Crystalline Zwitterionic Solid Electrolytes for High Ion Conductivity
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Solution Overview
Problem
Current solid polymer electrolytes face challenges in achieving high ionic conductivities across a wide temperature range without compromising mechanical properties, as ion transport is strongly coupled with polymer segmental relaxation rates, limiting their performance in next-generation batteries.
Innovation Solution
The development of ionic-liquid inspired crystalline zwitterionic (ZI) solid electrolytes that decouple ion transport from the fluidity of the matrix, incorporating zwitterionic compounds and electrolyte salts to create a solid with crystalline and amorphous regions, allowing for superionic performance and mechanical robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid polymer electrolytes are used to ensure mechanical robustness, then mechanical properties are improved, but ion conductivity deteriorates due to strong coupling between polymer segmental relaxation and ion mobilities
Solution Approach 1:
The electrolyte is segmented into distinct crystalline domains embedded in an amorphous polymer matrix. The crystalline regions provide ion conduction pathways with high conductivity, while the amorphous matrix maintains mechanical flexibility and processability. This spatial segmentation allows independent optimization of conductive and mechanical functions.
Solution Approach 2:
The invention creates a composite material system combining crystalline zwitterionic compounds with amorphous polymer electrolyte matrix. The crystalline phase contributes high ion conductivity through ordered pathways, while the amorphous phase provides mechanical robustness and processability, achieving synergistic properties not attainable with single-phase materials.
2Reliability
If conventional solid polymer electrolytes are designed to achieve high ion conductivity, then ion mobility is improved, but the operating temperature range is limited due to coupling with polymer relaxation rates
Solution Approach 1:
The invention changes the fundamental conduction mechanism parameter from polymer-relaxation-dependent to crystal-structure-dependent ion transport. By introducing crystalline phases with specific lattice structures and void spaces, the ion conductivity becomes determined by crystal parameters rather than polymer relaxation rates, enabling stable performance across wide temperature ranges.
Solution Approach 2:
The invention utilizes phase transitions by forming crystalline regions within the polymer electrolyte. The crystalline phase remains stable across a broad temperature range, providing consistent ion conduction pathways unlike the amorphous polymer matrix whose properties change dramatically with temperature. This phase separation enables temperature-independent ion transport.
3Reliability
If inorganic solid-state electrolytes are used to achieve superionic performance, then ion conductivity is improved, but processability and ductility deteriorate
Solution Approach 1:
The invention applies local quality by creating localized crystalline regions with superionic conductive properties within a ductile polymeric matrix. The crystalline domains provide high conductivity where needed, while the surrounding amorphous polymer provides processability and mechanical flexibility, allowing the material to be processed like conventional polymers despite containing high-performance inorganic-like conductive phases.
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
These electrolytes exhibit high ion conductivity (at least 10−4 S/cm at 50°C) and transport number (at least 0.5) while maintaining mechanical properties, comparable to inorganic solid-state electrolytes and processable like traditional polymeric electrolytes.
Implementation Method 1
the solid conducts the alkali metal ions obtained from the salt and the zwitterionic compounds each include zero or more amorphous regions and one or more crystalline regions
Implementation Method 2
one or more crystalline regions characterized by: a presence of Bragg diffraction peaks in an X-ray diffraction measurement of the solid
Data Source
AI summary
A solid electrolyte including zwitterionic compounds comprising zwitterionic molecules and/or charge neutral polymers with zwitterion pendants. A salt is distributed through the solid such that the solid conducts alkali metal ions obtained from the salt and the zwitterionic compounds each include zero or more amorphous regions and one or more crystalline regions characterized by (1) a presence of Bragg diffraction peaks in an X-ray diffraction measurement of the solid; and (2) the solid having an ion conductivity of at least 10−4 S/cm at a temperature of 50 degrees Celsius when a transport number for the alkali metal ions is at least 0.5 and a molar ratio of the salt to the zwitterionic units is 0.9. The electrolyte exhibits surprisingly high alkali metal ion conductivity and linear elastic modulus over a wide range of practically useful temperatures.