Copolyester Electrode Binders for Recyclable Li-Ion Cells
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Solution Overview
Problem
Current lithium-ion battery electrodes, particularly those using polyvinylidene fluoride (PVDF) binders, face challenges in recyclability and safety due to the formation of toxic gases at high temperatures and the difficulty in dissolving PVDF for environmentally friendly recovery, as well as issues with interfacial compatibility between solid electrodes and separators in dry-cell batteries, leading to potential short-circuiting and flammability.
Innovation Solution
Development of electrodes using a binder material comprising a copolyester derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), which may include conductive ceramic particulate materials and metal ions, enhancing recyclability and interfacial compatibility with solid separators while maintaining electronic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVDF binder is used in electrodes, then electrochemical stability and rheological properties are improved, but recyclability deteriorates due to toxic gas formation and difficulty in solvent-based recovery
Solution Approach 1:
The patent changes the chemical composition parameter of the binder from PVDF to copolyester containing poly(alkylene oxide) units. This parameter change enables the binder to be dissolved in water or alcohol-based solvents instead of requiring toxic solvents, thereby improving recyclability while maintaining electrochemical stability through the stable ester backbone structure
Solution Approach 2:
The patent creates a composite binder material combining copolyester with conductive ceramic particulate materials and metal ions. This composite structure provides both the electrochemical stability needed for battery operation and the solubility characteristics enabling environmentally friendly recycling through water or alcohol-based solvents
2Ease of manufacture
If copolyester binder with poly(alkylene oxide) is used, then recyclability is improved through water or alcohol-based solvent dissolution, but electronic conductivity may deteriorate
Solution Approach 1:
The patent creates a composite binder system combining copolyester with conductive ceramic particulate materials and metal ions. The copolyester matrix provides water or alcohol solubility for easy recycling, while the conductive ceramics and metal ions embedded within restore and enhance electronic conductivity, achieving both recyclability and electrical performance
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 binder material improves the recyclability and interfacial compatibility of lithium-ion battery electrodes, reducing the risk of short-circuiting and flammability, and extends the battery's cycling ability and lifetime by maintaining effective contact between the electrodes and separators.
Implementation Method 1
The binder material must enable migration of the lithium ions through the electrode
Implementation Method 2
the binder material may further comprise a first metal ion-containing component selected from conductive ceramic particulate materials
Data Source
AI summary
An electrode constituted by an active material and a binder material, wherein the binder material comprises a copolyester which comprises repeating units derived from a diol, a dicarboxylic acid and a poly(alkylene oxide). The binder material may further comprise a first metal ion-containing component selected from conductive ceramic particulate materials, and/or may further comprise additional metal ions from one or more sources other than said conductive ceramic particulate materials.