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CN-121983575-A - Lithium-philic porous interface functional layer and preparation method and application thereof

CN121983575ACN 121983575 ACN121983575 ACN 121983575ACN-121983575-A

Abstract

The invention discloses a lithium-philic porous interface functional layer and a preparation method and application thereof, wherein the preparation method comprises the steps of dissolving a binder in a nonpolar solvent to form a solution A; the method comprises the steps of adding a lithium-philic porous framework material and an electronic conductor into a solution A through a water bath synthesis method, stirring and reacting to form a solution B, adding a small amount of an ion conductor into the solution B for many times to form a solution C, coating the solution C on a current collector, and drying to form a lithium-philic porous interface functional layer on the current collector. Also disclosed are a lithium-philic porous interface functional layer prepared by the preparation method, and a lithium anode comprising the functional layer. The lithium-philic porous interface functional layer comprises a lithium philic skeleton, the pore wall of the lithium philic skeleton comprises an electronic conductor, and the pore wall of the lithium philic skeleton comprises an ion conductor, so that the lithium-philic porous interface functional layer not only can limit the infinite volume expansion of lithium, but also can homogenize lithium ion flow, reduce the surface effective current density, inhibit the growth of lithium dendrites, and realize the high-capacity long-cycle performance of an all-solid-state lithium metal battery.

Inventors

  • ZHU FEI

Assignees

  • 上海屹锂新能源科技有限公司

Dates

Publication Date
20260505
Application Date
20260116

Claims (10)

  1. 1. The preparation method of the lithium-philic porous interface functional layer is characterized by comprising the following steps of: S1, dissolving a binder in a nonpolar solvent to form a solution A; S2, adding the lithium-philic porous framework material and the electronic conductor into the solution A through a water bath synthesis method, and stirring and reacting to form a solution B; S3, adding a small amount of ionic conductor into the solution B for many times to form a solution C; And S4, coating the solution C on a current collector, and drying to form a lithium-philic porous interface functional layer on the current collector.
  2. 2. The preparation method according to claim 1, wherein in the step S1, the binder is at least one selected from styrene-butadiene rubber, polypropylene carbonate, polyisobutylene, polyvinylidene fluoride; and/or the nonpolar solvent is selected from at least one of paraxylene, toluene, tetrahydrofuran and butyl ether; In the solution A, the concentration of the binder is 0.5-1.5 wt%.
  3. 3. The method of claim 1, wherein in step S2, the lithium-philic porous scaffold material comprises a carbon-based porous scaffold material or a metal-based porous scaffold material; The carbon-based porous framework material is selected from any one of porous carbon fiber, three-dimensional porous graphene, three-dimensional porous carbon nanotube and biomass-derived porous carbon; The metal-based porous framework material is selected from metal oxide porous framework materials or metal sulfide porous framework materials, the metal oxide porous framework materials are selected from any one of aluminosilicate with a micropore structure, mesoporous TiO 2 and mesoporous ZrO 2 , and the metal sulfide porous framework materials are selected from any one of MoS 2 、Zn 4 S、Mn 4 S porous framework materials.
  4. 4. The method according to claim 1, wherein in step S2, the electronic conductor is a metal conductor selected from at least one of aluminum, magnesium, indium, tungsten, silver, and tin; And/or in the step S2, the temperature of the stirring reaction is 50-60 ℃ and the time is 4-8h.
  5. 5. The method of claim 1, wherein in step S3, the ion conductor comprises an oxide solid electrolyte or a sulfide solid electrolyte; The oxide solid electrolyte is selected from at least one of Li 7 La 3 Zr 2 O 12 、Li 1+x Al x Ti 2-x (PO 4 ) 3 、Li 1+x Al x Ge 2-x (PO 4 ) 3 ; The sulfide solid state electrolyte is selected from at least one of Li 10 GeP 2 S 12 、Li 7 P 3 S 11 、Li 6 PS 5 Cl.
  6. 6. The method according to claim 1, wherein in step S4, the coating mode is selected from any one of spin coating, spray coating, and magnetron sputtering; and/or, in step S4, the current collector is selected from copper foil or stainless steel foil.
  7. 7. The lithium-philic porous interface functional layer is characterized by being prepared by adopting the preparation method according to any one of claims 1-6, and comprises a lithium-philic porous skeleton, an electronic conductor and an ion conductor, wherein the electronic conductor is uniformly dispersed on the pore wall of the lithium-philic porous skeleton, and the ion conductor is dispersed in the pores of the lithium-philic porous skeleton.
  8. 8. The lithium-philic porous interface functional layer of claim 7, wherein the mass percent of the electronic conductor in the lithium-philic porous interface functional layer is 5-20%, and the mass percent of the ion conductor in the lithium-philic porous interface functional layer is 20-50%; And/or the lithium-philic porous interface functional layer further comprises a binder, wherein the mass percentage of the binder in the lithium-philic porous interface functional layer is 0.5-2 wt%.
  9. 9. The lithium-philic porous interface functional layer of claim 7, wherein the average pore size D = 0.1-5 μιη and pore volume V = 0.1-0.5 cc/g of the lithium-philic porous scaffold; The average particle diameter D 1 = 0.01-1 μm and D 1 /D = 0.2-0.5 of the electronic conductor; The average particle diameter D 2 = 0.05-2 μm and D 2 /D = 0.5-0.8 of the ion conductor.
  10. 10. A lithium metal negative electrode modified by a lithium-philic porous skeleton, comprising the lithium-philic porous interface functional layer according to any one of claims 7-9, and further comprising a lithium foil; the thickness of the lithium-philic porous interface functional layer is 1-30 mu m, and the thickness of the lithium foil is 5-20 mu m.

Description

Lithium-philic porous interface functional layer and preparation method and application thereof Technical Field The invention relates to the technical field of lithium batteries, in particular to a lithium-philic porous interface functional layer, a preparation method and application thereof. Background Although the graphite anode has higher safety and longer cycle life, the theoretical capacity of the graphite anode is limited, so that the energy density is relatively low (about 150-250 Wh.kg -1) and the weight and the thickness are larger. Lithium metal anodes possess a higher theoretical specific capacity (mAh/g) and lower electrochemical potential than graphite anodes, and are considered one of the most potential anode materials. The application of the lithium metal cathode can obviously improve the energy density of the solid-state battery, so that the lithium metal cathode has wide application prospect in the fields of electric automobiles, energy storage systems and the like. In addition, the lithium metal negative electrode has the characteristics of high charge and discharge efficiency and high safety in a solid-state battery. Meanwhile, the thin lithium metal anode and the cathode-free configuration further reduce the weight and thickness, and significantly improve the battery energy density (up to >400 Wh-kg -1 and >500 Wh-kg -1, respectively). However, lithium metal anodes still have some problems. The SEI film formed in the circulation process has obvious non-uniformity in chemical composition, microcosmic appearance and ion conductivity. This characteristic can lead to uneven distribution of lithium ion flux and disordered distribution of nucleation sites, thereby inducing growth of lithium dendrites, and in severe cases, the phenomenon of dead lithium can occur, resulting in internal short circuit of the battery. Therefore, constructing an SEI layer having a stable structure and uniform characteristics becomes a key cut point to suppress side reactions and dendrite growth problems. In addition, lithium metal can creep under high pressure to easily cause short circuit of the battery, and under low pressure, poor contact of solid-solid interface can occur. The volume expansion effect of the lithium metal anode is serious, the interface degradation problem in the cycle is prominent, and the cycle life of the battery is greatly reduced. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a lithium-philic porous interface functional layer, a preparation method and application thereof, wherein the lithium-philic porous interface functional layer with a lithium-philic porous skeleton structure is used for modifying a lithium metal negative electrode, the pore wall of the lithium-philic porous skeleton structure is an electronic conductor, and an ion conductor is arranged in the pore. The formed porous lithium-philic skeleton can homogenize the lithium ion flux, and the skeleton can form a rapid lithium diffusion path to convert the deposition/stripping process of surface lithium into lithium diffusion transport behavior along the lithium-philic skeleton. The porous lithium-philic skeleton is used as a pre-lithium storage matrix, can limit the infinite volume expansion of lithium, can homogenize lithium ion flow, reduces the effective current density on the surface, constructs a stable surface Solid Electrolyte Interface (SEI) with fast ion transmission characteristics, and further inhibits the growth of lithium dendrites. Further increases in current density and lithium plating capacity raise further safety concerns. When lithium metal is matched with the solid electrolyte, the safety problem can be solved, and the specific energy of a battery system can be improved. The aim of the invention is realized by the following technical scheme: in a first aspect, the present invention provides a method for preparing a lithium-philic porous interface functional layer, comprising the steps of: S1, dissolving a binder in a nonpolar solvent to form a solution A; S2, adding the lithium-philic porous framework material and the electronic conductor into the solution A through a water bath synthesis method, and stirring and reacting to form a solution B; S3, adding a small amount of ionic conductor into the solution B for many times to form a solution C; And S4, coating the solution C on a current collector, and drying to form a lithium-philic porous interface functional layer on the current collector. As some embodiments of the present invention, in step S1, the binder is selected from at least one of styrene-Butadiene Rubber (BR), polypropylene carbonate (PPC), polyisobutylene (PIB), polyvinylidene fluoride (PVDF). The binder has good flexibility to buffer the volume change of the active material during charge and discharge, does not react with the high-activity solid electrolyte (especially sulfide electrolyte), has certain lithium ion conduction capacity to optimize