Lithium Metal Oxide Cathode Composition for High-Rate Discharge

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

There is a need to improve the rate characteristic of lithium secondary batteries, which refers to the ratio of discharge capacity at high current to that at low current, to enhance battery performance under large current applications.

Innovation Solution

A lithium metal composite oxide is developed with specific compositional and structural properties, including a layered rock salt crystal structure, controlled Me site occupancy, particle strength, and particle size, to enhance the rate characteristic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional lithium metal composite oxides are used, then basic battery function is maintained, but rate characteristic is insufficient

Engineering Contradiction:

Improverate characteristicVSAvoiddischarge capacity maintenance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention changes key parameters of the lithium metal composite oxide: controlling Me site occupancy at lithium sites to not more than 4.0% and adjusting particle strength to 100-200 MPa. These parameter changes enable the material to maintain high discharge capacity at high current rates while ensuring reliable battery performance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite lithium metal oxide containing Li, Ni, and alkaline earth metal elements (M1) in specific proportions defined by the compositional formula. This composite structure combines the benefits of different elements to achieve both improved rate characteristic and maintained discharge capacity reliability.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If Me site occupancy at lithium sites is increased, then structural stability is improved, but rate characteristic deteriorates

Engineering Contradiction:

Improvestructural stabilityVSAvoidrate characteristic

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The invention optimizes the Me site occupancy parameter to not more than 4.0%, which is a critical threshold that balances structural stability with rate characteristic. This parameter control prevents excessive metal atom migration to lithium sites while maintaining sufficient structural integrity for battery operation.

Inventive Principle:

Principle #35Parameter changes

3Strength

If particle strength is increased to improve structural integrity, then manufacturing robustness is improved, but discharge capacity at high current is reduced

Engineering Contradiction:

Improveparticle strengthVSAvoiddischarge capacity at high current

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The invention identifies an optimal particle strength range of 100-200 MPa that balances structural integrity with high-rate performance. Particles within this strength range maintain sufficient mechanical robustness for manufacturing while allowing adequate lithium ion diffusion for high discharge capacity at elevated current rates.

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 lithium metal composite oxide improves the rate characteristic of lithium secondary batteries, ensuring higher discharge capacity at high current rates.

Implementation Method 1

lithium metal composite oxide that contains at least Li, Ni, and an element M1 which is an alkaline earth metal element... layered rock salt crystal structure

Methodology Applied

Scientific EffectIon insertion/extraction: Diffusion

Implementation Method 2

The Me site occupancy at lithium sites of a layered rock salt crystal structure, determined by Rietveld analysis of the diffraction peaks obtained from powder X-ray diffraction using CuKα radiation

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentEP4624421A1Lithium-metal complex oxide, positive electrode active material for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery

Publication Date: 2025.10.01 SUMITOMO METAL MINING CO LTD

Figure 1~2

AI summary

A lithium metal composite oxide that contains at least Li, Ni, and an element M1 which is an alkaline earth metal element, and satisfies (1) and (2). (1) The Me site occupancy at lithium sites of a layered rock salt crystal structure, determined by Rietveld analysis of the diffraction peaks obtained from powder X-ray diffraction using CuKα radiation, is not more than 4.0%. (2) The particle strength of the lithium metal composite oxide is greater than 100 MPa but less than 200 MPa.