Nickel Cathode Particle Dispersion for Output and Crack Resistance

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Solution Overview

Problem

Existing positive electrode active materials for nonaqueous electrolyte secondary batteries face challenges in achieving high output characteristics and durability, particularly due to particle cracking during electrode formation and charge/discharge cycles.

Innovation Solution

A method for producing lithium-transition metal composite oxide particles with a specific particle size distribution and composition, involving the preparation of nickel-containing composite oxide particles, a heat treatment with a lithium compound, and a dry dispersion treatment followed by contact with a liquid medium to achieve uniform particle size and reduced grain boundaries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the size of aggregated primary particles is reduced and hollow structure is introduced to increase BET specific surface area, then output characteristics are improved, but cracks occur in secondary particles during pressurization and charge/discharge cycles, reducing durability

Engineering Contradiction:

Improveoutput characteristicsVSAvoiddurability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The invention changes the particle size distribution parameters by controlling the ratio 1D90/1D10 to be 3.0 or less, which optimizes the balance between surface area and structural integrity. This parameter control prevents excessive particle size reduction that would lead to cracking while maintaining high output characteristics through adequate surface area.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite oxide particles containing multiple metal elements (Ni, Co, Mn, Al) in specific ratios to create a material structure that combines high surface area with enhanced mechanical strength. The composite composition allows the particles to maintain structural integrity during charge/discharge cycles while providing the necessary surface area for high output performance.

Inventive Principle:

Principle #40Composite materials

2Reliability

If lithium compound is added to adjust Li/(Ni+Co+Mn) ratio for improved electrochemical performance, then capacity retention is enhanced, but particle size distribution may become uneven affecting manufacturing consistency

Engineering Contradiction:

Improvecapacity retentionVSAvoidparticle size distribution uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention performs preliminary classification of composite oxide particles before adding the lithium compound, ensuring that particles are already in the desired size range (1D90/1D10 ≤ 3.0). This preliminary action prevents particle size distribution issues that would otherwise occur during subsequent heat treatment with lithium compound, maintaining both capacity retention and manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention employs a continuous heat treatment process at controlled temperatures (800-1000°C) for specific durations (5-20 hours) that simultaneously achieves lithium compound incorporation and maintains particle size uniformity. The continuous processing ensures even distribution of lithium throughout the particle structure without causing aggregation or size variation.

Inventive Principle:

Principle #20Continuity of useful 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 method efficiently produces positive electrode active material particles with improved output characteristics and durability, reducing particle cracking and maintaining high capacity retention and power density.

Implementation Method 1

subjecting the raw material mixture to a heat treatment to obtain a heat-treated material

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

subjecting the heat-treated material to a dispersion treatment by a dry process to obtain a first dispersion

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS20250070158A1Method of producing positive electrode active material for nonaqueous electrolyte secondary battery

Publication Date: 2025.02.27 NICHIA CORP

AI summary

A method of producing a positive electrode active material for a nonaqueous electrolyte secondary battery, the method includes preparing nickel-containing composite oxide particles having a ratio 1D90/1D10 of a 90% particle size 1D90 to a 10% particle size 1D10 in volume-based cumulative particle size distribution of 3 or less; obtaining a raw material mixture containing the composite oxide particles and a lithium compound and having a ratio of a total number of moles of lithium to a total number of moles of metal elements contained in the composite oxide in a range of 1 to 1.3; subjecting the raw material mixture to a heat treatment to obtain a heat-treated material; subjecting the heat-treated material to a dry-dispersion treatment to obtain a first dispersion; and bringing the first dispersion into contact with a liquid medium to obtain a second dispersion.