Tapered Block Copolymer Electrolytes for Solid-State Batteries

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Solution Overview

Problem

Contemporary lithium ion batteries rely on liquid electrolytes that are thermally and electrochemically unstable due to volatility at elevated temperatures, necessitating the development of solid-state batteries with solvent-free electrolytes, while high molecular weight block copolymers offer high ionic conductivity and mechanical strength but compromise processability.

Innovation Solution

The use of tapered block copolymers with controlled glass transition temperatures and ion transport, synthesized via methods like anionic polymerization and ATRP, decouples processing temperatures from molecular weight, enabling high molecular weight polymer electrolytes with improved mechanical properties and ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high molecular weight block copolymers are used to improve ionic conductivity and mechanical strength, then the electrolyte performance is enhanced, but the processability of the material deteriorates

Engineering Contradiction:

Improveionic conductivityVSAvoidprocessability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces tapered interfaces with controlled composition gradients between blocks, changing the compositional parameters along the polymer chain. This allows high molecular weight copolymers to be processed at lower temperatures because the tapered regions reduce interfacial segregation and lower the order-disorder transition temperature, thus resolving the contradiction between achieving high molecular weight for performance and maintaining processability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite block copolymer structures combining blocks of dissimilar monomers with tapered transition regions. These composite structures integrate the beneficial properties of high molecular weight (ionic conductivity and mechanical strength) with the processing advantages of tapered interfaces, effectively combining multiple material functions to resolve the processability-performance trade-off

Inventive Principle:

Principle #40Composite materials

2Strength

If high molecular weight block copolymers are used to improve mechanical strength, then the electrolyte stability is enhanced, but the processing temperature increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidprocessing temperature

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The patent modifies the compositional parameters by introducing tapered regions with gradual transitions between blocks. This parameter change reduces the order-disorder transition temperature, allowing high molecular weight copolymers with superior mechanical strength to be processed at lower temperatures, thus resolving the contradiction between mechanical strength and processing temperature

Inventive Principle:

Principle #35Parameter changes

3Temperature

If tapered interfaces are introduced to improve processability, then the order-disorder transition temperature decreases, but the segregation strength between blocks is reduced

Engineering Contradiction:

Improveorder-disorder transition temperatureVSAvoidsegregation strength

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating tapered regions with specific compositional gradients at the interfaces between blocks, while maintaining pure block compositions in the bulk regions. This localized tapering reduces the order-disorder transition temperature for processing while preserving the segregation strength needed for nanostructure formation, as the pure blocks maintain strong segregation tendencies

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

Tapered block copolymers facilitate the creation of high molecular weight polymer electrolytes with enhanced ionic conductivity and mechanical strength, maintaining processability similar to lower molecular weight materials, thus addressing the stability and efficiency concerns of traditional lithium ion batteries.

Implementation Method 1

The tapered interfaces can impact the glass transition temperatures (Tgs) in block copolymer electrolytes, thus affecting the polymer chain mobility and the ion transport

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

Block copolymers are promising materials for alternative electrolytes in electronic devices due to their ability to self-assemble into periodically ordered structures

Methodology Applied

Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 3

The tapered interfaces can impact the glass transition temperatures (Tgs) in block copolymer electrolytes, thus affecting the polymer chain mobility and the ion transport

Methodology Applied

Scientific EffectPolymer chain mobility:

Data Source

PatentUS9935332B2Tapered block copolymer electrolytes

Publication Date: 2018.04.03 UNIVERSITY OF DELAWARE

AI summary

Copolymers useful as components of polymer electrolytes are provided in which the copolymer comprises at least one block sequence represented by formula (I):A—(T)—B (I)wherein A is a vinyl aromatic block, T is a tapered copolymer region copolymerized from a vinyl aromatic monomer and an oligo(oxyalkylene) acrylate monomer and B is an oligo(oxyalkylene) acrylate block.