Layered Cathode Active Material for Battery Capacity Retention
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Solution Overview
Problem
Existing lithium transition metal composite oxides used in non-aqueous electrolyte secondary batteries face challenges in maintaining capacity retention during charging/discharging cycles and suppressing decreased discharging capacity.
Innovation Solution
A positive electrode active material comprising secondary particles of lithium transition metal composite oxide with a lamellar crystal structure, specific molar ratios of Li, Ni, Mn, Co, and M, and controlled integrated intensity and crystallite size ratios, promoting smooth lithium ion intercalation and deintercalation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium transition metal composite oxide is used as positive electrode active material, then battery capacity is improved, but capacity retention during charging/discharging cycles deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molar ratio of Li:Ni:Mn:Co:M within specific ranges (1.0≤a≤1.3, 0.25≤x≤0.9, 0.05≤y≤0.5, 0.05≤z≤0.5, 0.01≤t≤0.1) and adjusting the integrated intensity ratio (I003/I104) to 1.05-1.19. These parameter optimizations resolve the contradiction by achieving both high capacity and excellent capacity retention through controlled compositional and structural parameters of the lithium transition metal composite oxide
Solution Approach 2:
The patent employs composite materials by creating a lithium transition metal composite oxide containing multiple transition metals (Ni, Mn, Co, and M where M is selected from Mg, Ca, Al, Ti, V, Cr, Fe, Cu, Zn, Zr, Nb, Mo, Ta, or W). This composite structure combines the advantages of different metals: Ni provides high capacity, Mn enhances stability, Co improves conductivity, and M adds structural reinforcement, thereby achieving both high capacity and good capacity retention simultaneously
2Quantity of substance
If lithium transition metal composite oxide is used as positive electrode active material, then battery capacity is improved, but discharging capacity decreases over time
Solution Approach 1:
The patent applies parameter changes by optimizing the molar ratios and crystal structure parameters (integrated intensity ratio I003/I104 = 1.05-1.19) to achieve both high initial capacity and sustained discharging capacity over extended periods
Solution Approach 2:
The composite lithium transition metal oxide structure with multiple transition metals provides both high capacity and long-term discharging capacity stability through synergistic effects of the different metal components
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 enhances capacity retention and suppresses discharging capacity loss in the battery, ensuring stable performance over cycles.
Implementation Method 1
promoting smooth lithium ion intercalation and deintercalation
Implementation Method 2
an integrated intensity ratio (I003/I104) of diffraction peaks of the secondary particle in an X-ray diffraction method is 1.05 to 1.19
Data Source
AI summary
A positive electrode active material includes secondary particles in each of which primary particles are aggregated, wherein each of the secondary particles is a lithium transition metal composite oxide having a lamellar crystal structure. The lithium transition metal composite oxide includes Li, Ni, Mn, Co, and M, and a molar ratio of the Li, the Ni, the Mn, the Co, and the M is Li:Ni:Mn:Co:M=a:x:y:z:t, where the M, the a, the x, the y, the z, and the t are defined as in the scope of claims for patent. An integrated intensity ratio (I003/I104) of diffraction peaks of the secondary particle in an X-ray diffraction method is 1.05 to 1.19. A crystallite size Loos of the secondary particle is 1000 Å or more.