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CN-122025521-A - Preparation method of high-performance layered dry electrode and application of high-performance layered dry electrode in lithium metal battery

CN122025521ACN 122025521 ACN122025521 ACN 122025521ACN-122025521-A

Abstract

The invention discloses a preparation method of a high-performance layered dry electrode and application of the high-performance layered dry electrode in a lithium metal battery, wherein the method comprises the following steps of 1, mixing and grinding a monocrystal nickel-based oxide positive electrode material, vapor grown carbon fibers and polytetrafluoroethylene to obtain a dry electrode film I; step 2, mixing and grinding a monocrystalline nickel-based oxide positive electrode material, a polycrystalline nickel-based oxide positive electrode material, vapor grown carbon fibers and polytetrafluoroethylene to obtain a dry electrode film II, step 3, mixing and grinding the polycrystalline nickel-based oxide positive electrode material, the vapor grown carbon fibers and the polytetrafluoroethylene to obtain a dry electrode film III, and step 4, sequentially laminating and combining the dry electrode films I, II and III, and laminating and hot rolling the dry electrode film III and a current collector to obtain the layered dry electrode. The invention improves the electrochemical performance of the dry electrode and promotes the application of the dry electrode in the high-voltage lithium metal battery by carrying out layered design on the dry electrode.

Inventors

  • CHENG XINQUN
  • LIU ZHICHENG
  • MA XING
  • ZUO PENGJIAN
  • DU CHUNYU

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260512
Application Date
20260305

Claims (10)

  1. 1. The preparation method of the high-performance layered dry electrode is characterized by comprising the following steps of: Step 1, mixing a monocrystalline nickel-based oxide positive electrode material, vapor grown carbon fiber and polytetrafluoroethylene in a mass ratio of 0.87-0.90:0.05-0.1:0.03-0.05 in a mixing device, pouring the obtained dry electrode powder into a mortar for grinding, and primarily forming a film to obtain a dry electrode film I; Step 2, mixing the monocrystalline nickel-based oxide positive electrode material, the polycrystalline nickel-based oxide positive electrode material, the vapor grown carbon fiber and the polytetrafluoroethylene in a mass ratio of 0.45-0.46:0.45-0.46:0.04-0.08:0.02-0.04 in a mixing device, pouring the obtained dry electrode powder into a mortar for grinding, and primarily forming a film to obtain a dry electrode film II; Step 3, completing mixing of the polycrystalline nickel-based oxide positive electrode material, vapor grown carbon fiber and polytetrafluoroethylene in a mass ratio of 0.8-0.85:0.12-0.15:0.03-0.05 in mixing equipment, pouring the obtained dry electrode powder into a mortar for grinding, and primarily forming a film to obtain a dry electrode film III; and 4, sequentially laminating and combining the dry electrode film I, the dry electrode film II and the dry electrode film III, gradually thinning the dry electrode film after lamination and combination to 75-100 mu m under a roller press, and finally attaching the dry electrode film III to a current collector, and hot rolling to obtain the layered dry electrode.
  2. 2. The method for preparing a high-performance layered dry electrode according to claim 1, wherein the mixing equipment is a ball mill or a powder mill.
  3. 3. The method for preparing the high-performance layered dry electrode according to claim 1, wherein the rotating speed of the mixing is 180-200 r/min, and the ball milling time is 100-120 min.
  4. 4. The method for preparing a high-performance layered dry electrode according to claim 1, wherein the grinding time is 10-30 min.
  5. 5. The method for preparing the high-performance layered dry electrode according to claim 1, wherein the single crystal nickel-based oxide positive electrode material is a single crystal nickel lithium manganate or single crystal nickel cobalt manganese ternary electrode material.
  6. 6. The method for preparing a high-performance layered dry electrode according to claim 5, wherein the single-crystal nickel-cobalt-manganese ternary electrode material is LiNi 0.8 Mn 0.1 Co 0.1 O 2 or LiNi 0.9 Mn 0.05 Co 0.05 O 2 .
  7. 7. The method for preparing the high-performance layered dry electrode according to claim 1, wherein the polycrystalline nickel-based oxide positive electrode material is a polycrystalline lithium nickel manganese oxide or polycrystalline nickel cobalt manganese ternary electrode material.
  8. 8. The method for preparing a high-performance layered dry electrode according to claim 7, wherein the polycrystalline nickel-cobalt-manganese ternary electrode material is LiNi 0.8 Mn 0.1 Co 0.1 O 2 or LiNi 0.9 Mn 0.05 Co 0.05 O 2 .
  9. 9. The method for preparing a high-performance layered dry electrode according to claim 1, wherein the temperature of the hot rolling is 100-120 ℃.
  10. 10. Use of a layered dry electrode prepared according to the method of any one of claims 1-9 in a lithium metal battery.

Description

Preparation method of high-performance layered dry electrode and application of high-performance layered dry electrode in lithium metal battery Technical Field The invention belongs to the field of energy storage materials, relates to a preparation method of a dry electrode, and in particular relates to a preparation method of a high-performance layered dry electrode and application of the high-performance layered dry electrode in a lithium metal battery. Background Since 1991, lithium ion batteries have been widely used in the fields of portable electronic devices, electric vehicles, energy storage devices, and the like in order to meet various demands of social production. Today, the world is currently moving rapidly towards "new energy + environmental" at low cost. In contrast, the use of a large amount of N-methyl-2-pyrrolidone (NMP) in the conventional wet process not only increases the material cost, but also results in a large amount of energy consumption (for NMP removal) which accounts for 82% of the total energy consumption for electrode preparation. More importantly, the high toxicity and flammability of NMP causes serious health and safety problems that hinder the environmental friendliness and sustainability of the current battery industry. In contrast, the dry process does not use NMP solvent to prepare slurry, avoids the solvent evaporation drying process, and has remarkable advantages in energy consumption and processing cost. To date, lithium iron phosphate (LiFePO 4), lithium cobalt oxide (LiCoO 2), and lithium nickel cobalt manganese oxide anodes have been prepared based on dry process methods. However, for lithium nickel manganese oxide (LiNi 0.5Mn1.5O4, abbreviated as LNMO) anodes at high cut-off voltages, particularly for thick electrodes under rapid charge/discharge conditions required for practical applications, the available specific capacity and rate performance of the LNMO anode are degraded due to slow electron and ion transport caused by the thickness of the high-load anode itself. In addition, the positive electrode electrolyte intermediate phase (CEI) layer formed on the dry LNMO positive electrode cannot completely suppress the continuous parasitic reaction between the LNMO and the electrolyte, resulting in serious capacity fade during cycling. Together, these factors prevent the pursuit of high energy densities by conventional dry methods. Therefore, it is highly desirable to develop dry LMNO anodes with overall high energy density, rate capability, and area capacity to fully accommodate practical battery production and applications. Disclosure of Invention Aiming at the defects of dry technology and commercial electrolyte, the invention provides a preparation method of a high-performance layered dry electrode and application of the high-performance layered dry electrode in a lithium metal battery. According to the invention, by carrying out three-layer layered design on the dry electrode, an excellent high-voltage-resistant electrode interface is constructed at the electrode-electrolyte interface, and the electrode electron and lithium ion conduction rate is improved at the side close to the current collector, so that the electrochemical performance of the dry electrode is further improved, and the application of the dry electrode in a high-voltage lithium metal battery is further promoted. The invention aims at realizing the following technical scheme: a preparation method of a high-performance layered dry electrode comprises the following steps: Step 1, mixing a monocrystalline nickel-based oxide positive electrode material, vapor grown carbon fiber and polytetrafluoroethylene in a mass ratio of 0.87-0.90:0.05-0.1:0.03-0.05 in a mixing device, pouring the obtained dry electrode powder into a mortar for grinding, and primarily forming a film to obtain a dry electrode film I; Step 2, mixing the monocrystalline nickel-based oxide positive electrode material, the polycrystalline nickel-based oxide positive electrode material, the vapor grown carbon fiber and the polytetrafluoroethylene in a mass ratio of 0.45-0.46:0.45-0.46:0.04-0.08:0.02-0.04 in a mixing device, pouring the obtained dry electrode powder into a mortar for grinding, and primarily forming a film to obtain a dry electrode film II; Step 3, completing mixing of the polycrystalline nickel-based oxide positive electrode material, vapor grown carbon fiber and polytetrafluoroethylene in a mass ratio of 0.8-0.85:0.12-0.15:0.03-0.05 in mixing equipment, pouring the obtained dry electrode powder into a mortar for grinding, and primarily forming a film to obtain a dry electrode film III; and 4, sequentially laminating and combining the dry electrode film I, the dry electrode film II and the dry electrode film III, gradually thinning the dry electrode film after lamination and combination to 75-100 mu m under a roller press, and finally attaching the dry electrode film III to a current collector, and hot rolling to obtain