Vinylene Carbonate Copolymer Electrolyte for Safer Solid-State Batteries
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Solution Overview
Problem
Conventional lithium-ion batteries face safety concerns due to the reactivity of graphite anodes and the use of liquid electrolytes, which can lead to thermal runaway, explosion, or fire, especially in portable and electric vehicle applications, and existing solid polymer electrolytes have limited mechanical integrity and ion conductivity.
Innovation Solution
A copolymer composed of vinylene carbonate and compatible monomers is developed, which can be used as a solid electrolyte or binder in batteries, providing improved ion conductivity and mechanical stability without the need for liquid solvents, and can be formed into conductive films or separators for use in various metal-ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolyte solutions are used in lithium-ion batteries, then ion conductivity is improved, but safety deteriorates due to thermal runaway, explosion, or fire risks
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by using a copolymer composition. The solid electrolyte maintains ion conductivity through its polymer matrix structure while eliminating the flammability and thermal runaway risks associated with liquid electrolytes. The copolymer's amorphous regions provide ion transport pathways similar to liquid electrolytes but with inherent safety advantages.
Solution Approach 2:
The patent employs a composite copolymer system combining vinylene carbonate units with other monomer units to create a solid electrolyte material. This composite structure integrates the beneficial properties of different polymer components to achieve both high ion conductivity and enhanced safety, replacing the liquid electrolyte solution entirely.
2Reliability
If graphite anodes are used to ensure stability, then safety is improved, but energy density deteriorates due to lower lithium storage capacity
Solution Approach 1:
The patent changes the anode material from graphite to a solid electrolyte composition that can serve dual functions. The copolymer-based solid electrolyte enables lithium metal anodes to be used safely by providing a stable interface that prevents dendrite formation and uncontrolled lithium plating, thereby achieving both high stability and high energy density.
3Object-affected harmful factors
If solid polymer electrolytes are used to improve safety, then thermal stability is improved, but ion conductivity and mechanical integrity deteriorate
Solution Approach 1:
The patent creates a composite copolymer electrolyte combining vinylene carbonate units with other monomer units to achieve a balance of properties. The vinylene carbonate units provide thermal stability and structural integrity, while the copolymer structure maintains amorphous regions for ion conduction, overcoming the limitations of simple solid polymers.
Solution Approach 2:
The patent introduces local structural variations within the polymer chains through copolymerization. Different monomer units create local regions with distinct properties: some regions provide structural rigidity and thermal stability, while other amorphous regions facilitate ion transport, achieving both thermal stability and ion conductivity simultaneously.
4Quantity of substance
If lithium metal anodes are used to increase energy density, then capacity is improved, but safety deteriorates due to dendrite formation and thermal runaway risks
Solution Approach 1:
The patent introduces a solid electrolyte interface layer made of copolymer composition as an intermediary between the lithium metal anode and the electrolyte. This intermediate layer prevents direct contact and uncontrolled reactions, suppressing dendrite formation and thermal runaway while maintaining the high capacity benefits of lithium metal anodes.
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 copolymer enhances the safety and performance of lithium-ion batteries by providing a thermally stable, ionically conductive, and flexible solid electrolyte that reduces the risk of thermal runaway and improves energy density, while maintaining mechanical integrity and stability.
Implementation Method 1
a copolymer of a vinylene carbonate compound, fibers, and films made therefrom... providing improved ion conductivity
Implementation Method 2
providing a thermally stable, ionically conductive, and flexible solid electrolyte that reduces the risk of thermal runaway
Data Source
AI summary
A polymer formed from a first monomer of vinylene carbonate and at least one second monomer different form the first monomer that does not contain a glycidyl group, wherein the molar ratio of the first monomer to the second monomer is from 4:1 to 99:1. The polymer, preferably the copolymer, dissolves metal salts and the composition of the copolymer and metal salt may have an ionic conductivity greater than 0.01 mS/cm. The polymer is suitable for use in various components of solid state batteries.