Fluoride-Coated Cathode Material With Carbonate-Stabilized Interface

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Solution Overview

Problem

Batteries using positive electrode materials coated with lithium-containing fluoride experience increased internal resistance due to the deterioration of the coating layer at the interface with alkaline components on the surface of the positive electrode active material, leading to resistance layer formation during charge and discharge.

Innovation Solution

A coated active material is developed with a controlled amount of lithium carbonate on the surface of the positive electrode active material, combined with a lithium-containing fluoride coating layer, to suppress the reaction between alkaline components and the coating layer, thereby reducing interface resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lithium-containing fluoride coating layer is applied to the positive electrode active material, then oxidation resistance is improved, but internal resistance increases due to coating layer deterioration at the interface with alkaline components

Engineering Contradiction:

Improveoxidation resistanceVSAvoidinternal resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Lithium carbonate is introduced as an intermediary substance between the positive electrode active material and the lithium-containing fluoride coating layer. This intermediary layer prevents direct contact and harmful reactions between alkaline components on the active material surface and the coating layer, thereby maintaining coating layer stability and preventing internal resistance increase while preserving oxidation resistance benefits

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite structure consisting of three components: positive electrode active material, lithium carbonate intermediate layer, and lithium-containing fluoride coating layer. This composite approach combines the oxidation resistance of the fluoride coating with the buffering capability of lithium carbonate, achieving both protection functions simultaneously without the harmful interface reactions

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If the amount of lithium carbonate on the surface is increased to suppress alkaline component reactions, then interface stability is improved, but excessive carbonate may increase resistance

Engineering Contradiction:

Improveinterface stabilityVSAvoidresistance

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the concentration parameter of lithium carbonate on the positive electrode active material surface, specifying it should be 0.01 mass % or more and 5 mass % or less. This parameter optimization ensures sufficient buffering of alkaline components to stabilize the interface while preventing excessive carbonate accumulation that would increase resistance and harm battery performance

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 coated active material effectively reduces internal battery resistance by stabilizing the surface alkaline components and enhancing ionic conductivity, preventing resistance layer formation and oxidative decomposition.

Implementation Method 1

a controlled amount of lithium carbonate on the surface of the positive electrode active material, combined with a lithium-containing fluoride coating layer, to suppress the reaction between alkaline components and the coating layer

Methodology Applied

Scientific EffectChemical buffering:

Implementation Method 2

the coating layer includes a lithium-containing fluoride... enhancing ionic conductivity, preventing resistance layer formation

Methodology Applied

Scientific EffectIonic conductivity enhancement:

Implementation Method 3

preventing resistance layer formation and oxidative decomposition

Methodology Applied

Scientific EffectOxidation prevention: Oxidation

Data Source

PatentUS20260074231A1Coated active material, coated active material production method, positive electrode material and battery

Publication Date: 2026.03.12 PANASONIC HOLDINGS CORP

AI summary

A coated active material of the present disclosure includes: a positive electrode active material; lithium carbonate present on a surface of the positive electrode active material; and a coating layer coating at least a portion of the surface of the positive electrode active material. The coating layer includes a lithium-containing fluoride. When a mass of the lithium carbonate present on the surface of the positive electrode active material is measured by neutralization titration, a proportion R1 of the mass of the lithium carbonate in a mass of the positive electrode active material is 0.43% or more and 1.4% or less.