Positive-Electrode Active Material Pore Size for Li-Ion Capacity
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Solution Overview
Problem
Existing lithium-ion secondary batteries face challenges in achieving sufficient capacity and battery characteristics, particularly when using positive-electrode active materials with small pore sizes that hinder electrolyte penetration and reduce contact area.
Innovation Solution
A positive-electrode active material with an average pore size of 0.2 μm to 1.0 μm, measured in the range of 0.0036 μm to 400 μm, is developed to enhance the contact area with the electrolyte, thereby improving battery characteristics such as charge and discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pore size of the positive-electrode active material is reduced to increase contact area, then the contact area with electrolyte increases, but the electrolyte penetration and capacity are hindered
Solution Approach 1:
The patent applies porous materials by controlling the pore size of the positive-electrode active material to be 0.003 μm or more, ensuring that the material has sufficient porosity to allow electrolyte penetration while maintaining a large contact area. This resolves the contradiction by using the porous structure to simultaneously achieve both large surface area and adequate substance transport.
2Quantity of substance
If the pore size of the positive-electrode active material is increased to improve electrolyte penetration, then the capacity increases, but the contact area with electrolyte is reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pore size parameter within the range of 0.003 μm or more (avoiding smaller sizes). This parameter optimization ensures that the pores are large enough to facilitate electrolyte penetration and capacity while maintaining sufficient surface area for contact, thus resolving the contradiction between pore size and contact area.
3Area of stationary object
If the positive-electrode active material uses smaller particles to increase surface area, then the contact area increases, but the structural stability and cycle characteristics deteriorate
Solution Approach 1:
The patent applies porous materials with controlled pore sizes of 0.003 μm or more, which provides a balance between surface area and structural stability. The porous structure increases surface area for contact while the controlled pore size prevents excessive fragmentation and maintains structural integrity during cycling, thus improving both contact area and cycle 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 optimized pore size range allows for increased electrolyte penetration and a larger contact area, leading to improved charge and discharge capacity and efficiency of lithium-ion secondary batteries.
Implementation Method 1
materials capable of de-intercalating and intercalating lithium are used
Implementation Method 2
particles of a porous positive-electrode active material having a uniform pore on the surface
Data Source
AI summary
A positive-electrode active material for a lithium-ion secondary battery, wherein an average pore size of the positive-electrode active material is 0.2 μm to 1.0 μm when a pore size is measured in a range of 0.0036 μm to 400 μm.