Lithium Battery Positive Electrode Active Material Pore Distribution
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Solution Overview
Problem
Current positive electrode active materials for lithium secondary batteries face challenges in achieving low battery resistance and improved peeling strength, which are crucial for enhanced producibility and performance.
Innovation Solution
A positive electrode active material with secondary particles that have specific pore distributions, as determined by the mercury intrusion method, and a composition formula Li[Lix(Ni(1-y-z-w)CoyMnzMw)1-x]O2, where M represents certain elements, with controlled tap density, average secondary particle diameter, and surface area ratios, facilitating better adhesion and electrolyte penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive electrode active material is designed to improve battery capacitance performance, then battery performance is enhanced, but battery resistance increases and producibility deteriorates
Solution Approach 1:
The patent applies porous materials by designing the positive electrode active material with a specific pore distribution structure. The material contains pores with a peak pore radius of 0.003 μm to 0.03 μm, and the total pore volume is controlled within 0.03 mL/g to 0.30 mL/g. This porous structure allows electrolyte penetration while maintaining low resistance, resolving the contradiction between capacitance enhancement and resistance reduction.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the pore distribution parameters of the positive electrode active material. Specifically, the peak pore radius is set to 0.003 μm to 0.03 μm and total pore volume to 0.03 mL/g to 0.30 mL/g. These parameter optimizations enable the material to achieve both high capacitance and low resistance, improving battery performance without increasing resistance.
2Quantity of substance
If the positive electrode active material structure is optimized for performance, then battery capacitance improves, but peeling strength decreases and producibility worsens
Solution Approach 1:
The patent utilizes porous materials with a controlled pore distribution (peak pore radius 0.003 μm to 0.03 μm, total pore volume 0.03 mL/g to 0.30 mL/g) in the positive electrode active material. This porous structure enhances capacitance while the controlled pore size and distribution maintain adequate peeling strength, preventing powder from falling and adhering to rolls during manufacturing.
Solution Approach 2:
The patent applies parameter changes by optimizing the pore distribution parameters of the positive electrode active material. The peak pore radius is controlled within 0.003 μm to 0.03 μm and total pore volume within 0.03 mL/g to 0.30 mL/g. These parameter optimizations enable the material to achieve high capacitance while maintaining sufficient peeling strength for improved producibility.
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 results in a positive electrode active material with low battery resistance and improved peeling strength, leading to enhanced performance and stability in lithium secondary batteries.
Implementation Method 1
primary particles capable of being doped and de-doped with lithium ions
Implementation Method 2
pore distribution obtained by a mercury intrusion method
Data Source
AI summary
The present invention provides a positive electrode active material for lithium secondary batteries including: secondary particles obtained by aggregating primary particles capable of being doped and de-doped with lithium ions, in which the secondary particles have pores, and pore distribution obtained by a mercury intrusion method satisfies requirements (1) and (2) below:(1) pores that are present in any one or both of the secondary particles or spaces between the secondary particles have a pore peak within a range of a pore radius of equal to or greater than 10 nm and equal to or less than 200 nm; and(2) a total surface area of pores that have pore radii of equal to or greater than 100 nm and equal to or less than 10 μm among the pores that are present in any one or both of the secondary particles or spaces between the secondary particles is less than 1.1 m2/g.