Solid Electrolyte Membrane Binder for Flexible Li-Ion Separators
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Solution Overview
Problem
Conventional solid electrolyte separators in solid-state batteries are rigid and inflexible, making them unsuitable for large-scale manufacturing and incorporation into wound electrochemical cells, while attempts to increase flexibility often compromise ionic conductivity.
Innovation Solution
A solid electrolyte separator membrane is created using solid electrolyte particles bound together by an ion conducting polymer electrolyte and mechanically interlocked by chopped nonpolar or polar nanofibers, which enhance mechanical strength and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid electrolyte particles are bound together using conventional rigid binders, then mechanical strength is improved, but flexibility deteriorates
Solution Approach 1:
The patent employs a composite binder system combining ion-conducting polymer electrolyte with chopped nanofibers (both polar and nonpolar types). This composite approach allows the polymer to provide ionic conductivity and flexibility while the nanofibers contribute mechanical strength through mechanical interlocking, thus resolving the contradiction between mechanical strength and flexibility.
Solution Approach 2:
The patent changes the physical and chemical parameters of the binder system by using a polymer electrolyte with specific glass transition temperature characteristics and incorporating nanofibers with controlled aspect ratios and surface treatments. These parameter changes enable the binder to simultaneously achieve flexibility (through polymer chain mobility) and mechanical strength (through nanofiber reinforcement).
2Ease of manufacture
If flexibility of solid electrolyte separator is increased, then ease of manufacture is improved, but ionic conductivity deteriorates
Solution Approach 1:
The ion-conducting polymer electrolyte binder serves dual functions: it provides flexibility to the separator for ease of manufacture and handling, while simultaneously maintaining ionic conductivity through its inherent ion-conducting properties. The chopped nanofibers reinforce this effect by providing mechanical strength without blocking ion transport pathways.
Solution Approach 2:
The polymer electrolyte acts as an intermediary material between solid electrolyte particles, providing both mechanical flexibility and ionic conduction pathways. This intermediary role allows the separator to be flexible enough for manufacturing while maintaining sufficient ionic conductivity for battery operation.
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 proposed solid electrolyte separator achieves high ionic conductivity (greater than 1 mS/cm) and superior mechanical properties, including flexibility and strength, while simplifying battery packaging and reducing manufacturing complexities.
Implementation Method 1
solid electrolyte particles that are bound together by an ion conducting polymer electrolyte
Implementation Method 2
mechanically interlocked by chopped nonpolar nanofibers
Implementation Method 3
chopped polar polymer nanofibers that mechanically interlock the solid electrolyte particles together and contain polar functional groups, which generate intermolecular forces that attract the solid electrolyte particles
Data Source
AI summary
A solid electrolyte separator sheet for a solid-state lithium-ion battery is provided. The solid electrolyte separator sheet may comprise a membrane including solid electrolyte particles, an ion conducting polymer electrolyte binder, and a filament-type binder comprising chopped nanofibers. The ion conducting polymer electrolyte may include in situ formed, polyethylene-oxide-like polymer electrolyte.