Copper-Magnesium Intermetallic Interface for Lithium Alloy Anodes

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Solution Overview

Problem

The use of a negative electrode with a lithium alloy layer in lithium secondary batteries results in a decrease in cycle characteristics due to poor adhesion between the lithium alloy layer and the current collector, leading to deterioration in battery performance.

Innovation Solution

Incorporating a copper-magnesium intermetallic compound at the interface between the copper current collector and the magnesium-containing lithium alloy layer to enhance adhesion and improve cycle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a lithium alloy layer is used as the negative electrode active material, then the theoretical capacity density is improved, but the cycle characteristics deteriorate due to poor adhesion between the lithium alloy layer and the current collector

Engineering Contradiction:

Improvetheoretical capacity densityVSAvoidcycle characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A copper-magnesium intermetallic compound layer is introduced as an intermediary between the copper current collector and the lithium alloy layer. This intermetallic compound layer serves as a mediator that enhances the adhesion between the lithium alloy layer and the current collector, thereby improving cycle characteristics while maintaining high theoretical capacity density.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The negative electrode is constructed as a composite structure consisting of a copper current collector, a copper-magnesium intermetallic compound layer, and a lithium alloy layer. This composite material structure combines the advantages of each component: the copper current collector provides electrical conductivity, the intermetallic compound layer provides strong adhesion, and the lithium alloy layer provides high capacity density.

Inventive Principle:

Principle #40Composite materials

2Strength

If a copper-magnesium intermetallic compound is introduced at the interface, then the adhesion between the lithium alloy layer and the current collector is improved, but the device complexity increases

Engineering Contradiction:

Improveadhesion between lithium alloy layer and current collectorVSAvoidstructure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The copper-magnesium intermetallic compound is not introduced throughout the entire negative electrode structure, but only at the critical interface region between the current collector and the lithium alloy layer. This local application of the intermetallic compound provides the necessary adhesion strength only where needed, minimizing the increase in overall device complexity while effectively solving the adhesion problem.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP4704172A1Negative electrode for lithium secondary battery, and lithium secondary battery

Publication Date: 2026.03.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

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AI summary

The disclosed negative electrode (12) for a lithium secondary battery includes a current collector (12a) containing copper and an Mg-containing lithium alloy layer (12b) disposed on the current collector (12a). An intermetallic compound of copper and magnesium is present at the interface between the current collector (12a) and the Mg-containing lithium alloy layer (12b).