m cannot be covered, the ion conductivity of ③ interface layer is generally lower than 1×10, and the local polarization ratio of dendrite is 34 is induced at high. Therefore, a synergistic solution for simultaneously realizing three-dimensional finite field deposition and conformal high-conductivity interface is needed to break through the energy density-cycle life bottleneck of the negative-electrode-free sodium ion battery. Disclosure of Invention In order to solve the technical problems, the present disclosure provides a composite current collector, a preparation method thereof and a negative-electrode-free sodium ion battery comprising the same. In a first aspect, the present disclosure provides a composite current collector comprising a three-dimensional porous metal skeleton and an artificial SEI layer disposed on at least one outer surface and a pore wall surface of the three-dimensional porous metal skeleton; The artificial SEI layer includes one or more of phosphate, tantalate, or fluoride; the phosphate comprises NaTi 2(PO4)3 and/or Na 3Zr2Si2PO12; The tantalate comprises NaTaO 3; The fluoride includes NaAlF 4. According to the method, the adjustable ultrathin artificial Solid Electrolyte Interface (SEI) layer is arranged on the outer surface of the three-dimensional metal current collector and the surface of the hole wall, so that the problems of uneven deposition, dendrite growth and the like of sodium metal of the negative-electrode-free sodium ion battery are solved, and the cycle performance and the multiplying power performance of the negative-electrode-free sodium io