Lithium Nickel Composite Oxide Cathode Crystallite Control

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Solution Overview

Problem

Lithium nickel composite oxide cathode active materials in non-aqueous electrolyte secondary batteries exhibit inferior cyclability and low-temperature output characteristics, with existing solutions either improving cyclability at the expense of discharge capacity or enhancing discharge capacity without adequately addressing low-temperature performance.

Innovation Solution

A cathode active material composed of lithium nickel composite oxide with controlled crystallite diameter and crystallinity, achieved by using a nickel composite hydroxide precursor with specific metal elements and calcination conditions, to enhance low-temperature output characteristics while maintaining charge/discharge capacity and cyclability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium nickel composite oxide is used as cathode active material to increase charge capacity and discharge capacity, then the energy density is improved, but the cyclability becomes inferior

Engineering Contradiction:

Improvecharge capacityVSAvoidcyclability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the crystallite diameter (1200-1600 Å) and crystallinity (half width 0.45°-0.8°) of the lithium nickel composite oxide cathode active material. These parameter optimizations enable the material to achieve both high charge/discharge capacity and improved cyclability, resolving the contradiction between energy density and reliability.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If lithium nickel composite oxide is used to increase charge capacity and discharge capacity, then the energy density is improved, but the low-temperature output characteristics deteriorate

Engineering Contradiction:

Improvecharge capacityVSAvoidlow-temperature output characteristics

Core Design Contradiction:

Quantity of substanceVSPower

Solution Approach 1:

The patent resolves this contradiction by optimizing specific parameters: controlling crystallite diameter within 1200-1600 Å and crystallinity half width at 0.45°-0.8°. These parameter changes enable the cathode material to maintain high charge capacity while significantly improving low-temperature output characteristics, achieving a 20% or more increase in output at -30°C.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If elements are added or substituted into lithium nickel composite oxide to improve cyclability, then the cyclability is improved, but the discharge capacity decreases

Engineering Contradiction:

ImprovecyclabilityVSAvoiddischarge capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of adding or substituting elements that reduce discharge capacity, the patent achieves improved cyclability through parameter optimization: controlling crystallite diameter (1200-1600 Å) and crystallinity (half width 0.45°-0.8°). This approach maintains high discharge capacity while improving cyclability, avoiding the trade-off present in conventional approaches.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If elements are added or substituted into lithium nickel composite oxide to improve cyclability, then the cyclability is improved, but the low-temperature output characteristics worsen

Engineering Contradiction:

ImprovecyclabilityVSAvoidlow-temperature output characteristics

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent resolves this contradiction by optimizing crystallite diameter (1200-1600 Å) and crystallinity (half width 0.45°-0.8°) without adding elements that harm low-temperature performance. This parameter control approach simultaneously improves cyclability and enhances low-temperature output characteristics, achieving a 20% or more increase in output at -30°C while maintaining reliable cycling performance.

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 solution results in a non-aqueous electrolyte secondary battery with improved low-temperature output characteristics, achieving a 20% or more increase in output at -30°C compared to conventional batteries, while maintaining battery performance.

Implementation Method 1

achieved by using a nickel composite hydroxide precursor with specific metal elements and calcination conditions

Methodology Applied

Scientific EffectCalcination: Heat Treatment

Data Source

PatentUS9553311B2Positive electrode active material for non-aqueous electrolyte secondary battery and production method for same, precursor for positive electrode active material, and non-aqueous electrolyte secondary battery using positive electrode active material

Publication Date: 2017.01.24 SUMITOMO METAL MINING CO LTD

AI summary

Provided is a cathode active material for a non-aqueous electrolyte secondary battery capable of obtaining high initial discharge capacity and good output characteristics at low temperature. In order to achieve this, a cathode active material that is a lithium nickel composite oxide composed of secondary particles that are an aggregate of primary particles is expressed by the general expression: Liw(Ni1-x-yCoxAly)1-zMzO2 (where 0.98≦w≦1.10, 0.05≦x≦0.3, 0.01≦y≦0.1, 0≦z≦0.05, and M is at least one metal element selected from a group consisting of Mg, Fe, Cu, Zn and Ga), and where the crystallite diameter at (003) plane of that lithium nickel composite oxide that is found by X-ray diffraction and the Scherrer equation is within the range of 1200 Å to 1600 Å is used as the cathode material.