Tungsten-Coated Nickel Cathode Material for Stable High-Capacity Batteries

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Solution Overview

Problem

Lithium secondary batteries face challenges in achieving extended life-span and higher capacity while maintaining chemical and mechanical stability, often resulting in defects like gas generation and explosion due to side reactions with the electrolyte, especially when using high-capacity cathode active materials.

Innovation Solution

A cathode active material for lithium secondary batteries is developed, comprising lithium-nickel metal oxide particles with a tungsten-containing coating, where the tungsten content ranges from 100 ppm to 5,000 ppm, and carbon content is 500 ppm or less, improving stability and resistance properties through the tungsten oxide barrier that suppresses side reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high-capacity cathode active material is used, then battery capacity is improved, but chemical stability and mechanical stability deteriorate

Engineering Contradiction:

Improvebattery capacityVSAvoidchemical stability and mechanical stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A tungsten-containing coating layer is applied as an intermediary between the high-capacity cathode active material and the electrolyte. This coating layer acts as a protective barrier that prevents direct contact and side reactions, thereby maintaining chemical stability while preserving the high capacity of the underlying active material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cathode structure is designed as a composite material system consisting of the high-capacity lithium-nickel metal oxide core combined with a tungsten-containing protective coating shell. This composite structure integrates the high capacity of the nickel-based material with the high stability of the tungsten-containing compound.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If high-capacity cathode active material is used, then battery capacity is improved, but life-span properties deteriorate

Engineering Contradiction:

Improvebattery capacityVSAvoidlife-span properties

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The tungsten-containing coating serves as a protective intermediary that shields the high-capacity cathode material from degradation during cycling. This barrier prevents harmful side reactions with the electrolyte that would otherwise reduce the battery's operational life, thereby extending life-span while maintaining high capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective tungsten-containing coating is applied beforehand to the cathode active material surface, creating a pre-established protective barrier. This prior cushioning prevents direct exposure to the electrolyte and potential degradation mechanisms before they can occur during battery operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If impurities and unreacted residues are present on cathode active material surface, then manufacturing is simplified, but gas generation and explosion risks increase

Engineering Contradiction:

Improvesurface cleanlinessVSAvoidgas generation and explosion risk

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The tungsten-containing coating acts as an intermediary barrier between surface impurities/unreacted residues and the electrolyte. This coating prevents direct side reactions that would generate gas, thereby eliminating explosion risks while allowing the manufacturing process to remain simple without requiring extensive surface cleaning.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of requiring complete removal of impurities and unreacted residues through complex cleaning processes, the invention converts the potential harm of these surface contaminants into a benefit by applying a protective tungsten-containing coating that prevents them from causing gas generation and explosion risks.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 tungsten-containing coating enhances high-temperature stability, capacity retention, and prevents gas generation, leading to a high-power and stable lithium secondary battery with improved life-span and resistance properties.

Implementation Method 1

a tungsten-containing coating on at least a portion of the active material particles... the tungsten oxide barrier that suppresses side reactions

Methodology Applied

Scientific EffectChemical stability enhancement through tungsten oxide barrier: Oxidation

Implementation Method 2

the tungsten-containing coating enhances high-temperature stability, capacity retention, and prevents gas generation... suppresses side reactions with the electrolyte

Methodology Applied

Scientific EffectSide reaction suppression:

Data Source

PatentEP4254559A1Cathode active material for lithium secondary battery and lithium secondary battery including the same

Publication Date: 2023.10.04 SK ON CO LTD

Figure 1~2

AI summary

A cathode active material for a lithium secondary battery according to an embodiment of the present invention includes active material particles containing a lithium-nickel metal oxide, and a tungsten-containing coating formed on at least portion of the active material particles. A content of tungsten measured by an ICP (inductively coupled plasma) is in a range from 100 ppm to 5,000 ppm, and a content of carbon measured by a CS (Carbon-Sulfur) analyzer is 500 ppm or less.