Dual Conductive Polymer Binder for Electrochemical Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional binders in electrochemical devices are insulators, lacking ionic and electrical conductivity, which limits the mass and volumetric capacity, energy density, and power density of these devices, and fail to provide mechanical strength for thick electrodes.
Innovation Solution
Development of ion conducting and electron conducting polymers, such as PEDOT: multi-lithium sulfonate polymers, which can be used as dual conductive binders to replace conventional binders and conductive agents, providing both electronic and ionic conductivity, flexibility, and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulating binders are used, then the binder provides mechanical support and holds active material particles together, but the device lacks ionic and electrical conductivity, limiting mass and volumetric capacity, energy density, and power density
Solution Approach 1:
The binder material's electrical and ionic conductivity parameters are fundamentally changed by transitioning from conventional insulating polymers to conductive polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives. This parameter change enables the binder to simultaneously provide mechanical support and conductive pathways, eliminating the need for separate conductive agents and improving overall device performance
Solution Approach 2:
The invention employs composite polymer structures combining conductive polymer backbones (e.g., PEDOT) with functional side chains or dopants that provide both mechanical integrity and ionic/electrical conductivity. These composite materials integrate multiple functions (binding, conducting, and structural support) into a single binder system
2Stability of the object's composition
If conventional binders are used, then the electrode structure is maintained, but the mass and volumetric capacity, energy density, and power density are limited due to the inert nature of the binder
Solution Approach 1:
The conductive polymer binder performs multiple functions simultaneously: it acts as a structural binder holding particles together, provides electrical conductivity pathways for electron transport, offers ionic conductivity for ion transport, and contributes to the overall electrode stability. This multi-functionality eliminates the need for separate conductive agents and maximizes the active material content
3Quantity of substance
If thick electrodes are used to increase capacity, then the mass and volumetric capacity improve, but the electrode stability during swelling and contracting due to ion movement deteriorates
Solution Approach 1:
The mechanical properties of the binder are changed by using conductive polymers with enhanced elasticity and flexibility compared to conventional binders. These modified mechanical parameters enable the binder to accommodate the swelling and contracting of thick electrodes during charge-discharge cycles without losing structural integrity
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 dual conductive binders enhance the performance of electrochemical devices by increasing the mass and volumetric capacity, improving energy density and power density, and maintaining electrode integrity, especially in thick electrodes, while being environmentally benign and easy to handle.
Implementation Method 1
wherein a sulfonic acid group of each branch of the first polymer electronically interacts with one or more thiophene rings of the second polymer
Implementation Method 2
ion exchanging hydrogen with lithium using LiOH or LiCl to convert excess —SO3H to —SO3Li
Data Source
AI summary
An ion conducting and electron conducting polymer is comprised of a first polymer of a single-sulfonic acid polymer or a multi-sulfonic acid polymer and a second polymer of an EDOT analog monomer having the following formula:wherein z=O or S;Y2=—COH, —C6H13, or —COOH; a=0 or 1; Y3=—CH3, —C2H5, —CH2C6H6, —C6H13, —C8H17, —CH2OC6H13, or —CH2OC6H6; and b=0 or 1; wherein a sulfonic acid group of each branch of the first polymer electronically interacts with one or more thiophene rings of the second polymer; and wherein any remaining sulfonic acid groups on each branch of the first polymer are converted to SO3Li.