Single-Crystal Cathode Material With Al-F Surface for Leakage Control

Solution Overview

Problem

Existing positive electrode active materials for solid-state batteries suffer from undesirable side reactions at the interface with solid-state electrolytes, leading to high leakage capacity, which deteriorates electrochemical properties and reduces battery durability.

Innovation Solution

A single-crystalline positive electrode active material powder comprising lithium, nickel, manganese, or cobalt, with specific atomic ratios of aluminum and fluorine, is developed to enhance the interfacial contact and reduce leakage current, achieved through a manufacturing process involving specific heating temperatures and surface treatments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If single-crystalline positive electrode active material powder is used to ensure good surface contact, then surface contact quality is improved, but side reactions at the interface increase leading to higher leakage capacity

Engineering Contradiction:

Improvesurface contact qualityVSAvoidleakage capacity

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a dual-structure particle system where the interior maintains single-crystalline morphology for good surface contact, while the surface is covered with amorphous material that suppresses side reactions. This local differentiation allows each region to perform its optimal function - the single-crystalline core ensures mechanical contact quality while the amorphous surface layer provides chemical stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining single-crystalline positive electrode active material with an amorphous coating layer on its surface. This composite structure integrates the advantages of both materials: the single-crystalline interior provides structural integrity and surface contact, while the amorphous exterior reduces harmful interface reactions with the solid-state electrolyte.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If polymer solid-state electrolyte is used to enable battery operation, then battery functionality is achieved, but metal dissolution occurs at higher temperatures increasing leakage capacity

Engineering Contradiction:

Improvebattery operation capabilityVSAvoidelectrochemical stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The amorphous surface layer acts as an intermediary between the single-crystalline positive electrode active material and the polymer solid-state electrolyte. This intermediate layer prevents direct harmful interactions while allowing beneficial electrochemical reactions, thereby protecting the electrode material from metal dissolution caused by the polymer electrolyte at elevated temperatures.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If conventional positive electrode active material is used to achieve battery capacity, then energy storage is achieved, but durability is reduced due to interface side reactions

Engineering Contradiction:

Improvebattery capacityVSAvoidbattery durability

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by creating a dual-structure particle system where the interior maintains single-crystalline morphology for good surface contact, while the surface is covered with amorphous material that suppresses side reactions. This local differentiation allows each region to perform its optimal function - the single-crystalline core ensures mechanical contact quality while the amorphous surface layer provides chemical stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining single-crystalline positive electrode active material with an amorphous coating layer on its surface. This composite structure integrates the advantages of both materials: the single-crystalline interior provides structural integrity and surface contact, while the amorphous exterior reduces harmful interface reactions with the solid-state electrolyte.

Inventive Principle:

Principle #40Composite materials

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 material significantly reduces total leaked capacity, improving battery durability and performance by achieving a synergistic effect between the composition and single-crystalline morphology, resulting in a reduced leakage current and enhanced electrochemical stability.

Implementation Method 1

the monolithic morphology guarantees a good surface contact between the solid-state electrolyte and the positive electrode active material particles

Methodology Applied

Scientific EffectSurface contact:

Implementation Method 2

an improved Qtotal, thus a reduced leaked capacity, is achieved in a lithium ion battery using a positive electrode active material powder according to the present invention

Methodology Applied

Scientific EffectSurface treatment effect:

Data Source

PatentUS20230411615A1A positive electrode active material for rechargeable batteries

Publication Date: 2023.12.21 UMICORE(BE)

AI summary

The present invention provides a positive electrode active oxide material for rechargeable batteries, comprising lithium, nickel, and at least one metal selected from the group comprising manganese and cobalt, whereby said positive electrode active material has a single-crystalline morphology and said surface layer further comprises aluminum and fluorine, wherein the atomic ratio of Al to a total amount of Ni, Mn, and/or Co of 1.0 to 7.0, and wherein said surface layer has an atomic ratio of F to a total amount of Ni, Mn, and/or Co of 0.5 to 6.0, as determined by XPS analysis.