Polycarbonate sIPN Solid Electrolyte for Stable Alkali-Metal Batteries
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Solution Overview
Problem
Current solid electrolytes, particularly those based on polyethylene oxide (PEO), face challenges with stability and reproducibility during charge/discharge cycles, especially at higher voltages and lower temperatures, leading to inhomogeneous Li-ion transport and potential short circuits.
Innovation Solution
A solid electrolyte comprising a mixture of two different alkali metal conductive salts and a semi-interpenetrating network (sIPN) made of cross-linked and non-cross-linked polymers, with the sIPN consisting of 50-80% non-crosslinked PEO or its derivatives and 10-50% crosslinked polycarbonate monomers, enhancing mechanical and electrical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PEO-based solid electrolyte is used, then ease of manufacture and low cost are achieved, but mechanical stability and reproducibility deteriorate during charge/discharge cycles
Solution Approach 1:
The patent applies composite materials by combining PEO with crosslinkable polycarbonate monomers to form a semi-interpenetrating polymer network (sIPN). This composite structure integrates the ease of processing of PEO with the mechanical stability of crosslinked polycarbonate, resolving the contradiction between manufacturability and cycle stability.
Solution Approach 2:
The patent changes the structural parameters of the electrolyte by introducing crosslinkable functional groups (acrylic, methacrylic, epoxy, vinyl, or isocyanide groups) on the polycarbonate monomers. This parameter change enables crosslinking that enhances mechanical stability while maintaining the base polymer's processability.
2Ease of manufacture
If PEO-based solid electrolyte is used, then low cost and ease of processing are achieved, but mechanical strength and structural stability worsen
Solution Approach 1:
The patent modifies the molecular structure parameters by incorporating crosslinkable functional groups on polycarbonate monomers that can form crosslinked networks. This structural parameter change enhances mechanical strength while the base PEO matrix maintains ease of processing.
Solution Approach 2:
The semi-interpenetrating network combines two polymer systems: PEO providing processability and crosslinked polycarbonate providing mechanical strength. This composite approach resolves the contradiction between ease of processing and mechanical strength.
3Quantity of substance
If PEO is used as electrolyte, then low cost and availability are achieved, but inhomogeneous Li-ion transport occurs at high voltage electrodes
Solution Approach 1:
The patent uses composite materials (sIPN of PEO and polycarbonate) to create a more homogeneous electrolyte matrix that enables uniform Li-ion transport across high voltage electrodes, resolving the inhomogeneity problem while maintaining availability through the use of common polymer components.
4Adaptability or versatility
If operating temperature is reduced, then application range is expanded, but capacity loss and performance deterioration occur
Solution Approach 1:
The patent changes the thermal parameters of the electrolyte through crosslinking, which enhances the structural stability and maintains ion conductivity at lower temperatures. The crosslinked network prevents excessive chain mobility at low temperatures, maintaining capacity retention while expanding the operating temperature range.
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 electrolyte structure significantly improves mechanical stability and reproducibility, extending the service life and allowing operation at lower temperatures without capacity loss, with the dual salt and polycarbonate network providing homogeneous mixing and stable ion coordination.
Implementation Method 1
a semi-interpenetrating network (sIPN) made of a crosslinked and a non-crosslinked polymer
Implementation Method 2
with the dual salt and polycarbonate network providing homogeneous mixing and stable ion coordination
Implementation Method 3
a solid electrolyte for an alkali metal solid-state battery, wherein the solid electrolyte comprises a mixture of two different alkali metal conducting salts
Data Source
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AI summary
The present invention relates to solid-state electrolyte for an alkali-metal solid-state battery, the solid-state electrolyte comprising a mixture of two different alkali-metal conductive salts and a semi-interpenetrating network (sIPN) formed from a crosslinked and an uncrosslinked polymer, the semi-interpenetrating network comprising greater than or equal to 50 wt.% and less than or equal to 80 wt.% of an uncrosslinked polymer chosen from the group selected of polyethylene oxide (PEO), polycarbonate (PC), polycaprolactone (PCL), chain-modified derivatives of these polymers, or mixtures of at least two components thereof; and comprising greater than or equal to 10 wt.% and less than or equal to 50 wt.% of a polycarbonate formed from crosslinkable polyalkyl-carbonate monomers with a carbon number of greater than or equal to 2 and less than or equal to 15 based on the individual monomer as crosslinked polymer, the individual polyalkyl-carbonate monomer can be substituted or unsubstituted and comprising two crosslinkable groups chosen from the group consisting of acryl, methacryl, epoxy, vinyl, isocyanide or mixtures of two different groups thereof. The present invention furthermore relates to an alkali-metal battery comprising a solid-state electrolyte according to the invention.