Layered Lithium Nickel Oxide Cathode With Gradient Doping Stability
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Solution Overview
Problem
Existing lithium secondary battery cathode active materials face challenges such as high raw material costs, thermal instability, structural instability, and electrochemical property deterioration, limiting their application in medium- and large-sized electric vehicles.
Innovation Solution
A cathode active material composed of metal oxide particles with a specific chemical formula Li a Ni x Co y M z O 2, where M is aluminum, gallium, or indium, featuring a concentration gradient and a rhombohedral structure, stabilized by doping with Group 3A metals, enhancing structural and thermal stability and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium cobalt oxide is used as cathode active material, then high capacity and high output are achieved, but high raw material cost and low thermal stability occur
Solution Approach 1:
The patent uses lithium nickel cobalt manganese oxide (NCM) composite material with specific atomic ratios (Ni: 0.7-0.9, Co: 0.05-0.3, Mn: 0.1-0.25) to combine the advantages of different metals. Nickel provides high capacity, cobalt ensures structural stability, and manganese adds thermal stability, creating a balanced composite that resolves the contradiction between power and reliability
Solution Approach 2:
The patent creates a concentration gradient structure where metal element distribution varies from particle surface to center. The surface has higher cobalt and manganese content for stability, while the interior maintains nickel-rich composition for capacity, allowing simultaneous optimization of thermal stability and battery capacity through spatially differentiated composition
2Reliability
If manganese-based spinel is used to substitute lithium cobalt oxide, then raw material cost is reduced, but capacity significantly deteriorates due to manganese elution at high temperature
Solution Approach 1:
The patent combines manganese with nickel and cobalt in specific proportions to create NCM composite material. This composite structure prevents manganese elution at high temperature while maintaining cost advantages, as the nickel and cobalt components stabilize the crystal structure and prevent manganese degradation, thereby preserving battery capacity
Solution Approach 2:
The patent optimizes the atomic ratio parameters of the composite material, specifically setting Mn content at 0.1-0.25 which is higher than conventional formulations. This parameter adjustment, combined with the presence of nickel and cobalt, enhances thermal stability and prevents capacity deterioration while maintaining cost effectiveness
3Reliability
If olivine-based cathode active material is used, then raw material cost is reduced and thermal stability is improved, but driving voltage and electric conductivity become low
Solution Approach 1:
The patent creates a layered NCM composite material that combines the thermal stability advantages of manganese-based materials with the high voltage and conductivity characteristics of nickel-based materials. The specific composition (Ni: 0.7-0.9, Co: 0.05-0.3, Mn: 0.1-0.25) ensures high electric conductivity and driving voltage while maintaining thermal stability
Solution Approach 2:
Instead of using olivine structure with low voltage characteristics, the patent inverts the approach by adopting a layered structure that inherently provides higher driving voltage and electric conductivity, while compensating for thermal stability through optimized metal composition ratios
4Power
If nickel-based cathode active material is used for high capacity and high voltage, then capacity is improved, but capacity deterioration occurs due to cation mixing and structural instability
Solution Approach 1:
The patent incorporates cobalt and manganese into the nickel-based composite material. Cobalt stabilizes the layered crystal structure and prevents cation mixing, while manganese enhances thermal and structural stability. This composite approach maintains high capacity and voltage from nickel while mitigating structural degradation
Solution Approach 2:
The patent implements a concentration gradient where cobalt and manganese are more concentrated at the particle surface to provide structural stability and prevent cation mixing, while the nickel-rich interior maintains high capacity. This spatial differentiation allows simultaneous optimization of structural stability and electrochemical performance
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 provides improved thermal and structural stability, high capacity, and efficient charge/discharge cycles, extending the battery's life span and efficiency.
Implementation Method 1
a cathode active material composed of metal oxide particles with a specific chemical formula Li a Ni x Co y M z O 2, where M is aluminum, gallium, or indium, featuring a concentration gradient and a rhombohedral structure, stabilized by doping with Group 3A metals
Implementation Method 2
the metal oxide particles has a concentration gradient at which the concentration of M is decreased from the surface of the metal oxide particle to the center thereof
Data Source
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AI summary
Provided is a metal oxide for a cathode active material of a lithium secondary battery capable of having improved structural and thermal stability, high efficiency, high capacity, and excellent cycle property and life span property, the metal oxide represented by the following Chemical Formula 1: [Chemical Formula 1] LiaNixCoyMzO2 (in Chemical Formula 1, M is any one selected from aluminum, magnesium, titanium, gallium and indium, and a, x, y and z satisfy 1.01≤a≤1.05, 0.7≤x≤0.9, 0≤y≤0.17, 0.02≤z≤0.16, and x+y+z=1, respectively).