Single-Particle NCM Cathode Material for High-Capacity Cycle Life
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Solution Overview
Problem
High nickel content in NCM positive electrode materials for lithium secondary batteries leads to increased resistance, reduced output, and decreased lifespan, necessitating the development of materials with improved electrochemical performance.
Innovation Solution
A positive electrode active material with a single particle structure, controlled grain size, and specific doping elements, manufactured through a two-stage sintering process and surface coating, to enhance lifespan and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel content in NCM positive electrode materials is increased to achieve high capacity, then capacity is improved, but resistance increases and lifespan decreases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core region contains high nickel content (0.8-0.95) for high capacity, while the outer shell region has reduced nickel content (0.5-0.8) to降低 resistance and improve lifespan. This spatial variation in composition allows different regions to perform different functions, resolving the contradiction between capacity and reliability.
Solution Approach 2:
The patent uses composite materials by combining multiple elements (Ni, Co, Mn) in specific ratios and creating a composite structure with doped elements (Al, Mg, Ca, etc.) in the outer shell. This composite approach allows the material to simultaneously achieve high capacity from the nickel-rich core and improved stability from the multi-element shell, resolving the lifespan issue.
2Quantity of substance
If nickel content in NCM positive electrode materials is increased to achieve high capacity, then capacity is improved, but resistance increase rate increases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core region contains high nickel content (0.8-0.95) for high capacity, while the outer shell region has reduced nickel content (0.5-0.8) to降低 resistance and improve lifespan. This spatial variation in composition allows different regions to perform different functions, resolving the contradiction between capacity and reliability.
Solution Approach 2:
The patent uses composite materials by combining multiple elements (Ni, Co, Mn) in specific ratios and creating a composite structure with doped elements (Al, Mg, Ca, etc.) in the outer shell. This composite approach allows the material to simultaneously achieve high capacity from the nickel-rich core and improved stability from the multi-element shell, resolving the lifespan issue.
3Quantity of substance
If nickel content in NCM positive electrode materials is increased to achieve high capacity, then capacity is improved, but gas generation increases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core region contains high nickel content (0.8-0.95) for high capacity, while the outer shell region has reduced nickel content (0.5-0.8) to降低 resistance and improve lifespan. This spatial variation in composition allows different regions to perform different functions, resolving the contradiction between capacity and reliability.
Solution Approach 2:
The patent uses composite materials by combining multiple elements (Ni, Co, Mn) in specific ratios and creating a composite structure with doped elements (Al, Mg, Ca, etc.) in the outer shell. This composite approach allows the material to simultaneously achieve high capacity from the nickel-rich core and improved stability from the multi-element shell, resolving the lifespan issue.
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 material achieves excellent lifespan characteristics, reduced resistance increase rate, and decreased gas generation, while maintaining high capacity and energy density.
Implementation Method 1
mixing the metal hydroxide particle, a lithium raw material, and a doping raw material, followed by sintering to obtain a lithium metal oxide
Implementation Method 2
The sintering step includes performing a first sintering process and continuously performing a second sintering process
Implementation Method 3
supplying the metal salt aqueous solution to a coprecipitation reactor to obtain a metal hydroxide
Data Source
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AI summary
The present embodiments relate to a positive electrode active material, a method for manufacturing the same, and a lithium secondary battery comprising the same. The positive electrode active material according to an embodiment may have a single particle structure with a D50 of 2 to 7 µm, and the number of grains measured within one particle may be 20 or less as determined by ASTAR analysis.