Composite Halide Coating for Cathode Materials With Lower Resistance

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Solution Overview

Problem

Conventional battery technologies face issues with electrolyte decomposition leading to increased internal resistance and decreased cycle characteristics, which affect discharge capacity and resistance values.

Innovation Solution

A coated positive electrode active material is developed, comprising a first positive electrode active material with lithium and a transition metal, coated with a layer containing a halide and a second material that can absorb and release lithium, enhancing electron conductivity and reducing direct contact with electrolytes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the active material is coated with a conventional coating material (such as lithium niobate or solid electrolyte), then electrolyte decomposition is reduced, but discharge capacity and resistance value are not sufficiently improved

Engineering Contradiction:

Improveelectrolyte decomposition resistanceVSAvoiddischarge capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The coating layer uses a composite structure comprising a first material (halide-based solid electrolyte) and a second material (positive electrode active material or transition metal compound). This composite coating provides both electrolyte decomposition resistance and improved discharge capacity, resolving the contradiction between reliability and productivity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical composition parameters of the coating layer by introducing halide-based materials with specific properties (high lithium ion conductivity, electrochemical stability). This parameter change enables the coating to simultaneously achieve protective function and enhance battery performance.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the active material is coated with conventional coating materials, then electrolyte decomposition is reduced, but internal resistance remains high

Engineering Contradiction:

Improveelectrolyte decomposition resistanceVSAvoidinternal resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The composite coating layer combines halide-based solid electrolyte (first material) with positive electrode active material or transition metal compound (second material). The halide component provides low resistance and high lithium ion conductivity, while the composite structure maintains electrolyte decomposition resistance, thus reducing internal resistance while preserving protective function.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The coating layer acts as an intermediary between the active material and electrolyte, using halide-based materials to facilitate lithium ion transport while preventing harmful electrolyte decomposition. This intermediary function simultaneously reduces resistance and maintains protection.

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 coated material improves discharge capacity and reduces resistance values, providing better battery performance and durability.

Implementation Method 1

Decomposition of an electrolyte by an active material is reduced by coating the active material with an appropriate coating material

Methodology Applied

Scientific EffectPhysical barrier (coating): Coatings

Implementation Method 2

a second material including at least one selected from the group consisting of a second positive electrode active material capable of absorbing and releasing lithium

Methodology Applied

Scientific EffectLithium ion absorption and release: Absorption (physical)

Implementation Method 3

a first material including a halide

Methodology Applied

Scientific EffectLithium ion conduction: Conduction (electrical)

Data Source

PatentEP4645450A1Coated positive electrode active material and battery using same

Publication Date: 2025.11.05 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

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AI summary

A coated positive electrode active material 13 of the present disclosure includes: a first positive electrode active material 10 including lithium and a transition metal; a coating layer 11 coating the first positive electrode active material 10. The coating layer 11 includes: a first material 14 including a halide; and a second material 15 including at least one selected from the group consisting of a second positive electrode active material capable of absorbing and releasing lithium and a compound including the transition metal. A battery 100 of the present disclosure includes: a positive electrode 23; a negative electrode 26; and an electrolyte layer disposed between the positive electrode 23 and the negative electrode 26. The positive electrode 23 includes the coated positive electrode active material 13 of the present disclosure.