Cathode Active Material with Lithium-Sulfur Interlayers for Cycle Stability

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Solution Overview

Problem

Lithium secondary batteries face challenges in achieving long lifespan, high capacity, and operational stability due to non-uniform chemical structures and deformation of lithium-transition metal composite oxide particles during charging and discharging.

Innovation Solution

The development of a cathode active material for lithium secondary batteries, comprising lithium-transition metal composite oxide particles with a plurality of primary particles, where a lithium-sulfur-containing portion with a monoclinic crystal structure is formed between the primary particles. This is achieved through a manufacturing process involving the use of a sulfonyl-based compound aqueous solution without water washing treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If water washing process is used to remove lithium salt impurities, then impurity removal is achieved, but particle surface damage occurs and impurity removal is insufficient

Engineering Contradiction:

Improvelithium salt impurity removalVSAvoidparticle surface damage

Core Design Contradiction:

Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes lithium salt impurities from the cathode active material surface through a controlled washing process using organic solvents, separating the impurities from the main particle structure while minimizing surface damage

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the washing parameters by using organic solvents instead of water, and controls washing time, temperature, and agitation to optimize impurity removal while protecting particle integrity. The washing process parameters are specifically adjusted to prevent surface damage

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If lithium-transition metal composite oxide structure deforms during charging and discharging, then battery capacity increases, but life-span stability and capacity maintenance are reduced

Engineering Contradiction:

Improvebattery capacityVSAvoidlife-span stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies surface coating and modification treatments to the cathode active material particles before battery assembly, creating a protective layer that cushions and absorbs structural stress during charging and discharging cycles, preventing deformation while maintaining capacity

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses composite cathode active materials combining lithium-transition metal oxides with other materials that provide structural stability, creating a composite structure that maintains both high capacity and long-term stability by preventing particle degradation

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If non-uniform chemical structure is caused by lithium precipitation, then manufacturing process is simplified, but desired capacity and life-span cannot be achieved

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidchemical structure uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality control by ensuring uniform distribution of lithium and transition metals at the particle level through controlled synthesis methods, while allowing some variation in overall particle morphology. This maintains manufacturing simplicity while achieving the required chemical uniformity for performance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent performs preliminary mixing and uniform distribution of precursor materials before the synthesis reaction, ensuring homogeneous chemical composition is achieved during manufacturing. This preliminary action prevents lithium precipitation and maintains structural uniformity without complicating the overall process

Inventive Principle:

Principle #10Preliminary action

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 proposed solution enhances the operational stability and electrochemical properties of lithium secondary batteries, improving their lifespan and capacity retention by reducing resistance and protecting the primary particles with the lithium-sulfur-containing portion.

Implementation Method 1

a lithium-sulfur-containing portion with a monoclinic crystal structure is formed between the primary particles

Methodology Applied

Scientific EffectMonoclinic crystal structure: Crystallisation

Data Source

PatentUS20250293238A1Cathode active material for lithium secondary battery and lithium secondary battery including the same

Publication Date: 2025.09.18 SK ON CO LTD

AI summary

The cathode active material for a lithium secondary battery according to embodiments of the present invention includes a lithium-transition metal composite oxide particle including a plurality of primary particles, and the lithium-transition metal composite oxide particle includes a lithium-sulfur-containing portion formed between the primary particles. Thereby, it is possible to improve life-span properties and capacity properties by preventing the layer structure deformation of the primary particles and removing residual lithium.