Polymer-Modified Porous Separator for Battery Self-Discharge Control
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Solution Overview
Problem
Existing membrane electrodes in active ion batteries suffer from significant self-discharge and insufficient insulation, leading to reduced cycle performance and safety concerns due to thermal contraction and increased internal resistance.
Innovation Solution
A polymer-modified porous material with surface groups containing linking and adhesive units is used to form a separator, creating a tightly interlaced organic polymer network that enhances insulation, adhesion, and electrolyte infiltration, thereby preventing self-discharge and ensuring long-term cycle stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an inorganic coating layer is coated on the surface of the electrode to form an inorganic separator, then the thermal stability of the separator is improved, but the insulating property becomes insufficient resulting in significant self-discharge
Solution Approach 1:
The patent applies composite materials by combining inorganic porous material particles with organic polymer materials to form a composite separator. The inorganic particles provide thermal stability and high-temperature resistance, while the organic polymer matrix provides insulation and prevents self-discharge. This composite structure resolves the contradiction between thermal stability and insulating properties by integrating the advantages of both material types.
Solution Approach 2:
The patent changes the chemical composition parameters of the separator by incorporating specific organic groups (carboxyl, hydroxyl, amine, or isocyanate groups) into the polymer matrix. These functional groups enhance the insulating properties while maintaining thermal stability. The parameter change from pure inorganic coating to organic-inorganic composite with specific functional groups resolves the self-discharge issue.
2Temperature
If ceramic coating is applied to improve heat resistance, then the thermal stability is enhanced, but the internal resistance increases limiting electrical performance
Solution Approach 1:
The patent utilizes porous inorganic material particles with controlled pore structures that allow efficient ion transport. The porous structure maintains low internal resistance by providing continuous pathways for ion conduction, while the inorganic material itself provides the required heat resistance. This resolves the contradiction between heat resistance and electrical performance.
Solution Approach 2:
The patent applies local quality by distributing inorganic porous particles throughout the polymer matrix rather than creating a continuous coating layer. This localized distribution allows the inorganic particles to provide thermal stability where needed while the polymer matrix maintains overall ion conductivity and low resistance, preventing the increase in internal resistance.
3Strength
If polyolefin-based separator material is used, then sufficient mechanical strength and chemical stability are provided, but thermal contraction at high temperatures causes short-circuit and safety accidents
Solution Approach 1:
The patent creates a composite structure where inorganic porous particles are embedded in an organic polymer matrix. The inorganic component provides dimensional stability at high temperatures and prevents thermal contraction, while the polymer matrix maintains mechanical strength and flexibility. This composite approach resolves the contradiction between mechanical strength and thermal stability.
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 polymer-modified porous material effectively reduces self-discharge, improves electrochemical performance, and ensures long-term cycle stability and safety by forming a robust insulating barrier and facilitating electrolyte infiltration, while maintaining sufficient adhesion to the pole plate.
Implementation Method 1
the porous material may spread well in the coating to form a tightly interlaced organic polymer network, which may improve the insulation of the separator and prevent the occurrence of self-discharge
Implementation Method 2
since a large number of organic groups are grafted on the surface of the porous material, the contact effect of the separator formed of the polymer-modified porous material with the electrolyte is increased, facilitating the infiltration of the electrolyte
Implementation Method 3
by controlling the ratio of the adhesive group and the linking group, not only the barrier effect of the porous material on the electron conduction, but also the sufficient adhesion between the separator formed by the polymer-modified porous material and the pole plate can be ensured
Data Source
AI summary
A polymer-modified porous material, a membrane electrode, and applications thereof are disclosed. The polymer-modified porous material includes a porous material and a plurality of surface groups attached to the porous material; each of the surface groups includes a linking group and an adhesive group that are attached in sequence; the linking group has a structure represented by a structural unit I, wherein represents that O is linked to the porous material; the number of the structural units I in each of the surface groups is independent from each other; the total number n of moles of the structural units I in the polymer-modified porous material is 1,000-10,000; and the total number m of moles of the adhesive groups is 10-1,000, and n/m=10-1,000. The problem of serious self-discharge of existing membrane electrodes is alleviated.