Polymaleimide Polymer Electrolyte for Conductivity and Voltage Stability
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Solution Overview
Problem
Current polymer electrolytes for batteries suffer from low ionic conductivity, instability at high voltages, mechanical weakness, and risk of polarization, leading to reduced battery performance and safety concerns.
Innovation Solution
A polymer electrolyte comprising a polymaleimide copolymer with specific repeat units and a thiol-ene reaction process that allows for solvent-free production, enhancing ionic conductivity, mechanical stability, and high voltage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If gel polymer electrolytes with cross-linked polymer structure are used, then structural and mechanical stability is improved, but ionic conductivity decreases
Solution Approach 1:
The patent introduces phase-separated structures where conductive domains (rich in plasticizer and lithium salt) are embedded within the cross-linked polymer matrix. These localized regions provide high ionic conductivity pathways while the surrounding cross-linked structure maintains mechanical integrity, thus resolving the contradiction between structural stability and ionic conductivity.
Solution Approach 2:
The electrolyte is designed as a composite system combining cross-linked polymer networks with plasticizer and lithium salt components. This composite structure allows the cross-linked polymer to provide mechanical strength while the plasticizer and salt phases provide ionic conduction pathways, achieving both structural stability and high ionic conductivity simultaneously.
2Reliability
If polyether groups are used in cross-linked polymer network, then ionic conductivity is improved, but voltage stability deteriorates
Solution Approach 1:
The patent creates localized conductive domains where polyether groups are concentrated, providing high ionic conductivity in specific regions. The bulk polymer matrix uses alternative chemistries (such as carbonates or ethers with better voltage stability) that maintain electrochemical stability at high voltages, thus resolving the contradiction between ionic conductivity and voltage stability.
Solution Approach 2:
The electrolyte combines multiple polymer chemistries and plasticizer types within a single cross-linked network. This merging of different material systems allows the polyether components to provide ionic conductivity while other components (such as cyclic carbonates or chain carbonates) provide voltage stability, achieving both properties simultaneously through synergistic combination.
3Reliability
If dual-ion conductive salt is used, then ionic conductivity is improved, but polarization risk increases
Solution Approach 1:
The patent optimizes the lithium salt concentration and composition within the electrolyte to achieve high ionic conductivity while maintaining a high lithium transference number. By carefully controlling the salt-to-plasticizer ratio and selecting appropriate lithium salts (such as LiPF6, LiBF4, or LiTFSI), the electrolyte achieves fast ion transport with minimal polarization, resolving the contradiction between conductivity and polarization resistance.
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 polymer electrolyte achieves high ionic conductivity, thermal stability, and mechanical robustness, reducing polarization and extending battery life with improved performance under repeated charging/discharging cycles.
Implementation Method 1
a thiol-ene reaction process that allows for solvent-free production
Implementation Method 2
high ionic conductivity
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3
AI summary
The present invention relates to a polymer electrolyte for a battery cell comprising a polymaleimide copolymer comprising i) first polymaleimide repeat units according R3(Q)µ, wherein R3, individually, is C(H)h(CxH2x+1)i((CH2)ψ)j(CH2OC(O)(CH2)σ)k or a polyether, wherein i is between 0 and 2; j and k, individually, are between 0 and 4; h is 4 - i - j - k; the sum of h and i is between 0 and 2; x is between 1 and 6; ψ is between 1 and 10; and σ is between 1 and 20; µ, individually, is at least 2; Q, individually, is according to formula (I): wherein R2, individually, is C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkynyl or aryl; R4, individually, is H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkynyl; Q is covalently bound to R3 via the sulphur atom of Q; ii) second polymaleimide repeat units according to formula (II) wherein R1, individually, is H, C1-C16 alkyl, C2-C16 alkenyl, C2-C16 alkynyl; m, individually, is 1 to 5; M+ is independently an alkali metal ion; X, individually, is H, F, C1-C16 alkyl, C1-C16 fluoroalkyl; wherein the first polymaleimide repeat units and the second polymaleimide repeat units are covalently bonded to one another.