Cathode Active Material Calcination for Low-Carbon Li-Ion Output

Solution Overview

Problem

Existing methods for producing positive electrode active materials for non-aqueous electrolyte secondary batteries face challenges in controlling carbon content, which affects the output characteristics and productivity of the batteries.

Innovation Solution

A production method that uses a nickel transition metal composite hydroxide as a precursor, with specific conditions for oxygen concentration, calcination temperature, and carbon dioxide gas concentration, to control the carbon content within a necessary minimum range without a washing process after calcination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a washing process is performed after calcination to reduce carbon content, then the output characteristics of the battery are improved, but the number of processes increases and productivity deteriorates

Engineering Contradiction:

Improveoutput characteristicsVSAvoidproductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The invention performs preliminary action by controlling the carbon content during the calcination process itself through specific atmosphere composition (oxygen concentration 3-15%, carbon dioxide concentration 0.01-10%) and temperature (800-1000°C), rather than addressing carbon content after calcination through washing. This preliminary control eliminates the need for subsequent washing steps while achieving the desired low carbon content (0.01-0.1%) for improved output characteristics.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the washing process is performed to decrease carbon content, then the output characteristics are improved, but the production cost increases

Engineering Contradiction:

Improveoutput characteristicsVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention performs preliminary action by controlling the carbon content during the calcination process itself through specific atmosphere composition (oxygen concentration 3-15%, carbon dioxide concentration 0.01-10%) and temperature (800-1000°C), rather than addressing carbon content after calcination through washing. This preliminary control eliminates the need for subsequent washing steps while achieving the desired low carbon content (0.01-0.1%) for improved output characteristics.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If excessive washing is performed to decrease carbon content, then the carbon content is reduced, but lithium is excessively eluted and oxyhydroxides are generated which deteriorate battery characteristics

Engineering Contradiction:

Improvecarbon contentVSAvoidbattery characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention performs preliminary action by controlling the carbon content during the calcination process itself through specific atmosphere composition (oxygen concentration 3-15%, carbon dioxide concentration 0.01-10%) and temperature (800-1000°C), rather than addressing carbon content after calcination through washing. This preliminary control eliminates the need for subsequent washing steps while achieving the desired low carbon content (0.01-0.1%) for improved output characteristics.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention converts the potentially harmful effect of carbon dioxide (which could form carbonates) into a beneficial control mechanism. By carefully controlling carbon dioxide concentration (0.01-10%) in the calcination atmosphere, the process utilizes carbon dioxide to control carbon content while avoiding excessive carbonate formation, thereby achieving low carbon content without the need for washing that would cause lithium elution.

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 method effectively improves the output characteristics of non-aqueous electrolyte secondary batteries by controlling carbon content, while also simplifying the production process and reducing costs, making it suitable for industrial-scale production.

Implementation Method 1

performing calcination of this obtained mixture

Methodology Applied

Scientific EffectCalcination: Heat Treatment

Implementation Method 2

making a slurry of lithium nickel composite oxide after the calcination process

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentEP3176859B1Positive electrode active material for non-aqueous electrolyte secondary battery, and method for producing same

Publication Date: 2025.01.22 SUMITOMO METAL MINING CO LTD

Figure 1~2

AI summary

Provided is a positive electrode active material that is capable of improving output characteristics when used as positive electrode material for a non-aqueous electrolyte secondary battery. A lithium mixture that is obtained by adding and mixing a lithium compound to a transition metal composite hydroxide that was obtained from a crystallization reaction undergoes calcination in an atmosphere having an oxygen concentration of 4% by volume or greater. In this calcination process, carbon dioxide gas concentration in the atmosphere while the temperature is maintained at a calcination temperature is kept at 10% by volume or less, and preferably kept at 0.01% by volume to 10% by volume. As a result, positive electrode active material is obtained that includes a lithium transition metal composite oxide that is composed of secondary particles that are formed from aggregates of plural primary particles, and that has a carbon content of 0.010% by mass to 0.100% by mass.