Single-Ion Polymer Electrolyte for Lithium-Ion Batteries
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Solution Overview
Problem
Current lithium-ion batteries face limitations due to binary salt conductors, where anion mobility leads to concentration polarization and reduced power density, while single-ion conductors with low-glass transition temperature polymers offer limited improvement in ionic conductivity and compromise mechanical and thermal stability.
Innovation Solution
Development of a new class of single-ion electrolytes based on pendant lithium perfluoroethyl sulfonates within aromatic poly(arylene ether)s, polyphenylenes, or polyarylene sulfides, forming microporous polymer films that achieve unity lithium ion transference number and high ionic conductivity, along with excellent mechanical and electrochemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If binary salt conductors are used in lithium-ion batteries, then ionic conductivity is maintained, but anion mobility causes concentration polarization and reduces power density
Solution Approach 1:
The patent extracts and eliminates the mobile anion component from the electrolyte system by using single-ion conductors where anions are covalently bound to the polymer backbone, removing the source of concentration polarization while maintaining ionic conductivity through lithium ion transport
2Reliability
If single-ion conductors with low-glass transition temperature polymers are used, then lithium ion transference number improves, but mechanical integrity and thermal stability are compromised
Solution Approach 1:
The patent changes the glass transition temperature parameter of the polymer from low (in conventional single-ion conductors) to high (above 100°C), achieving both unity lithium ion transference number and excellent mechanical integrity through the novel aromatic poly(arylene ether) backbone structure
Solution Approach 2:
The patent creates a composite material system combining aromatic poly(arylene ether) polymer matrix with covalently attached lithium salts, achieving synergistic properties where the rigid aromatic backbone provides mechanical strength while the lithium-containing side chains enable ionic conduction
3Reliability
If single-ion conductors with low-glass transition temperature polymers are used, then lithium ion transference number improves, but thermal stability is compromised
Solution Approach 1:
The patent changes the thermal stability parameter by designing a polymer with decomposition temperature above 350°C through the use of aromatic rings and ether linkages in the backbone, while maintaining unity lithium ion transference number through covalent attachment of lithium salts
4Object-generated harmful factors
If conventional single-ion conductors are used, then anion mobility is eliminated, but overall electrolyte conductivity is significantly depressed
Solution Approach 1:
The patent applies local quality by creating mobile lithium ion sites through covalently attached lithium salts on the polymer backbone while keeping the polymer backbone itself stationary, enabling high lithium ion conductivity without anion mobility through localized cationic transport pathways
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 single-ion electrolytes demonstrate state-of-the-art conductivities, high electrochemical stability, and outstanding mechanical properties, enabling them to function as both ion conductors and separators in lithium-ion batteries with excellent cyclability and practical application potential.
Implementation Method 1
Single-ion conducting electrolytes in which the anionic species is anchored to a polymer and becomes immobile present a unique alternative to traditional binary salt conductors
Implementation Method 2
The microporous polymer film saturated with organic carbonates exhibits a nearly unity tLi+
Data Source
AI summary
We report a new class of single-ion electrolyte including pendant lithium perfluoroethyl sulfonates. Embodiments may be based on, for example, aromatic poly(arylene ether)s, polyphenylenes, or polyarylene sulfides. The microporous polymer film saturated with organic carbonates exhibits a nearly unity tLi+, state-of-the-art conductivities (e.g. >10−3 S cm−1 at room temperature) over a wide range of temperatures, high electrochemical stability, and outstanding mechanical properties, which enables the membrane to function as both ion conducting medium and separator in the batteries.