Gel Composite Electrolyte Membrane for Higher Li+ Conductivity
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Solution Overview
Problem
PEO-based polymer electrolytes in lithium batteries suffer from low room-temperature ionic conductivity and low Li+ transference number, and existing solutions like incorporating ceramic fillers or infusing liquid plasticizers do not effectively address these issues, leading to high interfacial resistance and manufacturing costs.
Innovation Solution
A gel composite electrolyte membrane is developed using a crosslinked PEO network with a Li salt, ceramic fillers, and a plasticizer, which synergistically improves Li+ transference number and conductivity, while maintaining mechanical stability and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic fillers are incorporated into polymer electrolyte matrix to increase ionic conductivity, then ionic conductivity is improved, but interfacial resistance between polymer and ceramic electrolytes increases, preventing effective ion transport
Solution Approach 1:
The patent applies local quality by creating distinct regions with different properties: a polymer-rich interfacial layer at the ceramic-polymer boundary to reduce interfacial resistance, while maintaining ceramic filler distribution for ionic conductivity. This localized variation in composition optimizes both ion transport through the ceramic phase and reduces resistance at the interface.
Solution Approach 2:
The patent uses composite materials by combining polymer electrolyte matrix with ceramic fillers to create a composite structure that leverages the high ionic conductivity of ceramics while using the polymer matrix to provide flexibility and processability. The composite structure enables synergistic performance beyond what either material could achieve alone.
2Ease of manufacture
If PEO based polymer electrolyte is used in lithium batteries, then ease of manufacture is improved, but room temperature ionic conductivity and Li+ transference number are low
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing and characterizing the polymer matrix and ceramic filler components before final assembly. The polymer electrolyte matrix is prepared with controlled molecular weight and functional groups, and ceramic fillers are pre-characterized for size and surface properties. This preliminary preparation ensures consistent performance while maintaining ease of manufacture through standardized procedures.
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 gel composite electrolyte exhibits improved Li+ conductivity, lower interfacial impedance, and enhanced cycling performance, with a 2-fold increase in Li+ transference number and conductivity, and better handleability, without compromising mechanical properties.
Implementation Method 1
The crosslinked PEO network serves as a host for the plasticizer, thereby avoiding leakage and reducing the flammability of the organic plasticizers
Implementation Method 2
A polymer-ceramic composite in which highly conductive ceramic fillers are incorporated into a polymer electrolyte matrix has been considered as a solution to increase ionic conductivity
Implementation Method 3
Another solution to polymer electrolytes' low room temperature ionic conductivity is to infuse a liquid plasticizer into the polymer electrolyte to form a gel polymer electrolyte
Data Source
AI summary
An improved gel composite electrolyte membrane and a method of its manufacture are provided. The method includes mixing polymer precursors, a lithium salt, and a ceramic filler in a vessel to form a mixture. The mixture is cast on a preheated substrate and cured to form a crosslinked composite electrolyte membrane. The composite electrolyte membrane is plasticized by immersing the composite electrolyte in a plasticizer to obtain a gel composite electrolyte membrane. The addition of a plasticizer and a ceramic filler synergistically and simultaneously act to improve the Li+ transference number and Li+ conductivity of the resulting composite electrolyte, exhibiting high ionic conductivity and mechanical stability as well improved cycling performance. The gel composite electrolyte membrane is particularly suitable for, but not limited to, lithium metal batteries.