Single-Particle Cathode Composition for High-Nickel Thermal Stability
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Solution Overview
Problem
Lithium nickel cobalt metal oxides used in lithium secondary batteries face limitations due to poor thermal stability and structural instability, especially when nickel content is increased to enhance capacity, leading to rapid oxygen desorption and reduced battery life.
Innovation Solution
A lithium transition metal oxide positive electrode active material doped with specific elements like aluminum, titanium, or strontium, containing nickel in excess of 60 mol%, is developed, with a layered structure at the center and rock-salt structure on the surface, and sintered to achieve a single particle form with improved stability and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel content is increased to enhance capacity characteristics, then reversible capacity is improved, but thermal stability deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high nickel content (0.5-0.8 mol ratio) for high capacity, while the surface shell region contains nickel content of 0.2-0.5 mol ratio for improved thermal stability. This spatial differentiation of composition allows each region to perform its specific function optimally.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel oxide core with a lithium nickel cobalt manganese oxide shell, creating a composite structure that integrates the high capacity advantage of nickel-rich materials with the thermal stability advantage of nickel-cobalt-manganese composite materials.
2Quantity of substance
If nickel content is increased to enhance capacity characteristics, then reversible capacity is improved, but structural stability deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high nickel content (0.5-0.8 mol ratio) for high capacity, while the surface shell region contains nickel content of 0.2-0.5 mol ratio for improved thermal stability. This spatial differentiation of composition allows each region to perform its specific function optimally.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel oxide core with a lithium nickel cobalt manganese oxide shell, creating a composite structure that integrates the high capacity advantage of nickel-rich materials with the thermal stability advantage of nickel-cobalt-manganese composite materials.
3Reliability
If nickel is substituted with cobalt, manganese, or aluminum to improve thermal stability, then thermal stability is improved, but reversible capacity decreases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high nickel content (0.5-0.8 mol ratio) for high capacity, while the surface shell region contains nickel content of 0.2-0.5 mol ratio for improved thermal stability. This spatial differentiation of composition allows each region to perform its specific function optimally.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel oxide core with a lithium nickel cobalt manganese oxide shell, creating a composite structure that integrates the high capacity advantage of nickel-rich materials with the thermal stability advantage of nickel-cobalt-manganese composite materials.
4Stability of the object's composition
If amount of doping element is increased to improve structural stability, then structural stability is improved, but capacity characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the doping element content within 100-1000 ppm range and optimizing the nickel content in the shell region at 0.2-0.5 mol ratio. This parameter optimization ensures sufficient structural stability while minimizing the negative impact on capacity characteristics.
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 doped lithium transition metal oxide exhibits enhanced structural and thermal stability, improving battery life and capacity retention, while preventing cracks and side reactions, thus enabling high-energy density and long-life batteries.
Implementation Method 1
a lithium transition metal oxide which is doped with doping element M2 and contains nickel in an amount of 60 mol % or more based on a total number of moles of transition metals excluding lithium, wherein the lithium transition metal oxide has a single particle form
Data Source
AI summary
A positive electrode active material includes a lithium transition metal oxide and a coating element M3-containing coating layer formed on a surface of the lithium transition metal oxide, wherein M3 comprises at least one of Al, Ti, Mg, Zr, W, Y, Sr, or Co, wherein the lithium transition metal oxide is doped with a doping element M2, wherein M2 includes at least one of Al, Ti, Mg, Zr, W, Y, Sr, Co, F, Si, Na, Cu, Fe, Ca, S, or B, wherein the lithium transition metal oxide has a single particle form, and includes a center portion having a layered structure and a surface portion having a rock-salt structure, and the total amount of the doping element M2 and the coating element M3 is in a range of 4,580 ppm to 9,120 ppm based on a total weight of the positive electrode active material.