Dendritic Polymer Electrode for Lithium Ion Battery
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Solution Overview
Problem
Conventional lithium ion secondary battery electrodes experience capacity degradation due to decreased binding strength during charging and discharging, leading to reduced energy density, as increasing the binder amount compromises wettability and impregnability of the electrolytic solution.
Innovation Solution
Incorporating a dendritic polymer chemically bonded to the electrode active material and binder, which enhances binding strength without increasing the binder amount, maintaining electrode density and preventing swelling during electrolytic solution impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of binder is increased to strengthen binding strength and suppress expansion and contraction, then binding strength is improved, but wettability and impregnability of electrolytic solution decrease, resulting in lower electrode performance and longer aging time
Solution Approach 1:
A dendritic polymer is introduced as an intermediary substance between the electrode active material particles and the binder. The dendritic polymer chemically bonds to both the electrode active material and the binder, creating a bridging structure that enhances binding strength without requiring increased binder content. This intermediary structure allows the binder to maintain its original amount while achieving superior binding performance and preserving electrolytic solution impregnability.
Solution Approach 2:
The invention creates a composite structure consisting of electrode active material particles bound by dendritic polymers, which are in turn bound by a binder. This multi-component composite system combines the binding capabilities of both dendritic polymers and traditional binders, achieving enhanced binding strength while maintaining the original binder amount and preserving electrolytic solution wettability and impregnability.
2Strength
If the amount of binder is increased to strengthen binding strength, then binding strength is improved, but the electrode swells during impregnation with electrolytic solution, reducing the density of electrode active material and lowering energy density
Solution Approach 1:
The dendritic polymer serves as an intermediary that provides structural support and binding functionality without requiring increased binder content. By chemically bonding to both electrode active material particles and the binder, the dendritic polymer creates a rigidified structure that prevents electrode swelling during electrolytic solution impregnation, thereby maintaining electrode density and energy density while achieving enhanced binding strength.
Solution Approach 2:
The invention changes the structural parameters of the electrode by introducing dendritic polymers with specific molecular architectures (branching structures) that provide rigidity and volume stability. This structural modification prevents the electrode from swelling during impregnation, maintaining the density of electrode active material at high levels (95% or more of pre-impregnation density) and preserving energy density.
3Ease of manufacture
If only binder is used to bind electrode active material, then manufacturing simplicity is maintained, but binding strength decreases with charging and discharging cycles
Solution Approach 1:
The dendritic polymer is introduced as an intermediary that chemically bonds to both electrode active material particles and the binder, creating a dual-bonding structure. This intermediary layer provides additional binding points and distributes mechanical stress during charging and discharging cycles, significantly enhancing binding strength and durability while maintaining manufacturing simplicity through a straightforward mixing and coating process.
Solution Approach 2:
The invention creates a composite binding system where dendritic polymers and traditional binders work synergistically. The dendritic polymers provide initial binding and structural framework, while the traditional binder provides additional adhesion and flexibility. This composite approach maintains manufacturing simplicity while dramatically improving binding strength retention during charging and discharging cycles.
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
This approach maintains the energy density of lithium ion secondary batteries by preventing density loss and minimizing space requirements in the battery cell, while ensuring high volumetric energy density and durability.
Implementation Method 1
The dendritic polymer is chemically bonded to a surface of the electrode active material
Implementation Method 2
The dendritic polymer and the binder are chemically bonded to each other
Data Source
AI summary
To provide an electrode for a lithium ion secondary battery in which the binding strength of an electrode active material can be increased without increasing the amount of a binder, and a desirable energy density of the lithium ion secondary battery can be achieved, and a method of manufacturing the same. An electrode for a lithium ion secondary battery includes an electrode active material, a dendritic polymer, and a binder. The dendritic polymer is chemically bonded to a surface of the electrode active material. The dendritic polymer and the binder are chemically bonded to each other.