Composite Active Material Coating for Ionic Conductivity and Durability

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Solution Overview

Problem

Existing coating layers containing lithium niobate (LiNbO3) on oxide-based ceramic particles in active material particles suffer from high ionic conduction resistance and mechanical weakness, leading to decreased coverage and durability, facilitating contact between the active material particles and sulfide-based solid electrolytes.

Innovation Solution

A composite coating layer comprising a crystalline oxide-based ionic conductor as a first component and an amorphous ionic or electronic conductor as a second component, with the second component having a higher amorphous phase content, enhances adhesion and contact with the active material particles, improving coverage and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coating layer containing lithium niobate (LiNbO3) is formed on the surface of active material particles, then the ionic conduction resistance is reduced, but the mechanical strength and adhesion of the coating layer deteriorate

Engineering Contradiction:

Improveionic conduction resistanceVSAvoidmechanical strength of coating layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies composite materials by combining LiNbO3 particles (providing ionic conduction) with a binder material (providing mechanical strength and adhesion). The coating layer comprises LiNbO3 particles dispersed in a binder material, where the binder material forms a continuous phase that binds the particles together and to the active material particle surface. This composite structure allows the coating to simultaneously achieve low ionic conduction resistance (through LiNbO3) and high mechanical strength (through the binder matrix).

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The binder material acts as an intermediary between the LiNbO3 particles and the active material particle surface. It provides adhesion to the surface while holding the LiNbO3 particles in place, enabling the coating layer to maintain both electrical functionality and mechanical integrity without direct contact between LiNbO3 and the active material surface alone.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the coating layer is made thinner to reduce ionic conduction resistance, then the ionic conductivity improves, but the coverage rate and durability of the coating layer decrease

Engineering Contradiction:

Improveionic conductivityVSAvoiddurability and coverage rate of coating layer

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The composite coating structure allows for optimized thickness where the binder material forms a continuous protective matrix even at thin layers, while LiNbO3 particles provide ionic conduction pathways. The binder ensures durability and complete surface coverage even when the overall coating thickness is minimized for low resistance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The coating layer exhibits local quality differentiation where the binder material provides mechanical protection and adhesion throughout the matrix, while LiNbO3 particles localized within the binder provide ionic conduction pathways. This spatial distribution allows the coating to be thin overall while maintaining both durability and ionic 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 composite coating layer improves the adhesion and contact between the active material particles and the coating layer, enhancing the coverage rate and durability, while maintaining high ionic conductivity.

Implementation Method 1

a first component formed of an oxide-based ionic conductor having a crystalline phase

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

The second component may have an amorphas phase, and a higher content of the amorphas phase than the first component

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS20260031336A1Active material composite particle and battery

Publication Date: 2026.01.29 DENSO CORP

AI summary

An active material composite particle includes an active material particle and a coating layer. The coating layer is in contact with at least a part of a surface of the active material particle. The coating layer includes a first component formed of an oxide-based ionic conductor having a crystalline phase, and a second component different from the first component. Particles constituting the first component are higher in particle strength than particles constituting the second component.