NCM Cathode Crystallite Control for Thermal Stability and Cycle Life
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Solution Overview
Problem
Positive electrodes based on lithium nickel composite oxides tend to have low thermal stability and cycling performance due to heat generation and oxygen release during charging or discharging, and substituting nickel with an added element to improve thermal stability often compromises cycling performance.
Innovation Solution
A nickel-cobalt-manganese-based active material with specific crystallite sizes and particle distributions, synthesized through controlled calcination steps, is used to enhance thermal stability and cycling performance, with a weight decrease ratio per minute in thermal mass spectrometry of 0.46% or less and a cycle capacity retention of 93.8% or more.
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 cycling performance becomes lower
Solution Approach 1:
The patent changes the crystallite size parameter to 460 Å or more, which fundamentally alters the thermal and electrochemical behavior of the NCM-based active material. This parameter change enables simultaneous achievement of high thermal stability and excellent cycling performance without requiring nickel substitution, thereby resolving the technical contradiction between thermal stability and cycling performance
2Quantity of substance
If a lithium nickel composite oxide is used to achieve high capacity, then capacity is improved, but thermal stability and cycling performance deteriorate due to heat generation and oxygen release
Solution Approach 1:
The patent applies parameter changes by controlling the crystallite size to 460 Å or more, which suppresses the harmful thermal decomposition reactions (heat generation and oxygen release) while preserving the high capacity characteristics of lithium nickel composite oxide. This resolves the contradiction between high capacity and thermal stability
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 achieves improved thermal stability and cycling performance for nickel-cobalt-manganese-based positive electrodes, maintaining high capacity retention and controlled weight loss during thermal testing, effectively addressing the limitations of existing materials.
Implementation Method 1
A positive electrode including a lithium nickel composite oxide is likely to generate heat and release oxygen during charging or discharging, and tends to be low in thermal stability
Implementation Method 2
a weight decrease amount in thermal mass spectrometry at 120 to 600°C and a temperature increase rate of 5°C/min is 12 mass% or less
Data Source
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AI summary
The present disclosure relates to a positive electrode NCM (nickel-cobalt-manganese)-based active material (11) in which a crystallite size is 460 Å or more, and also relates to 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-based active material (11) that can exhibit an improved cycling performance 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).