Block Polymer Electrolyte Additive for EDLC Cycle Life Stability
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Solution Overview
Problem
Electrical double layer capacitors face challenges in maintaining electrochemical stability and cycle life due to by-product accumulation during high-voltage degradation, leading to limited cycle life and efficiency.
Innovation Solution
A bimolecular block polymer is formed by polymerizing specific compounds with a molar ratio between 5:1 and 1:5, which is used as an additive in the electrolyte to absorb by-products, maintaining electrochemical stability and preventing excessive viscosity, thereby enhancing the capacitor's cycle life and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-voltage operation is maintained to increase energy density, then power output is improved, but by-product accumulation occurs leading to reduced cycle life
Solution Approach 1:
A bimolecular block polymer consisting of a first polymer chain and a second polymer chain is introduced as an intermediary substance in the electrolyte. This polymer acts as a mediator that captures and neutralizes by-products generated during high-voltage charging and discharging cycles, preventing their accumulation and harmful effects on electrode structures, thereby enabling sustained high-power operation without compromising cycle life.
Solution Approach 2:
The invention converts the harmful by-products generated during high-voltage operation into a beneficial process by using the bimolecular block polymer to capture and neutralize these by-products. The polymer transforms the degradation mechanism from a harmful accumulation process into a controlled interaction where by-products are systematically managed, allowing the capacitor to maintain reliability under high-power conditions.
2Stability of the object's composition
If electrolyte additives are added to improve stability, then electrochemical stability is improved, but electrolyte viscosity increases reducing conductivity
Solution Approach 1:
The invention optimizes the molecular weight and compositional ratio of the bimolecular block polymer to achieve the desired balance between stability and conductivity. By carefully controlling the parameters of the polymer structure and its concentration in the electrolyte, the system achieves sufficient by-product capture capability while maintaining low enough viscosity to preserve ionic conductivity and energy efficiency.
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 bimolecular block polymer effectively absorbs by-products, achieving a wide electrochemical stability window and extending the cycle life of electrical double layer capacitors to over 12,000 cycles while maintaining optimal conductivity and charge efficiency.
Implementation Method 1
the bimolecular block polymer acts as an additive may absorb the by-products generated by the electrolyte during high-voltage degradation
Data Source
AI summary
Provided are a bimolecular block polymer and an electrolyte and an electrical double layer capacitor containing the same. The bimolecular block polymer is suitable for an electrolyte of a capacitor, and is formed by polymerizing a first compound and a second compound. The first compound is represented by one of formula (A-1) to formula (A-4). The second compound is represented by one of formula (B-1) to formula (B-5). A molar ratio of the first compound to the second compound is between 5:1 and 1:5.