Composite Polymer Electrolyte Membrane for Safer Solid-State Li-Ion Cells
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Solution Overview
Problem
Existing solid-state electrolytes in lithium ion batteries suffer from poor lithium ion conductivity and issues such as short circuits and electrolyte leakage, which are not adequately addressed by current dual-layer polymer electrolytes.
Innovation Solution
A solid-state composite polymer electrolyte membrane comprising a solid-state electrolyte layer with poly(vinylidene fluoride-co-hexafluoropropylene), lithium bis(trifluoromethanesulfonyl)imide, succinonitrile, and aluminum-doped lithium lanthanum zirconium oxide, and a first cured electrolyte layer formed by polymerizing an acrylic material with lithium bis(trifluoromethanesulfonyl)imide and succinonitrile, enhancing lithium ion conductivity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid-state electrolyte is used instead of liquid electrolyte, then safety issues such as short circuit and electrolyte leakage are avoided, but lithium ion conductivity deteriorates
Solution Approach 1:
The patent employs a composite solid-state electrolyte consisting of PVDF-HFP polymer matrix combined with LiTFSI salt and ALD-LLZO ceramic particles. This composite structure integrates the mechanical flexibility and ion transport capability of the polymer with the high ionic conductivity and structural stability of the ceramic filler, thereby simultaneously improving safety and lithium ion conductivity compared to conventional single-phase solid electrolytes
Solution Approach 2:
The patent applies atomic layer deposition (ALD) to create a localized thin film coating on the LLZO particles within the electrolyte composite. This local modification enhances the interfacial properties between ceramic filler and polymer matrix, improving lithium ion transport at critical interfaces without compromising the overall safety benefits of the solid-state structure
2Reliability
If dual-layer polymer electrolyte is used, then short circuit and electrolyte leakage problems are solved, but lithium ion conductivity remains poor
Solution Approach 1:
The patent enhances the dual-layer polymer electrolyte by incorporating ALD-LLZO ceramic particles into the composite structure. The ceramic filler provides high ionic conductivity pathways while the polymer matrix maintains the dual-layer architecture for short circuit prevention, achieving both objectives simultaneously
Solution Approach 2:
The patent modifies the electrolyte composition by optimizing the ratio of PVDF-HFP polymer to LiTFSI salt and incorporating ALD-LLZO particles with specific morphology and distribution. These parameter changes enhance lithium ion conductivity while preserving the dual-layer structure's short circuit prevention capability
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 composite membrane achieves improved lithium ion conductivity and mechanical strength, reducing the risk of short circuits and electrolyte leakage, thereby enhancing the safety and performance of all-solid-state lithium ion batteries.
Implementation Method 1
is formed by subjecting a first composition including a first initiator and a first component that includes an acrylic material, lithium bis(trifluoromethanesulfonyl)imide and succinonitrile to a first polymerization reaction
Data Source
AI summary
Disclosed herein is a solid-state composite polymer electrolyte membrane including a solid-state electrolyte layer and a cured electrolyte layer disposed thereon. The solid-state electrolyte layer includes poly(vinylidene fluoride-co-hexafluoropropylene), lithium bis(trifluoromethanesulfonyl)imide, succinonitrile, and aluminum-doped lithium lanthanum zirconium oxide that is present from 50 wt % to 80 wt % based on 100 wt % of the solid-state electrolyte layer. The first cured electrolyte layer is formed by subjecting a first composition including a first initiator and a first component that includes an acrylic material, lithium bis(trifluoromethanesulfonyl)imide and succinonitrile to a first polymerization reaction. The acrylic material is selected from ethoxylated trimethylolpropane triacrylate, poly(ethylene glycol) dimethacrylate, poly(ethylene glycol) methacrylate, and combinations thereof. An all-solid-state lithium ion battery including the solid-state composite polymer electrolyte membrane is also disclosed.