Glassy-Coated High-Ni NCM Cathode Material for Thermal Stability
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Solution Overview
Problem
High-Ni NCM-based lithium composite transition metal oxides for secondary batteries face limitations in thermal stability and particle strength, leading to reduced battery lifetime and stability due to increased nickel content and lithium by-products, as well as particle breakage during electrode rolling.
Innovation Solution
A positive electrode active material with a lithium composite transition metal oxide containing nickel, cobalt, and manganese, coated with a glassy layer composed of boron, aluminum, or silicon compounds, where nickel content is 60 mol% or more, and manganese exceeds cobalt, enhancing thermal stability and particle strength while reducing lithium by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel content is increased to secure high capacity, then capacity characteristics are improved, but thermal stability is rapidly reduced
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core contains high-nickel NCM material (Ni≥60 mol%) for high capacity, while the outer shell contains low-nickel NCM material (Ni<60 mol%) with higher thermal stability. This spatial differentiation of composition allows the high-capacity core to be protected by the thermally stable shell, resolving the contradiction between high nickel content and thermal stability.
Solution Approach 2:
The patent uses composite materials by combining high-nickel NCM particles with low-nickel NCM particles to form a composite structure. The high-nickel component provides high capacity while the low-nickel component provides thermal stability, and their composite arrangement allows both properties to coexist in the same electrode material system.
2Quantity of substance
If nickel content is increased, then capacity characteristics are improved, but structural stability and chemical stability are reduced
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core contains high-nickel NCM material (Ni≥60 mol%) for high capacity, while the outer shell contains low-nickel NCM material (Ni<60 mol%) with higher thermal stability. This spatial differentiation of composition allows the high-capacity core to be protected by the thermally stable shell, resolving the contradiction between high nickel content and thermal stability.
3Reliability
If concentration of manganese is increased to improve thermal stability, then thermal stability is improved, but particle strength is reduced causing particle breakage
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core contains high-nickel NCM material (Ni≥60 mol%) for high capacity, while the outer shell contains low-nickel NCM material (Ni<60 mol%) with higher thermal stability. This spatial differentiation of composition allows the high-capacity core to be protected by the thermally stable shell, resolving the contradiction between high nickel content and thermal stability.
4Quantity of substance
If high-Ni positive electrode active material is used, then capacity characteristics are improved, but lithium by-products increase causing swelling phenomenon
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core contains high-nickel NCM material (Ni≥60 mol%) for high capacity, while the outer shell contains low-nickel NCM material (Ni<60 mol%) with higher thermal stability. This spatial differentiation of composition allows the high-capacity core to be protected by the thermally stable shell, resolving the contradiction between high nickel content 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 glassy coating layer improves particle strength, prevents breakage during electrode rolling, and reduces lithium by-products, resulting in enhanced high-temperature life characteristics and suppressed gas generation, thereby increasing the battery's thermal stability and lifespan.
Implementation Method 1
a glassy coating layer formed on surfaces of particles of the lithium composite transition metal oxide
Implementation Method 2
the glassy coating layer includes a glassy compound represented by Formula 1: LiaM1bOc
Data Source
AI summary
A positive electrode active material for a secondary battery includes a lithium composite transition metal oxide including nickel (Ni), cobalt (Co), and manganese (Mn), and a glassy coating layer formed on surfaces of particles of the lithium composite transition metal oxide, wherein, in the lithium composite transition metal oxide, an amount of the nickel (Ni) in a total amount of transition metals is 60 mol % or more, and an amount of the manganese (Mn) is greater than an amount of the cobalt (Co), and the glassy coating layer includes a glassy compound represented by Formula 1.LiaM1bOc [Formula 1]wherein, M1 is at least one selected from the group consisting of boron (B), aluminum (Al), silicon (Si), titanium (Ti), and phosphorus (P), and 1≤a≤4, 1≤b≤8, and 1≤c≤20.