Layered Lithium Secondary Battery for Dendrite Suppression

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Solution Overview

Problem

Lithium secondary batteries face challenges with lithium metal deposition in a dendrite form, leading to increased specific surface area and side reactions, which deteriorate discharge capacity and cycle characteristics.

Innovation Solution

A lithium secondary battery design featuring a negative electrode with multiple layers, including a first layer for storing lithium ions, a second layer for lithium metal deposition, and a third layer with insulation and lithium ion permeability, to suppress lithium metal deposition between the third layer and the separator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal is used as negative electrode active material to achieve high capacity, then battery capacity increases, but lithium metal deposits in dendrite form causing cycle characteristics to deteriorate

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The negative electrode is divided into multiple functional layers: a first layer containing lithium ion storage material (graphite or alloy), a second layer containing lithium metal, and a third layer containing insulating material with lithium ion permeability. This segmentation prevents dendrite formation by controlling lithium deposition in the second layer while the third layer blocks further dendrite growth toward the separator.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The third layer containing insulating material acts as an intermediary between the lithium metal layer and the separator. This intermediate layer permits lithium ion transport but prevents direct contact between deposited lithium metal and the separator, thereby blocking dendrite penetration while maintaining ionic conductivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If lithium metal deposits on negative electrode during charging, then high capacity is achieved, but specific surface area increases and side reactions increase

Engineering Contradiction:

Improvelithium metal depositionVSAvoidside reactions

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

Different regions of the negative electrode are assigned different functions: the first layer provides stable lithium ion storage, the second layer allows controlled lithium metal deposition with high capacity, and the third layer provides selective permeability. This local differentiation enables high lithium deposition while controlling the environment to minimize harmful side reactions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The third layer contains insulating material with lithium ion permeability, creating a porous or selectively permeable structure that allows lithium ions to pass through while blocking dendrite growth. This porous structure maintains ionic conductivity while preventing direct contact between lithium metal and the separator, reducing side reactions.

Inventive Principle:

Principle #31Porous materials

3Quantity of substance

If dendrite is generated on negative electrode, then capacity increases, but discharge capacity deteriorates

Engineering Contradiction:

Improvelithium metal amountVSAvoiddischarge capacity

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The third layer with insulating material and lithium ion permeability is pre-installed between the lithium metal layer and the separator before dendrite formation occurs. This preliminary protective structure prevents dendrite penetration during subsequent charging cycles, ensuring that deposited lithium metal remains electrically connected and functional for discharge.

Inventive Principle:

Principle #10Preliminary action

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

This design improves cycle characteristics by stabilizing lithium metal deposition and preventing dendrite growth, enhancing the battery's capacity retention and performance.

Implementation Method 1

the first layer contains a material capable of storing lithium ions

Methodology Applied

Scientific EffectIntercalation: Adsorption

Implementation Method 2

the third layer has an insulation property and a lithium ion permeability

Methodology Applied

Scientific EffectIon permeability: Permeation

Data Source

PatentUS12412887B2Lithium secondary battery

Publication Date: 2025.09.09 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A lithium secondary battery includes a positive electrode, a negative electrode, a lithium ion conductive nonaqueous electrolyte, and a separator disposed between the positive electrode and the negative electrode. On the negative electrode, lithium metal deposits during charging, and the lithium metal is dissolved during discharging; the negative electrode includes a negative electrode current collector, and a plurality of layers stacked on the negative electrode current collector; the plurality of layers include a first layer, a second layer, and a third layer; of the first to third layers, the first layer is closest to the negative electrode current collector, and the third layer is farthest from the negative electrode current collector; the first layer contains a material capable of storing lithium ions; the second layer contains lithium metal, and the third layer has an insulation property and a lithium ion permeability.