Interpenetrating Polymer Network Solid Electrolyte for Lithium Batteries
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Solution Overview
Problem
Solid polymer electrolytes with high crystallization degrees and low ion conductivities and thermal stabilities due to the use of polymers with specific segments, which hinder their application in lithium-based batteries.
Innovation Solution
An interpenetrating polymer network (IPN) is formed by polymerizing a first monomer with a second monomer under an initiator, with specific unsaturated groups and molecular weights, and a method involving mixing and polymerizing these monomers with a weight ratio of the first monomer being less than or equal to 50%, using either UV or thermal initiation to create a branched structure with improved thermal and electrochemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymers with specific segments are used as solid electrolyte matrixes, then compatibility with lithium salts is improved, but crystallization degree increases leading to low ion conductivity and poor thermal stability
Solution Approach 1:
The patent uses an interpenetrating polymer network (IPN) structure combining two different polymer segments: PEG-diA (polyethylene glycol dimethacrylate) and PEG-mA (polyethylene glycol monoacrylate). This composite structure allows the system to benefit from both segments' compatibility with lithium salts while the IPN configuration suppresses crystallization through its complex intertwined architecture, achieving both reliability and compositional stability.
Solution Approach 2:
The patent applies local quality by creating regions with different polymer densities and configurations within the IPN structure. The PEG-diA segments provide lithium salt compatibility in certain regions, while the PEG-mA segments provide amorphous stability in other regions. This spatial differentiation of material properties allows simultaneous optimization of both compatibility and crystallization resistance.
2Reliability
If polymers with specific segments are used as solid electrolyte matrixes, then compatibility with lithium salts is improved, but thermal stability deteriorates
Solution Approach 1:
The IPN composite structure combines PEG-diA and PEG-mA segments that work synergistically: PEG-diA provides lithium salt compatibility while PEG-mA contributes thermal stability through its amorphous nature. The crosslinked network structure formed by the IPN further enhances thermal resistance without compromising the compatibility benefits of either segment.
Solution Approach 2:
The patent changes the molecular weight and structural parameters of the polymer segments to optimize performance. By selecting specific molecular weights for PEG-diA and PEG-mA and controlling their weight ratio (first monomer ≤50% of second monomer), the patent achieves optimal balance between lithium salt compatibility and thermal stability while maintaining amorphous structure.
3Reliability
If polymers with specific segments are used as solid electrolyte matrixes, then compatibility with lithium salts is improved, but ion conductivity deteriorates
Solution Approach 1:
The IPN composite structure addresses this contradiction by creating a dual-function material system. The PEG-diA segments ensure good lithium salt compatibility and ionic pathways, while the PEG-mA segments maintain amorphous structure that facilitates ion transport. The crosslinked network provides mechanical integrity while the interpenetrating architecture creates multiple ion conduction channels.
Solution Approach 2:
The patent creates local quality variations within the IPN structure where PEG-diA-rich regions provide lithium salt dissolution and PEG-mA-rich regions provide amorphous ion transport pathways. This spatial differentiation of functional properties allows simultaneous optimization of compatibility and ion conductivity.
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 IPN achieves high thermal stability, low crystallization degree, and excellent ionic conductivity, making it suitable for use in solid polymer electrolytes, enhancing the performance of lithium-based batteries with improved safety and electrochemical stability.
Implementation Method 1
polymerizing a first monomer with a second monomer under an initiator... using either UV or thermal initiation to create a branched structure
Implementation Method 2
using either UV or thermal initiation to create a branched structure
Data Source
AI summary
An interpenetrating polymer network includes CH2—CH2—On segments, and is formed by polymerizing a first monomer R1—OCH2—CH2—OnR2 with a second monomer R3—OCH2—CH2—OmR4 under an initiator. Each “R1”, “R2” and “R3” includes —C═C— group or —C≡C— group. The “R4” includes an alkyl group or a hydrogen atom. The “m” and “n” are integer. Molecular weights of the first monomer and the second monomer are more than or equal to 100, and less than or equal to 800. The first monomer is less than or equal to 50% of the second monomer by weight. A method for making the interpenetrating polymer network is also provided.