Composite Electrode Using Elastic Conductive Polymer Binder
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Solution Overview
Problem
Conventional lithium-ion battery electrodes suffer from instability due to volume expansion during charging and discharging, leading to reduced service life and inadequate energy density.
Innovation Solution
A composite electrode comprising an elastic, conductive polymeric binder and a conversion material, such as transition metal compounds like FeF3 or CuS, which allows for high energy density and rapid charging/discharging rates without the need for excessive conductivity additives, thereby minimizing volume changes and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binders (polyvinylidene fluoride, acrylic acid, or cellulose) with conductivity additives are used, then electrical conductivity is provided, but the electrode material becomes unstable due to volume expansion during charging and discharging
Solution Approach 1:
The patent changes the chemical composition and physical properties of the binder by using conductive polymers (polyaniline, polypyrrole, polythiophene, PEDOT, or their derivatives) instead of conventional binders. These polymers inherently provide both binding functionality and electrical conductivity without requiring additional conductivity additives, thereby eliminating the volume expansion problem associated with conventional binder systems.
Solution Approach 2:
The patent creates a composite electrode structure consisting of active material particles combined with conductive polymer binder. This composite material integrates the binding function and conductivity function into a single unified system, where the conductive polymer matrix provides mechanical cohesion while maintaining electrical pathways, solving the instability issue of conventional composite electrodes.
2Reliability
If conductivity additives (carbon black, carbon nanotubes) are added to conventional binders, then electrical conductivity is achieved, but the electrode composition becomes insufficiently stable under charging and discharging conditions
Solution Approach 1:
The patent merges the binding function and conductivity function into a single conductive polymer binder material. This eliminates the need for separate conductivity additives and simplifies the electrode composition to just three components: active material, conductive polymer binder, and solvent. The conductive polymer inherently provides both mechanical cohesion and electrical pathways.
Solution Approach 2:
The patent extracts and eliminates the conductivity additives (carbon black, carbon nanotubes) from the conventional binder system. By using conductive polymers that inherently provide conductivity, the patent removes the need for these additional components, simplifying the overall electrode composition while maintaining stability.
3Productivity
If conversion materials are used to achieve high energy density, then charging and discharging rates improve, but volume changes occur that reduce cell lifespan
Solution Approach 1:
The patent changes the mechanical properties of the electrode matrix by using elastic conductive polymers that can dynamically adjust to volume changes of conversion materials during lithiation and delithiation. This elasticity parameter change allows the binder to accommodate volume expansion and contraction without causing electrode degradation, thereby extending cell lifespan while maintaining high charging and discharging rates.
4Strength
If conventional binder systems are used, then mechanical cohesion is provided, but excessive conductivity additives are required which hinder volume changes and reduce stability
Solution Approach 1:
The patent merges the binding function and conductivity function into a single conductive polymer binder material. This eliminates the need for separate conductivity additives and simplifies the electrode composition to just three components: active material, conductive polymer binder, and solvent. The conductive polymer inherently provides both mechanical cohesion and electrical pathways.
Solution Approach 2:
The patent changes the mechanical properties of the electrode matrix by using elastic conductive polymers that can dynamically adjust to volume changes of conversion materials during lithiation and delithiation. This elasticity parameter change allows the binder to accommodate volume expansion and contraction without causing electrode degradation, thereby extending cell lifespan while maintaining high charging and discharging rates.
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 composite electrode achieves high energy density and long-term stability, enabling high-capacity applications like automotive use with improved charging and discharging rates.
Implementation Method 1
Due to its chemical structure, such a binder is both electrically conductive and lithium-ion conductive
Implementation Method 2
components for lithium transport, lithium-ion transport, and lithium-ion storage
Implementation Method 3
The transition metal is completely reducible in a single cell charging process of the electrochemical cell
Implementation Method 4
conversion material is a chemical compound comprising at least one transition metal M and one anion X
Implementation Method 5
the conductivity additives present in conventional composite electrodes hinder the volume changes of the composite electrode during lithium ion storage and release
Data Source
Figure 1~2
AI summary
The invention relates to a composite electrode (1) for an electrochemical cell, comprising a conversion material (3) and an elastic, conductive polymer binder (4). The conversion material (3) comprises at least one transition metal (M) and an anion (X). The transition metal can be completely reduced in a cell charging process of the electrochemical cell.