NCM Cathode Crystallite Control for Thermal Stability and Cold Output
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Solution Overview
Problem
Positive electrodes based on lithium nickel composite oxides tend to generate heat and release oxygen during charging or discharging, leading to low thermal stability and low-temperature low-SOC output properties, which are further compromised when elements substitute for nickel to improve thermal stability.
Innovation Solution
A nickel-cobalt-manganese (NCM)-based active material with controlled crystallite size, secondary particle diameter, and thermal mass spectrometry characteristics, including a weight decrease amount and rate, is developed to enhance both thermal stability and low-temperature low-SOC output properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an added element substitutes for a nickel element to improve thermal stability, then thermal stability is improved, but low-temperature low-SOC output property deteriorates
Solution Approach 1:
The invention changes the crystallite size parameter to a specific range (460-580 Å) to simultaneously achieve high thermal stability and good low-temperature low-SOC output properties, avoiding the need for element substitution that would compromise performance
Solution Approach 2:
The invention uses a composite structure with controlled crystallite size and aggregated particle morphology (secondary particles with D50 of 14-18 μm) to achieve both thermal stability and electrochemical performance without requiring added elements
2Power
If a lithium nickel composite oxide is used in positive electrode, then high capacity is achieved, but thermal stability deteriorates due to heat generation and oxygen release
Solution Approach 1:
The invention optimizes the crystallite size parameter to 460-580 Å, which suppresses heat generation and oxygen release while maintaining high capacity, thereby resolving the contradiction between power and thermal stability
Solution Approach 2:
The invention creates a specific local structure with controlled crystallite size within aggregated particles, where the local crystallite dimensions provide thermal stability while the overall particle structure maintains high capacity
Data Source
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AI summary
The present disclosure relates to: a positive electrode NCM-based active material (11) in which a crystallite size is 460 Å or more; a positive electrode (20) including the positive electrode NCM-based active material (11); and a battery (100) including the positive electrode (20). According to the present disclosure, there are provided: the positive electrode NCM (nickel-cobalt-manganese)-based active material (11) that can exhibit an improved low-temperature low-SOC output property as well as high thermal stability; the positive electrode (20) including the positive electrode NCM-based active material (11); and the battery (100) including the positive electrode (20).