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CN-122025544-A - Negative electrode plate of sodium ion battery and sodium ion battery

CN122025544ACN 122025544 ACN122025544 ACN 122025544ACN-122025544-A

Abstract

The application provides a negative electrode plate of a sodium ion battery and the sodium ion battery, and relates to the field of sodium ion batteries. The negative electrode plate comprises a base material, a first hard carbon layer and a second hard carbon layer, wherein the first hard carbon layer is arranged between the base material and the second hard carbon layer, and the negative electrode plate independently comprises 80% -97% of hard carbon particles, 1% -8% of conductive agent, 1% -6% of binder and 1% -6% of dispersing agent, wherein the particle size of the hard carbon particles in the first hard carbon layer is larger than that of the hard carbon particles in the second hard carbon layer, and the layer spacing of the hard carbon particles in the first hard carbon layer is smaller than that of the hard carbon particles in the second hard carbon layer, calculated by 100% of the total mass of the raw materials of the first hard carbon layer and the second hard carbon layer. The structural design realizes the differential transmission and storage of sodium ions in different active layers, thereby synergistically optimizing the energy density, the multiplying power performance and the cycling stability of the anode material and comprehensively improving the comprehensive performance of the sodium ion battery.

Inventors

  • CHEN SHEN
  • YANG XIAOMAN
  • XIE YUQIANG
  • LUO XINGHUAI

Assignees

  • 深圳为方能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. The sodium ion battery negative electrode plate is characterized by comprising a base material, a first hard carbon layer and a second hard carbon layer, wherein the first hard carbon layer is arranged between the base material and the second hard carbon layer; The total mass of the raw materials of the first hard carbon layer and the second hard carbon layer is calculated as 100%, and the raw materials independently comprise 80% -97% of hard carbon particles, 1% -8% of conductive agent, 1% -6% of binder and 1% -6% of dispersing agent; the particle size of the hard carbon particles in the first hard carbon layer is larger than that of the hard carbon particles in the second hard carbon layer, and the interlayer spacing of the hard carbon particles in the first hard carbon layer is smaller than that of the hard carbon particles in the second hard carbon layer.
  2. 2. The negative electrode tab of sodium ion battery of claim 1, wherein the substrate comprises copper foil or aluminum foil; And/or the number of the groups of groups, The thickness of the substrate is 3-20 mu m.
  3. 3. The negative electrode tab of sodium ion battery of claim 1, wherein the areal density of the first hard carbon layer and the areal density of the second hard carbon layer are each independently 30-200 g/m 2 .
  4. 4. The sodium ion battery negative electrode tab of claim 1, wherein the hard carbon particles in the first hard carbon layer, the second hard carbon layer each independently comprise at least one of biomass hard carbon, resin hard carbon, coal-based hard carbon, or pitch-based hard carbon.
  5. 5. The negative electrode piece of sodium ion battery according to claim 4, wherein the particle size distribution of the hard carbon particles in the first hard carbon layer is 2.0-3.2 μm in D10, 5.5-7.5 μm in D50 and 10.0-15.0 μm in D90; And/or the number of the groups of groups, The particle size distribution of the hard carbon particles in the second hard carbon layer satisfies that D10 is 1.5-3.0 mu m, D50 is 3.5-5.5 mu m, and D90 is 8.0-12.0 mu m.
  6. 6. The negative electrode piece of sodium ion battery of claim 4, wherein the interlayer spacing d002 of the hard carbon particles in the first hard carbon layer is 0.376-0.382nm; And/or the number of the groups of groups, The interlayer spacing d002 of the hard carbon particles in the second hard carbon layer is 0.383-0.389nm.
  7. 7. The negative electrode tab of sodium ion battery of claim 1, wherein the conductive agent comprises one or more of conductive carbon black, acetylene black, ketjen black, carbon nanotubes, graphene, conductive graphite.
  8. 8. The negative electrode tab of sodium ion battery of claim 1, wherein the binder comprises styrene-butadiene rubber.
  9. 9. The negative electrode tab of sodium ion battery of any one of claims 1-8, wherein the dispersant comprises sodium carboxymethyl cellulose.
  10. 10. A sodium ion battery comprising a negative electrode sheet of the sodium ion battery of any one of claims 1-9.

Description

Negative electrode plate of sodium ion battery and sodium ion battery Technical Field The application relates to the field of sodium ion batteries, in particular to a negative electrode plate of a sodium ion battery and the sodium ion battery. Background The sodium ion battery is used as an electrochemical energy storage device with development potential, and has important practical value in application scenes such as large-scale fixed energy storage facilities, light electric vehicles and the like by virtue of wide distribution of sodium resources, economical efficiency of manufacturing cost and safe reliability of operation process. The negative electrode material is used as a key component in a battery system and has fundamental influence on the energy storage capacity, the charge and discharge speed characteristics, the service life and the environmental adaptability of the battery. The hard carbon material is considered to be the most industrially promising negative electrode material of the sodium ion battery at the present stage by virtue of the comprehensive advantages of moderate preparation cost, convenient and fast raw material acquisition, reasonable sodium ion intercalation potential interval and higher theoretical sodium storage capacity. The sodium storage behavior of the hard carbon material is mainly realized through the reversible intercalation and deintercalation process of sodium ions between graphite-like microcrystalline layers, and the surface adsorption and pore filling mechanisms of the ions in the internal defect area and the micropore structure of the material are accompanied. However, currently mainstream hard carbon negative electrode sheet manufacturing processes generally employ a hard carbon particle system of single particle size specification or simple physical mixing to form an electrode coating with a highly homogeneous microstructure. The homogeneous structure causes the electrode to lack of functional gradient distribution in space dimension, so that the contradiction between high-rate charge-discharge capability and long-term circulation stability cannot be effectively balanced in practical application, and the homogeneous structure is characterized in that under the working condition of high current, the uniformity of an ion transmission path is easy to cause local concentration gradient unbalance, and in the repeated charge-discharge process, the non-uniformity of volume change is easy to induce internal stress concentration and structural damage of the electrode. Although prior studies have explored optimizing hard carbon performance by means of material surface chemical modification or introduction of auxiliary components, the methods are mainly focused on uniformity improvement of overall material properties, and a spatially ordered functional gradient system cannot be established from the macro-structural level of an electrode, so that systematic structural design aiming at performance requirements of different areas is lacking. Therefore, development of a novel negative electrode plate structure is needed, and collaborative optimization of multiple performance parameters can be achieved through gradient layout of space dimension, so that overall electrochemical performance of the sodium ion battery is improved remarkably. In view of the above, there is a need in the art for improvements. Disclosure of Invention The application aims to provide a negative electrode plate of a sodium ion battery and the sodium ion battery so as to solve the problems. In order to achieve the above purpose, the application adopts the following technical scheme: The application provides a sodium ion battery negative electrode plate which comprises a base material, a first hard carbon layer and a second hard carbon layer, wherein the first hard carbon layer is arranged between the base material and the second hard carbon layer; The total mass of the raw materials of the first hard carbon layer and the second hard carbon layer is calculated as 100%, and the raw materials independently comprise 80% -97% of hard carbon particles, 1% -8% of conductive agent, 1% -6% of binder and 1% -6% of dispersing agent; the particle size of the hard carbon particles in the first hard carbon layer is larger than that of the hard carbon particles in the second hard carbon layer, and the interlayer spacing of the hard carbon particles in the first hard carbon layer is smaller than that of the hard carbon particles in the second hard carbon layer. Optionally, the substrate comprises copper foil or aluminum foil; And/or the number of the groups of groups, The thickness of the substrate is 3-20 mu m. Optionally, the areal density of the first hard carbon layer and the areal density of the second hard carbon layer are each independently 30-200 g/m 2. Optionally, the hard carbon particles in the first hard carbon layer, the second hard carbon layer each independently include at least one of biomass hard carbon,