Double-Layer Lithium Anode Protection Against Dendrite Growth

Solution Overview

Problem

Lithium metal batteries, such as lithium-sulfur batteries, face rapid degradation due to lithium dendrite growth and side reactions with electrolytes, which are not effectively inhibited by existing polymer protective films with low strength and high ion conductivity.

Innovation Solution

A negative electrode for lithium secondary batteries is designed with a double-layer protective system, where the first protective layer has high ion conductivity and electrolyte uptake, and the second layer has low ion conductivity and high strength, preventing dendrite growth and side reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a polymer protective film with high ion conductivity and electrolyte uptake is used, then ion transport is improved, but the film strength is insufficient and dendrite growth cannot be suppressed

Engineering Contradiction:

Improveion conductivityVSAvoidfilm strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The protective film is divided into two distinct layers: a first protective film with high ion conductivity and electrolyte uptake properties, and a second protective film with high strength properties. This segmentation allows each layer to perform its specialized function without compromise - the first layer facilitates ion transport while the second layer provides mechanical strength to suppress dendrite growth.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the protective film structure are assigned different properties tailored to local requirements. The first protective film (closer to the lithium metal) has high ion conductivity and electrolyte uptake to facilitate ion transport, while the second protective film (outer layer) has high strength to provide mechanical support and suppress dendrite penetration.

Inventive Principle:

Principle #3Local quality

2Strength

If a protective film with high strength is used to suppress dendrite, then dendrite growth is inhibited, but ion conductivity and electrolyte uptake are reduced

Engineering Contradiction:

Improvefilm strengthVSAvoidion conductivity

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The protective film is divided into two distinct layers: a first protective film with high ion conductivity and electrolyte uptake properties, and a second protective film with high strength properties. This segmentation allows each layer to perform its specialized function without compromise - the first layer facilitates ion transport while the second layer provides mechanical strength to suppress dendrite growth.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If a single-layer protective film is used, then device complexity is reduced, but it cannot simultaneously provide both high strength and high ion conductivity

Engineering Contradiction:

Improveprotective film structureVSAvoiddual functionality

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The protective film is divided into two distinct layers: a first protective film with high ion conductivity and electrolyte uptake properties, and a second protective film with high strength properties. This segmentation allows each layer to perform its specialized function without compromise - the first layer facilitates ion transport while the second layer provides mechanical strength to suppress dendrite growth.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protective film system combines two different polymer materials with complementary properties into a composite structure. The first protective film uses polymers with high ion conductivity and electrolyte uptake, while the second protective film uses polymers with high strength. This composite approach enables the overall system to exhibit both high ion conductivity and high strength, achieving dual functionality that neither material could provide alone.

Inventive Principle:

Principle #40Composite materials

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 double-layer protective system effectively controls lithium dendrite growth and suppresses side reactions, enhancing coulombic efficiency and discharging capacity of lithium secondary batteries.

Implementation Method 1

the first protective layer has high ion conductivity and electrolyte uptake

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS11923538B2Negative electrode for lithium secondary battery and lithium secondary battery comprising same

Publication Date: 2024.03.05 LG ENERGY SOLUTION LTD

AI summary

A negative electrode for a lithium secondary battery including a lithium metal layer; a first protective layer formed on a surface of the lithium metal layer; and a second protective layer formed on a surface of the first protective layer opposite the lithium metal layer, wherein the first protective layer and the second protective layer are different from each other in at least one property selected from the group consisting of ion conductivity and electrolyte uptake.