Search

CN-122000617-A - Lithium battery material and preparation method and application thereof

CN122000617ACN 122000617 ACN122000617 ACN 122000617ACN-122000617-A

Abstract

The invention provides a lithium battery material, a preparation method and application thereof, wherein the lithium battery material comprises a polymer and lithium nitrate, the polymer contains polar groups, and the mass of the lithium nitrate is 1-30wt% of the mass of the polymer. The lithium battery material provided by the invention well solves the problem of poor dissolution when the lithium nitrate is applied to a lithium battery, and when the material is applied to the lithium battery, a 'lithium nitrate library' is introduced into a battery system, so that the lithium nitrate and nitrate can be slowly released in the circulation process, and the electrical property of the lithium battery is well improved.

Inventors

  • CAO PENGFEI
  • SONG ZHAOWEI
  • SHAN XINYUAN
  • SUN HAIBO

Assignees

  • 北京化工大学

Dates

Publication Date
20260508
Application Date
20241104

Claims (10)

  1. 1. A lithium battery material comprises a polymer and lithium nitrate, wherein the polymer contains polar groups, and the mass of the lithium nitrate is 1-30wt% of the mass of the polymer.
  2. 2. The lithium battery material according to claim 1, wherein the mass of the lithium nitrate is 1 to 20wt% of the mass of the polymer.
  3. 3. The lithium battery material according to claim 1, wherein the polymer is one selected from a cross-linked polar polymer and a polar group-modified polymer.
  4. 4. The lithium battery material of claim 1, wherein the polar group is selected from one or a combination of ether groups, ester groups, amide groups, fluoroether groups, sulfonic acid groups, and fluoroester groups.
  5. 5. The preparation method of the lithium battery material according to any one of claims 1 to 4, comprising the following steps: Under the protection of inert gas, dissolving a polymerization monomer in a solvent, performing polymerization reaction under the initiation of an initiator, and adding a cross-linking agent to continue the reaction after a period of reaction to obtain a polymer; and step two, mixing the polymer and lithium nitrate, and dissolving to obtain the lithium battery material.
  6. 6. The method according to claim 5, wherein the polymer monomer is selected from the group consisting of organic monomers having a double bond, preferably at least two of ethylene carbonate, polyethylene glycol methacrylate, polyethylene glycol methyl ether methacrylate, ethylene glycol monoethyl ether acrylate, methoxypolyethylene glycol acrylate, (4-styrenesulfonyl) (trifluoromethanesulfonyl) imide lithium, styrenesulfonate lithium, perfluoroalkyl vinyl ether, perfluorooctyl acrylate, hexafluoropropylene, and vinylidene fluoride.
  7. 7. The method for preparing a lithium battery material according to claim 5, wherein the initiator is one or a combination of azobisisobutyronitrile, dibenzoyl peroxide and dicumyl peroxide.
  8. 8. The method of producing a lithium battery material according to claim 5, wherein the crosslinking agent is selected from isocyanate compounds, preferably one or a combination of polyhexamethylene isocyanate, hexamethylene isocyanate, 4-diphenylmethane diisocyanate.
  9. 9. The use of the lithium battery material according to any one of claims 1 to 4 for modifying a separator for a lithium battery.
  10. 10. The use of the lithium battery material according to claim 9, wherein the method for modifying the separator with the lithium battery material comprises the steps of: loading the lithium battery material onto a substrate in an inert gas atmosphere, heating and drying in a vacuum state to obtain a modified diaphragm; preferably, the substrate material can be one of glass fiber, lithium battery diaphragm, ceramic modified diaphragm, electrostatic spinning material and non-woven fabric; preferably, the load of lithium nitrate on the diaphragm is 0.1-1% of the mass of the diaphragm, and the load of the polymer on the diaphragm is 10-40% of the mass of the diaphragm.

Description

Lithium battery material and preparation method and application thereof Technical Field The invention relates to the technical field of lithium batteries, in particular to a lithium battery material and a preparation method and application thereof. Background Due to the increasingly prominent problem of environmental pollution of traditional energy, under the support of high-demand market stimulation and national policy, the share of new energy industry in the energy field is rising year by year, and the energy density and the safety stability of batteries in the fields of transportation, energy storage and electronic digital codes are more required. Lithium ion secondary batteries are widely used by virtue of their high energy density, high cycle stability and long cycle life. When the lithium salt is dissolved into the solvent, a lithium ion-solvent complex is formed. In general, solvent reduction of metallic Li forms organic-inorganic components, while reduction of inorganic anions forms only inorganic components. Lithium nitrate (LiNO 3) has higher reducing power than LiPF 6, liFSI and LiTFSI, and can participate in the sheath of Li solvent, and an inorganic solid electrolyte interface layer (SEI) is formed on the Li metal anode, so that the growth of lithium dendrite is inhibited, and the cycle stability is improved. In addition, nitrate anions (NO 3-) have lower activation energy than other types of anions, which will preferentially adsorb in the helmholtz inner plane, can first be reduced to form inorganic SEI components such as Li 2O、LiNxOy and Li 3 N, and can improve the stiffness and ionic conductivity of the electrode interface. However, lithium nitrate has the problem of poor dissolution in most electrolyte systems, such as carbonate solvents and partial ether solvents, which greatly limits the wide application of lithium nitrate. Although there are various methods for improving the compatibility of lithium nitrate in solvents, such as the addition of high-solubility solvents such as methyl sulfoxide and gamma-butyrolactone, these solutions can also react with lithium negative electrodes to form SEI based on organic components, which is detrimental to the stability of the negative electrode side. In addition, the dissolution of lithium nitrate can be realized by the aid of the inorganic salt CuF 2, and the influence of a cosolvent on SEI can be avoided, but the application range is narrow, and the method is only suitable for a plurality of solvent systems. Therefore, it is a highly desirable problem to find a solution for introducing lithium nitrate into a battery system that is efficient, versatile, and simple to use, so as to meet the market demand for high-performance and high-stability lithium secondary batteries. Disclosure of Invention In order to solve the problems, the invention provides a lithium battery material and a preparation method thereof, wherein the material comprises a polymer dissolved with lithium nitrate, the polymer contains polar groups, the polar groups can be dissociated to dissolve the lithium nitrate, the problem of poor dissolution when the lithium nitrate is applied to a lithium battery is well solved, when the material is applied to the lithium battery, a 'lithium nitrate library' is introduced into a battery system, the lithium nitrate and nitrate can be slowly released in the circulation process, and the electrical property of the lithium battery is well improved. First, it is an object of the present invention to provide a lithium battery material. Specifically, the lithium battery material comprises a polymer and lithium nitrate, wherein the polymer contains polar groups and can dissolve the lithium nitrate, and the mass of the lithium nitrate is 1-30wt%, preferably 1-20wt%, of the mass of the polymer. According to the invention, the polymer is used as a medium to dissolve lithium nitrate into the diaphragm, so that the lithium nitrate is slowly released in the battery circulation process, and the stability of the lithium battery is ensured. Further, the polymer is selected from one of a cross-linked polar polymer and a polar group modified polymer. Further, the polar group in the polymer is selected from one or a combination of ether group (-O-), ester group (-COO-), amide group (-CONH-), fluoroether group (-O-CF 2-CF2 -), sulfonic acid group (-SO 3 H) and fluoroester group (-COO-CF 2-CF2 -). When the polymer and lithium nitrate are mixed, the lithium nitrate is stably dissolved in a polymer network, and polar groups contained in the polymer have better dissociation effect on the lithium nitrate, so that the lithium nitrate plays a role in a battery system. Next, another object of the present invention is to provide a method for preparing the lithium battery material according to one of the objects of the present invention. Specifically, the method comprises the steps of: Under the protection of inert gas, dissolving a polymerization monomer in a solvent, perf