Zeolite-Polyimide Separator Membrane for Heat-Resistant Electrolyte Wetting
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Solution Overview
Problem
Current polyolefin separators for lithium ion batteries have insufficient wetting ability and poor heat resistance, making them unsuitable for high-temperature environments and requiring additional inorganic nano-particles to improve electrolyte wettability.
Innovation Solution
A zeolite/polyimide composite membrane is prepared through non-solvent induced phase separation, combining the high temperature resistance of polyimide with the electrolyte-philic properties of zeolite, using a method involving zeolite-doped polyamic acid precursor synthesis, casting, and thermal imidization to achieve a membrane with small pore size and uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyolefin separator is used, then production cost is low and mechanical strength is good, but electrolyte wettability is insufficient and heat resistance is poor
Solution Approach 1:
The patent creates a composite membrane structure by integrating zeolite particles into the polyimide matrix. The zeolite provides electrolyte wettability while polyimide provides mechanical strength and heat resistance, resolving the contradiction between low cost/good mechanics and good wettability through material composition rather than additive modification
2Ease of manufacture
If polyolefin separator is used, then production cost is low and mechanical strength is good, but heat resistance is poor
Solution Approach 1:
The composite of zeolite and polyimide creates a material that maintains structural integrity at high temperatures. The polyimide matrix provides inherent heat resistance (stable up to 300°C) while zeolite particles maintain their crystalline structure, preventing membrane collapse and maintaining separation function under thermal stress
3Reliability
If inorganic nano-particles are added to improve electrolyte wettability, then electrolyte wettability is improved, but device complexity increases
Solution Approach 1:
The patent combines zeolite doping with polyimide membrane formation into a single integrated process. The zeolite-doped polyamic acid precursor solution is cast and processed through non-solvent induced phase separation to directly form the composite membrane, eliminating separate doping steps and reducing process complexity
4Device complexity
If non-solvent induced phase separation is used, then manufacturing complexity is reduced, but pore size uniformity is poor
Solution Approach 1:
The patent optimizes parameters including humidity (70-90%), temperature gradients during imidization, and zeolite particle size (0.5-5 μm) to control phase separation kinetics. These parameter adjustments ensure uniform nucleation and growth of pores while maintaining the simplicity of the non-solvent induced phase separation method
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 zeolite/polyimide composite membrane enhances the safety and electrochemical performance of lithium ion batteries by improving electrolyte wettability and ionic conductivity, maintaining performance over multiple charge-discharge cycles.
Implementation Method 1
obtaining a zeolite/polyamic acid composite porous membrane by non-solvent induced phase separation
Implementation Method 2
synthesizing a zeolite-doped polyamic acid precursor casting solution by condensation polymerization synthesis
Implementation Method 3
obtaining a zeolite/polyimide composite membrane by performing thermal imidization on the zeolite/polyamic acid composite porous membrane through gradient heating
Implementation Method 4
Zeolite has a unique channel structure, a high surface area and a strong Lewis acidity, making it one of candidate inorganic nano-materials for fillers of the lithium ion battery separators
Data Source
AI summary
A preparation method of a zeolite/polyimide composite membrane includes: synthesizing a zeolite-doped polyamic acid precursor casting solution by condensation polymerization synthesis; coating a substrate with the obtained casting solution, and obtaining a zeolite/polyamic acid composite porous membrane by non-solvent induced phase separation; and obtaining the zeolite/polyimide composite membrane by performing thermal imidization on the zeolite/polyamic acid composite porous membrane through gradient heating.