Block Copolymer Cathode Coating for High Voltage Stability

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Solution Overview

Problem

Conventional lithium batteries face instability and side reactions at high voltages due to the generation of by-products and side reactions between the cathode and electrolyte, leading to reduced performance and lifespan.

Innovation Solution

A cathode with a coating layer made of a block copolymer, comprising a structure domain and an ion conductive domain, is used to suppress side reactions and enhance stability at high voltages, comprising a polystyrene-b-polyacrylonitrile block copolymer with a specific weight percentage range that provides mechanical strength and ion conduction pathways.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a conventional cathode is used to achieve high voltage operation, then energy density is improved, but side reactions and by-product generation increase

Engineering Contradiction:

Improveenergy densityVSAvoidside reactions and by-products

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

A coating layer comprising a block copolymer is introduced as an intermediary between the cathode active material and the electrolyte. This coating layer suppresses side reactions and by-product generation while allowing high voltage operation, thereby resolving the contradiction between energy density improvement and harmful factor generation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The coating layer is formed using a block copolymer that contains both a structure domain (first block) and an ion conductive domain (second block). This composite material structure provides both mechanical strength and ion conductivity, enabling the cathode to maintain high voltage stability while preventing harmful side reactions.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a coating layer is added to suppress side reactions, then stability is improved, but device complexity increases

Engineering Contradiction:

Improvestability at high voltageVSAvoidcoating layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The block copolymer's composition parameters are optimized by controlling the weight ratio between the first block (structure domain) and second block (ion conductive domain). By adjusting these parameters within specific ranges, the coating layer achieves both high stability and simplified structure, avoiding excessive complexity while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

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 cathode coating layer effectively stabilizes the lithium battery at high voltages, improving its mechanical strength, ion conductivity, and lifespan characteristics by preventing side reactions and maintaining performance over multiple charging/discharging cycles.

Implementation Method 1

at least one second block that constitutes an ion conductive domain

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS10581080B2Cathode and lithium battery including the same

Publication Date: 2020.03.03 SAMSUNG ELECTRONICS CO LTD

AI summary

A cathode includes a cathode active material layer including a cathode active material; and a coating layer that is disposed on the cathode active material layer and that includes a block copolymer, wherein the block copolymer includes at least one first block that forms a structure domain and a second block that forms an ion conductive domain, and a total amount of the first block is in a range of about 20 weight percent to about 80 weight percent based on the total weight of the block copolymer.