Pseudo-Spinel Positive Electrode Material for Battery Cycle Stability
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Solution Overview
Problem
Current lithium-ion secondary batteries face challenges in achieving high energy density, improved cycle performance, safety, and long-term reliability, particularly in maintaining capacity during charge and discharge cycles.
Innovation Solution
A positive electrode active material composed of lithium, cobalt, nickel, aluminum, magnesium, and fluorine with specific atomic ratios and particle size distributions is developed, which enhances capacity and cycle performance by forming a pseudo-spinel crystal structure, thereby stabilizing the crystal structure during high-voltage charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the carried amount of positive electrode active material is increased to increase energy density, then energy density is improved, but cycle performance and capacity retention deteriorate
Solution Approach 1:
The patent changes the crystal structure parameter from conventional layered structure to pseudo-spinel structure, and optimizes atomic ratios (Li:Co:Ni:Al:Mg = 1:1-x-y-z-w:a:b:c:d where a≥0.05, b≥0.05, c≥0.1, d≥0.01) to achieve high capacity retention of 80% or more after 500 cycles while maintaining high energy density
Solution Approach 2:
The patent creates a composite positive electrode active material containing multiple elements (Li, Co, Ni, Al, Mg, O, F) in specific ratios within a pseudo-spinel crystal structure, combining the advantages of different elements to achieve both high energy density and excellent cycle performance
2Quantity of substance
If high voltage charging is performed to increase capacity, then capacity is improved, but crystal structure stability deteriorates
Solution Approach 1:
The patent changes the crystal structure to pseudo-spinel type and optimizes atomic ratios to enable stable operation at high voltages of 4.3V or higher, achieving capacity of 200mAh/g or more while maintaining crystal structure stability through the presence of Al, Mg, and F elements that reinforce the lattice structure
3Speed
If particle size is reduced to improve charge-discharge rate, then charge-discharge rate is improved, but manufacturing precision and powder packing density worsen
Solution Approach 1:
The patent optimizes particle size parameters to a specific range of 3μm to 10μm, which balances the charge-discharge rate improvement from smaller particles with sufficient powder packing density and manufacturing control, achieving capacity retention of 80% or more after 500 cycles
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 proposed material achieves high capacity and excellent charge and discharge cycle performance, inhibiting capacity decline and ensuring safety and reliability in lithium-ion secondary batteries.
Implementation Method 1
A positive electrode active material composed of lithium, cobalt, nickel, aluminum, magnesium, and fluorine with specific atomic ratios and particle size distributions is developed, which enhances capacity and cycle performance by forming a pseudo-spinel crystal structure, thereby stabilizing the crystal structure during high-voltage charging and discharging.
Implementation Method 2
In particular, one embodiment of the present invention relates to a positive electrode active material that can be used for a secondary battery
Data Source
AI summary
A positive electrode active material that has high capacity and excellent charge and discharge cycle performance for a secondary battery is provided. The positive electrode active material includes a group of particles including a first group of particles and a second group of particles. The group of particles includes lithium, cobalt, nickel, aluminum, magnesium, oxygen, and fluorine. When the number of cobalt atoms included in the group of particles is taken as 100, the number of nickel atoms is greater than or equal to 0.05 and less than or equal to 2, the number of aluminum atoms is greater than or equal to 0.05 and less than or equal to 2, and the number of magnesium atoms is greater than or equal to 0.1 and less than or equal to 6. When particle size distribution in the group of particles is measured by a laser diffraction and scattering method, the first group of particles has a first peak and the second group of particles has a second peak; the first peak has a local maximum value at longer than or equal to 2 μm and shorter than or equal to 4 μm, and the second peak has a local maximum value at longer than or equal to 9 μm and shorter than or equal to 25 μm.