Conversion-Type Positive Electrode With Porous Inorganic Barrier Layer

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Solution Overview

Problem

Conversion-type positive electrodes in secondary energy storage devices face issues with active material dissolution in the electrolyte, leading to performance degradation and cell failure due to the loss of active material and shuttling of soluble species, which limits the potential for higher specific capacities and efficiency.

Innovation Solution

A conversion-type positive electrode is formed with a composite film and a porous inorganic layer on its surface, which restricts the migration of active material out of the electrode by adsorption and acts as an electrically insulating barrier, maintaining active material concentration and reducing cross-over to the negative electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a conversion-type positive electrode active material is used, then the theoretical energy density and specific energy are improved, but the active material dissolves in the electrolyte leading to performance degradation and cell failure

Engineering Contradiction:

Improvetheoretical energy densityVSAvoidperformance stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A thin film coating layer is applied to the surface of the conversion-type positive electrode active material particles. This coating acts as a protective barrier that prevents direct contact between the active material and the electrolyte, thereby eliminating dissolution while maintaining the high theoretical energy density of the conversion reaction mechanism.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The positive electrode is designed as a composite structure combining conversion-type active material particles with a protective coating material. This composite approach allows the system to retain the high capacity benefits of conversion reactions while the coating provides stability and prevents harmful dissolution into the electrolyte.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If a conversion-type positive electrode active material is used, then the specific energy is improved, but soluble species shuttle between electrodes causing cell failure

Engineering Contradiction:

Improvespecific energyVSAvoidshuttling of soluble species

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The thin film coating on the conversion-type positive electrode active material serves as a selective barrier that prevents soluble reaction products from detaching and shuttling to the negative electrode. This eliminates the harmful shuttling effect while preserving the high specific energy advantage of conversion reactions.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The coating material acts as an intermediary layer between the conversion-type active material and the electrolyte. It mediates the electrochemical reactions by allowing ion transport while preventing the release of soluble species into the bulk electrolyte, thereby preventing cross-over to the negative electrode.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If conversion reactions are used in the positive electrode, then the energy storage capacity is improved, but active material loss occurs due to dissolution

Engineering Contradiction:

Improveenergy storage capacityVSAvoidactive material loss

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The protective thin film coating physically confines the conversion-type active material particles, preventing them from dissolving into the electrolyte. This maintains the high energy storage capacity enabled by conversion reactions while eliminating active material loss during battery cycling.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The coating is applied in advance to the active material particles before they are assembled into the electrode. This preliminary protective action prevents dissolution from occurring in the first place, preserving the active material and maintaining high energy storage capacity throughout the battery's operational life.

Inventive Principle:

Principle #9Preliminary anti-action

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

This configuration maintains a higher specific capacity and improves cell efficiency and cycle life by preventing active material loss and reducing cross-over, thereby enhancing battery performance.

Implementation Method 1

restricts the migration of active material out of the electrode by adsorption

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

acts as an electrically insulating barrier, maintaining active material concentration and reducing cross-over to the negative electrode

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentUS20250309244A1Conversion-type positive electrode with an inorganic top layer

Publication Date: 2025.10.02 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A conversion-type positive electrode and formation thereof. The conversion-type positive electrode includes a composite film and a porous inorganic layer formed on the top surface of the composite film, where the composite film includes an electrically conductive porous material and a conversion-type positive electrode active material, and where the porous inorganic layer does not undergo a reversible redox reaction during cycling of the conversion-type positive electrode.