Dual-Layer Negative Electrode Structure for Fast-Charging Adhesion

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Solution Overview

Problem

Rechargeable lithium batteries face challenges in achieving high adhesion of the active material layer to the current collector and fast charging performance.

Innovation Solution

A negative electrode design with a first and second negative electrode active material layer sequentially arranged on the current collector, where the layers have specific inclination angles and porosities that satisfy certain criteria, enhancing adhesion and fast-charging capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-layer negative electrode active material layer is used, then the structure is simple, but the adhesion to current collector and fast-charging performance are insufficient

Engineering Contradiction:
Improveadhesion to current collectorVSAvoidstructure of negative electrode
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The negative electrode active material layer is divided into two distinct layers: a first negative electrode active material layer in contact with the current collector, and a second negative electrode active material layer on top of the first layer. This segmentation allows each layer to be optimized for specific functions, improving overall adhesion and fast-charging performance while managing structural complexity.

Inventive Principle:
Principle #1Segmentation

2Strength

If the active material layer is designed for high adhesion, then bonding strength increases, but fast-charging capability may be compromised

Engineering Contradiction:
Improveadhesion strengthVSAvoidfast-charging rate
Core Design Contradiction:
StrengthVSSpeed

Solution Approach 1:

Different regions of the negative electrode are assigned different properties: the first layer (near current collector) is optimized for adhesion with higher bonding strength, while the second layer (outer layer) is optimized for fast-charging performance with appropriate porosity and active material composition. This local differentiation allows simultaneous optimization of adhesion strength and fast-charging rate without compromise.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design provides high adhesion to the current collector and enables fast charging, improving battery performance and characteristics.

Implementation Method 1

an active material that is capable of intercalating and deintercalating lithium ions

Methodology Applied
Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

Electrical energy is generated by oxidation and reduction reactions when lithium ions are intercalated/deintercalated into/from the positive electrode and the negative electrode

Methodology Applied
Scientific EffectOxidation and reduction reactions: Redox Reactions

Data Source

PatentEP4700847A1Negative electrode for rechargeable lithium battery and rechargeable lithium battery including the same
Publication Date: 2026.02.25 SAMSUNG SDI CO LTD
  • EP4700847A1 patent drawingFigure 1~2
  • EP4700847A1 patent drawingFigure 3A~3B
  • EP4700847A1 patent drawingFigure 4A~4B

AI summary

A negative electrode for a rechargeable lithium battery includes a current collector and a negative electrode active material layer formed on at least one surface of the current collector, wherein the negative electrode active material layer includes a first negative electrode active material layer and a second negative electrode active material layer, which are sequentially arranged on the current collector, and satisfies Expression 1: Averageinclinationangleoffirstnegativeelectrodeactivemateriallayer<Averageinclinationangleofsecondnegativeelectrodeactivemateriallayer. Also disclosed is a rechargeable lithium battery including the negative electrode.