WO-2026091671-A1 - NEGATIVE ELECTRODE SHEET AND PREPARATION METHOD THEREFOR, AND LITHIUM BATTERY

WO2026091671A1WO 2026091671 A1WO2026091671 A1WO 2026091671A1WO-2026091671-A1

Abstract

The present disclosure relates to the technical field of lithium batteries. Disclosed are a negative electrode sheet and a preparation method therefor, and a lithium battery. The negative electrode sheet comprises a current collector and an active layer arranged on the surface of the current collector. The components of the active layer comprise a negative electrode active material, a conductive agent, a binder, and an additive. The additive is a metal oxide having an inverse opal structure. The metal oxide having an inverse opal structure is added to the active layer of the negative electrode sheet, and the metal oxide can impart a special pore structure to the negative electrode sheet, thereby improving the porosity of the negative electrode sheet, improving the wettability of an electrolyte to the negative electrode sheet, and improving the liquid retention amount of the negative electrode sheet.

Inventors

BAO, Ruiqi
FAN, Xiaoqiao
LIU, YANG
HUANG, Haining

Assignees

上海兰钧新能源科技有限公司

Dates

Publication Date: 20260507
Application Date: 20250710
Priority Date: 20241101

Claims (15)

A negative electrode sheet, characterized in that it comprises a current collector and an active layer disposed on the surface of the current collector; The active layer comprises negative electrode active material, conductive agent, binder and additives; The additive is a metal oxide with an inverse opal structure.
The negative electrode sheet according to claim 1, wherein the active layer has a multilayer structure; Along the direction away from the current collector, the additive content in each layer of the active layer of the multilayer structure gradually increases.
According to claim 2, the negative electrode sheet is characterized in that the content of the additive in each layer of the multilayer structure of the active layer satisfies the following formula: The active layer is defined as the layer closest to the current collector as the first layer, a1 is the percentage of the additive in the first layer in the total mass of the active layer, an is the percentage of the additive in the nth layer in the total mass of the active layer, n is the current layer number, ntotal is the total number of active layers, ntotal ≥ 2, and p is the percentage of the additive in the total mass of the active layer, 0.1% ≤ p ≤ 50%. When n_total ≥ 2, 0 ≤ a_1 < p/ n_total , a_n starts from the current collector side and gradually increases towards the outermost layer.
The negative electrode sheet according to any one of claims 1 to 3, characterized in that the metal oxide satisfies: The D50 of the metal oxide is 1–40 μm; and/or, The internal pore size of the metal oxide particles is 0.05 to 20 μm, and the internal pore volume accounts for 50 to 90% of the particle volume.
According to claim 4, the negative electrode is characterized in that the metal oxide is selected from at least one of titanium dioxide, tin dioxide and germanium dioxide.
The negative electrode sheet according to any one of claims 1 to 5 is characterized in that the active layer comprises, by mass percentage, 43-97.9% of the negative electrode active material, 0.5-3% of the conductive agent, 1-2.5% of the binder, and 0.1-50% of the additives.
The negative electrode sheet according to any one of claims 1 to 6 is characterized in that the coating surface density of the active layer is 40 to 400 g/ m² .
According to claim 6, the negative electrode sheet is characterized in that the active layer comprises, by mass percentage, 0.5-1.5% of a dispersant.
According to claim 8, the negative electrode sheet is characterized in that the dispersant is selected from at least one of sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, and sodium carboxyethyl cellulose.
The negative electrode sheet according to any one of claims 1 to 9 is characterized in that the conductive agent is selected from at least one of carbon black, graphite sheet, carbon nanotube and graphene.
The negative electrode sheet according to any one of claims 1 to 10 is characterized in that the adhesive is selected from at least one of styrene-butadiene rubber, sodium polyacrylate, sodium alginate and polyacrylonitrile.
The negative electrode sheet according to any one of claims 1 to 11 is characterized in that the negative electrode active material is selected from at least one of graphite, hard carbon, soft carbon, lithium titanate and mesophase carbon microspheres.
The negative electrode sheet according to any one of claims 1 to 12 is characterized in that the active layer is provided on both opposite sides of the current collector.
A method for preparing a negative electrode sheet, characterized in that the method for preparing the negative electrode sheet as described in any one of claims 1 to 13 includes coating a negative electrode slurry containing various components of the active layer onto the surface of the current collector, followed by drying and cold pressing.
A lithium battery, characterized in that it includes a negative electrode sheet as described in any one of claims 1 to 13.

Description

Negative electrode sheet and its preparation method and lithium battery Cross-reference of related applications This disclosure claims priority to Chinese Patent Application No. 2024115503702, filed on November 1, 2024, entitled “Negative Electrode Sheet and Preparation Method Thereof and Lithium Battery”, the entire contents of which are incorporated herein by reference. Technical Field This disclosure relates to the field of lithium battery technology, and more specifically, to negative electrode sheets, their preparation methods, and lithium batteries. Background Technology Lithium-ion rechargeable battery technology is developing rapidly and its applications are becoming increasingly widespread. Currently, the market demands higher performance from lithium-ion batteries, requiring them to achieve both high energy density and high rate capability. For conventional graphite and silicon anode lithium-ion batteries, increasing the coating amount and compaction density of the electrode to improve energy density can lead to a significant increase in electrode tortuosity due to the solid, non-porous structure of these materials. This reduces electrolyte wetting and ion transport rate, resulting in decreased rate performance and a loss of battery power. To simultaneously achieve high energy density and high rate capability in lithium-ion batteries, it is essential to increase the specific surface area of the anode material, improve the porosity of the anode electrode, and optimize the microporous structure of the electrode, thereby enhancing energy density while maintaining the lithium-ion transport rate. Currently, the main ways to improve the porosity of the negative electrode sheet and enhance electrolyte wettability include adding pore-forming agents and laser drilling. However, adding pore-forming agents has limitations because these agents do not have lithium storage capacity, and their residue can increase the proportion of impurities, affecting the performance and energy density of lithium batteries. Laser drilling is costly and involves additional drilling steps. In view of this, this disclosure is hereby made. Summary of the Invention The purpose of this disclosure is to provide a negative electrode sheet, a method for preparing the same, and a lithium battery. This disclosure is implemented as follows: In a first aspect, this disclosure provides a negative electrode sheet, including a current collector and an active layer disposed on the surface of the current collector; The active layer consists of negative electrode active material, conductive agent, binder and additives; The additive is a metal oxide with an inverse opal structure. In an optional implementation, the active layer has a multilayer structure; Along the direction away from the current collector, the additive content of each layer in the multilayer active layer gradually increases. In an optional embodiment, the additive content of each layer in the multilayer structure of the active layer satisfies the following formula: The active layer is defined as the layer closest to the current collector, where a1 is the percentage of the additive in the first layer, an is the percentage of the additive in the nth layer, n is the current layer number, ntotal is the total number of active layers ( ntotal ≥ 2), and p is the percentage of the additive in the entire active layer (0.1% ≤ p ≤ 50%). When n_total ≥ 2, 0 ≤ a_1 < p/ n_total , a_n starts from the current collector side and gradually increases towards the outermost layer. In an optional implementation, the metal oxide satisfies: The D50 of the metal oxide is 1–40 μm; and/or the internal pore size of the metal oxide particles is 0.05–20 μm, and the internal pore volume accounts for 50–90% of the particle volume. In an optional embodiment, the metal oxide is selected from at least one of titanium dioxide, tin dioxide, and germanium dioxide. In an optional embodiment, the active layer comprises, by mass percentage, 43-97.9% negative electrode active material, 0.5-3% conductive agent, 1-2.5% binder, and 0.1-50% additives. In an optional embodiment, the active layer further comprises 0.5 to 1.5% dispersant by mass percentage; The dispersant is selected from at least one of sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, and sodium carboxyethyl cellulose. In an optional implementation, at least one of the following features (1)-(4) is also included: (1) The conductive agent is selected from at least one of carbon black, graphite sheets, carbon nanotubes and graphene; (2) The adhesive is selected from at least one of styrene-butadiene rubber, sodium polyacrylate, sodium alginate and polyacrylonitrile; (3) The negative electrode active material is selected from at least one of graphite, hard carbon, soft carbon, lithium titanate and mesophase carbon microspheres; (4) An active layer is provided on both opposite sides of the current collector. Secondly, this disclosure provides a m