Block Copolymer Electrolytes for Lithium Battery Safety
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Solution Overview
Problem
Current polysiloxane-based electrolytes for lithium secondary batteries have low ionic conductivity and inadequate mechanical properties, limiting their use in high-performance applications and battery lifespan due to flexibility and creep issues.
Innovation Solution
Development of block copolymers combining a siloxane-based polymer block with a structural polymer block, enhanced with salts like lithium salts, to create ionically conductive materials with improved mechanical stability and high ionic conductivity, utilizing thermoplastic polymers and oligo(ethylene oxide) grafted polysiloxanes for battery applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polysiloxane-based electrolytes are used to address safety issues, then flammability and chemical reactivity are reduced, but ionic conductivity decreases
Solution Approach 1:
The patent employs block copolymers that combine polysiloxane blocks (providing safety benefits) with polyethylene oxide blocks (providing high ionic conductivity). This composite structure allows the electrolyte to simultaneously achieve reduced flammability and high ionic conductivity, resolving the contradiction between safety and performance
2Strength
If polysiloxane-based electrolytes are used to improve mechanical properties, then structural support is provided, but ionic conductivity decreases
Solution Approach 1:
The block copolymer structure combines rigid polysiloxane segments (providing mechanical strength) with flexible polyethylene oxide segments (providing ionic conductivity pathways). This composite architecture enables the electrolyte to maintain both mechanical integrity and high ionic conductivity without requiring separate supporting materials
3Reliability
If flexible amorphous polymers are used to achieve high room temperature ionic conductivity, then ionic conductivity increases, but mechanical stability decreases
Solution Approach 1:
The patent creates a block copolymer where rigid polysiloxane blocks provide mechanical stability and structural support, while flexible polyethylene oxide blocks provide the amorphous matrix necessary for high ionic conductivity. This composite structure eliminates the need to choose between flexibility and mechanical stability
Solution Approach 2:
The electrolyte is segmented into distinct functional blocks: polysiloxane blocks for mechanical stability and polyethylene oxide blocks for ionic conductivity. This segmentation allows each block to perform its specialized function without compromising the other, achieving both mechanical stability and high ionic conductivity simultaneously
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 new block copolymer electrolytes exhibit both high ionic conductivity and mechanical stability, suitable for use in batteries and energy storage devices, with ionic conductivity values of 10−4-10−5 S/cm at room temperature, enhancing battery performance and lifespan.
Implementation Method 1
These block copolymers can be combined with salts (such as lithium salts) to create ionically conductive materials
Data Source
AI summary
The present invention relates generally to electrolyte materials. According to an embodiment, the present invention provides for a solid polymer electrolyte material that has high ionic conductivity and is mechanically robust. An exemplary material can be characterized by a copolymer that includes at least one structural block, such as a vinyl polymer, and at least one ionically conductive block with a siloxane backbone. In various embodiments, the electrolyte can be a diblock copolymer or a triblock copolymer. Many uses are contemplated for the solid polymer electrolyte materials. For example, the novel electrolyte material can be used in Li-based batteries to enable higher energy density, better thermal and environmental stability, lower rates of self-discharge, enhanced safety, lower manufacturing costs, and novel form factors.