Block Copolymer Electrolyte for Lithium Metal Batteries

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Solution Overview

Problem

Lithium secondary batteries with lithium metal or lithium-containing alloy substrates face instability in contact with liquid electrolytes due to high reactivity, leading to dendrite formation, capacity deterioration, and reduced lifespan, primarily because of the low ion conductivity and mechanical properties at room temperature.

Innovation Solution

A block copolymer electrolyte with a nanoparticle composite is used, comprising structural, ion conductive, rubbery, and hard domains, which improves mechanical properties and ion conductivity, preventing dendrite growth and enhancing electrochemical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a lithium metal or lithium-containing alloy substrate is used as a negative electrode, then high energy density is achieved, but contact stability with liquid electrolyte deteriorates due to high reactivity

Engineering Contradiction:

Improveenergy densityVSAvoidcontact stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A block copolymer electrolyte layer is introduced as an intermediary between the lithium metal substrate and the liquid electrolyte. This intermediate layer prevents direct harmful contact while maintaining ionic conductivity, thus preserving both high energy density and contact stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a composite block copolymer electrolyte consisting of multiple functional domains (ion conductive domain with PEO, structural domain with PMMA, rubbery domain with polyisoprene, and hard domain with polyethylene). This composite structure combines the benefits of different materials to achieve both stability and performance.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If a lithium metal or lithium-containing alloy substrate is used as a negative electrode, then high energy density is achieved, but dendrite formation occurs leading to capacity deterioration

Engineering Contradiction:

Improveenergy densityVSAvoiddendrite formation

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The block copolymer electrolyte acts as a protective intermediary layer that prevents dendrite formation by providing a stable interface between the lithium substrate and liquid electrolyte, thereby eliminating the harmful dendrite generation while maintaining high energy density.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The block copolymer electrolyte provides locally optimized properties at the electrode interface, with specific functional domains positioned to prevent dendrite nucleation and growth while maintaining overall battery performance.

Inventive Principle:

Principle #3Local quality

3Strength

If a block copolymer electrolyte is used to improve mechanical properties, then structural stability is enhanced, but ion conductivity at room temperature deteriorates

Engineering Contradiction:

Improvemechanical propertiesVSAvoidion conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The block copolymer electrolyte is designed as a composite material with distinct functional domains: PEO blocks provide ion conductivity channels, while PMMA, polyisoprene, and polyethylene blocks provide structural support. This composite architecture enables simultaneous achievement of mechanical strength and ion conductivity at room temperature.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the block copolymer electrolyte have specialized local properties: ion conductive domains with high lithium ion mobility for conductivity, and structural domains with rigid chains for mechanical strength. This local differentiation resolves the contradiction between mechanical properties and ion conductivity.

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 electrolyte with a nanoparticle composite in a block copolymer structure provides improved ion conductivity, mechanical strength, and flexibility, leading to increased capacity, extended lifespan, and enhanced rate capability of lithium batteries.

Implementation Method 1

a nanoparticle composite dispersed in the block copolymer

Methodology Applied

Scientific EffectNanocomposite: Nanocomposite

Implementation Method 2

an ion conductive domain comprising a polymer comprising an ion conductive repeating unit

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS10497972B2Electrolyte, and negative electrode and lithium battery including the same

Publication Date: 2019.12.03 SAMSUNG ELECTRONICS CO LTD

AI summary

An electrolyte composition for a lithium battery includes a block copolymer and a nanoparticle composite dispersed in the block copolymer. The block copolymer includes a structural domain including a polymer having a structural repeating unit; and an ion conductive domain including a polymer having an ion conductive repeating unit, a rubbery domain including a polymer having a rubber repeating unit, or a hard domain comprising a polymer having an olefin-based repeating unit.