UV-Cured SIPN Electrolyte for Low-Impedance Lithium-Ion Conduction
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Solution Overview
Problem
Traditional polyethylene oxide electrolytes in lithium-ion batteries suffer from high interfacial impedance and low ionic conductivity at room temperature, limiting their rate and cycle performances.
Innovation Solution
A semi-interpenetrating polymer network (SIPN) electrolyte is developed using poly(vinylidene fluoride-co-hexafluoropropylene), a diallyl compound, a crosslinking agent, a plasticizer, and a photoinitiator, formed through a UV-curing process to enhance mechanical properties and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyethylene oxide electrolyte is used, then the electrolyte provides basic ionic conduction function, but the ionic conductivity is low and interfacial impedance is high at room temperature
Solution Approach 1:
The patent creates a composite electrolyte system by integrating PVdF-HFP polymer matrix with PEGDMA crosslinked network and lithium salt. This composite structure combines the mechanical stability of PVdF-HFP with the ionic conductivity enhancement from PEGDMA, achieving both high ionic conductivity (2.45×10⁻⁴ S·cm⁻¹) and excellent rate performance without sacrificing structural integrity
Solution Approach 2:
The patent optimizes multiple parameters including the mass ratio of PVdF-HFP to PEGDMA (10-40):(30-70), crosslinking agent concentration (1-5%), and lithium salt content (1:(2-10)). These parameter optimizations enable the electrolyte to achieve peak ionic conductivity and rate performance by tuning the balance between polymer chain mobility and crosslinking density
2Object-affected harmful factors
If polymer electrolyte is used to replace organic electrolyte, then safety performance is improved, but the mechanical properties and flexibility need enhancement
Solution Approach 1:
The patent introduces localized crosslinked regions within the polymer matrix through PEGDMA network formation. These crosslinked zones provide localized mechanical reinforcement and structural stability, while the bulk polymer matrix maintains its flexibility and ion-conducting channels, achieving both strength and flexibility requirements
Solution Approach 2:
The PEGDMA crosslinked network acts as an intermediary structure between the PVdF-HFP polymer chains. It provides mechanical support and structural framework while allowing lithium ion transport through the network, effectively mediating between mechanical strength requirements and ionic conductivity needs
3Stability of the object's composition
If crosslinked network is introduced to enhance mechanical properties, then the structural stability is improved, but the ionic conductivity may be reduced due to restricted polymer chain mobility
Solution Approach 1:
The crosslinked PEGDMA network creates a porous or semi-porous structure within the PVdF-HFP matrix. These pores and channels serve as pathways for lithium ion transport, maintaining high ionic conductivity while the crosslinked framework provides structural stability. The porosity prevents excessive restriction of ion mobility despite the presence of crosslinks
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 SIPN electrolyte achieves excellent rate performance and stable cycle performance, with an ion conductivity of 2.45×10⁻⁴ S·cm⁻¹ at room temperature and a specific discharge capacity of up to 160 mA·h·g⁻¹ at 0.1 C, demonstrating improved compatibility and safety.
Implementation Method 1
forming a film from the precursor solution, and subjecting the film to ultraviolet irradiation to obtain the SIPN electrolyte
Data Source
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AI summary
The present disclosure relates to the technical field of solid polymer electrolytes, in particular to a semi-interpenetrating polymer network (SIPN) electrolyte and a preparation method and use thereof. The present disclosure provides an SIPN electrolyte, including the following raw materials: poly(vinylidene fluoride-co-hexafluoropropylene), a diallyl compound, a crosslinking agent, a plasticizer, a photoinitiator , and a lithium salt; where the poly(vinylidene fluoride-co-hexafluoropropylene), the diallyl compound, the crosslinking agent, the plasticizer, and the photoinitiator are at a mass ratio of (10-40):(30-70):(1-5):(1-20):(2-10); and the lithium salt and the SIPN electrolyte are at a mass ratio of 1:(1-10). The SIPN electrolyte has an excellent rate performance and a stable cycle performance.