Elastomer-Encapsulated Cathode Particles for Lithium Battery Stability

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Solution Overview

Problem

Current lithium-ion batteries face issues with low energy density, short cycle life, and safety concerns due to the limitations of existing cathode active materials, including rapid capacity decay, flammability, and the risk of thermal runaway, primarily attributed to the use of transition metal oxides which can catalyze undesirable chemical reactions and react with electrolytes.

Innovation Solution

A cathode active material layer comprising particulates of cathode active materials encapsulated in a thin layer of inorganic filler-reinforced elastomer, which provides mechanical stability, prevents direct contact with electrolytes, and enhances lithium ion conductivity, thereby mitigating the issues of rapid capacity decay and safety hazards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If transition metal oxide cathode active materials are used, then high capacity is achieved, but rapid capacity decay and safety hazards occur due to structural instability and electrolyte decomposition

Engineering Contradiction:

ImprovecapacityVSAvoidcycle life

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

An elastomer coating layer is introduced as an intermediary between the transition metal oxide cathode active material and the electrolyte. This coating prevents direct contact and harmful reactions while allowing lithium ion transport, thereby maintaining high capacity while eliminating rapid capacity decay and safety hazards.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin elastomer film is applied to encapsulate the cathode active material particles. This flexible shell accommodates volume changes during cycling, maintains structural integrity, and provides a stable interface for lithium ion conduction without undergoing decomposition.

Inventive Principle:

Principle #30Flexible shells and thin films

2Quantity of substance

If transition metal oxide cathode active materials are used, then high capacity is achieved, but safety hazards occur due to flammability and thermal runaway risk

Engineering Contradiction:

ImprovecapacityVSAvoidsafety

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The elastomer coating serves as a safety intermediary that physically isolates the transition metal oxide from the electrolyte and prevents thermal runaway. The coating is specifically selected to be non-flammable and thermally stable, thereby eliminating safety hazards while preserving the high capacity of the underlying active material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The elastomer coating transforms the inherently unsafe transition metal oxide material into a safe cathode component. The coating's stability and non-reactivity convert a material prone to thermal runaway into a safe, stable electrode that maintains the original material's high capacity advantages.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Use of energy by moving object

If conventional cathode active materials are used, then battery operation is achieved, but low energy density results due to limited specific capacity

Engineering Contradiction:

Improveenergy densityVSAvoidspecific capacity

Core Design Contradiction:

Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The elastomer coating enables the use of high-capacity transition metal oxide materials by preventing their decomposition. This intermediary layer allows the battery to achieve high energy density by utilizing materials with specific capacities exceeding 300 mAh/g without suffering from the rapid capacity decay that would otherwise limit practical energy storage.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution significantly improves the energy density and cycle life of lithium-ion batteries by preventing structural instability and electrolyte decomposition, while ensuring safer operation by encapsulating the cathode active materials within a robust and lithium-ion conductive elastomer shell.

Implementation Method 1

encapsulated by a thin layer of inorganic filler-reinforced elastomer, which provides mechanical stability, prevents direct contact with electrolytes

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 2

enhances lithium ion conductivity, thereby mitigating the issues of rapid capacity decay and safety hazards

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS11043662B2Electrochemically stable elastomer-encapsulated particles of cathode active materials for lithium batteries

Publication Date: 2021.06.22 HONEYCOMB BATTERY CO

AI summary

Provided is a lithium battery cathode electrode comprising multiple particulates of a cathode active material, wherein at least a particulate is composed of one or a plurality of particles of a cathode active material being encapsulated by a thin layer of inorganic filler-reinforced elastomer having from 0.01% to 50% by weight of an inorganic filler dispersed in an elastomeric matrix material based on the total weight of the inorganic filler-reinforced elastomer, wherein the encapsulating thin layer of inorganic filler-reinforced elastomer has a thickness from 1 nm to 10 μm, a fully recoverable tensile strain from 2% to 500%, and a lithium ion conductivity from 10−7 S/cm to 5×10−2 S/cm and the inorganic filler has a lithium intercalation potential from 1.1 V to 4.5 V (preferably 1.2-2.5 V) versus Li/Li+.