Ion-Conductive Polymer Binder for Lithium-Ion Electrode Adhesion
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Solution Overview
Problem
Existing binders for lithium secondary batteries, such as styrene-butadiene rubber (SBR), hinder lithium ion mobility and reduce adhesive strength, leading to increased resistance and reduced cycle life.
Innovation Solution
Development of an ion-conductive polymer with lithium-ion conductivity and high adhesion performance, incorporating a cyano group to enhance lithium ion mobility and chemical bonding with styrene-butadiene rubber, maintaining stability and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If styrene-butadiene rubber (SBR) is used as a binder, then adhesive strength is maintained, but lithium ion mobility is hindered and resistance increases
Solution Approach 1:
The invention modifies the chemical structure of the binder by introducing a cyano group (—C≡N) into the polymer chain. This parameter change in molecular structure transforms the binder from an insulating material (SBR) to an ion-conductive material, enabling lithium ion mobility while preserving adhesive properties. The cyano group's high electron negativity creates ion-conductive pathways without compromising the binder's bonding capability.
Solution Approach 2:
The invention creates a composite binder structure combining the mechanical strength and adhesion of SBR with the ion-conductive properties of cyano-containing functional groups. This composite approach integrates two previously separate functions (adhesion and ion conduction) into a single material system, resolving the contradiction between maintaining structural integrity and enabling ion transport.
2Object-generated harmful factors
If (meth)acrylic acid ester-based polymer is used, then lithium ion mobility is improved, but adhesive strength decreases and cycle life is reduced
Solution Approach 1:
The invention adjusts the chemical parameters of the polymer by incorporating specific cyano-containing functional groups with controlled electron negativity and steric effects. This parameter optimization allows the binder to achieve both high ion conductivity and strong adhesion, overcoming the limitation of conventional acrylate polymers that sacrifice adhesive strength for ion mobility.
Solution Approach 2:
The invention introduces ion-conductive cyano groups at specific locations within the polymer structure, creating localized ion-conductive pathways while maintaining the overall structural integrity and adhesive properties of the binder matrix. This local modification approach enables selective enhancement of ion conductivity without compromising global adhesive performance.
3Quantity of substance
If coating amount of anode is increased to maximize energy density, then energy density is improved, but coating conditions become stricter and resistance increases
Solution Approach 1:
The invention changes the electrical and chemical parameters of the binder to reduce electrode resistance, which relaxes the strictness of coating conditions. By making the binder ion-conductive, the system can accommodate higher coating amounts without proportionally increasing resistance, thereby enabling higher energy density while maintaining manufacturability.
4Ease of manufacture
If conventional binders are used, then manufacturing simplicity is maintained, but cycle life is reduced due to decreased adhesive strength
Solution Approach 1:
The invention modifies the chemical composition parameters of the binder by incorporating cyano-containing functional groups, which enhance both adhesive strength and electrochemical stability. This parameter change improves cycle life while maintaining compatibility with conventional manufacturing processes, as the modified binder retains the ease of processing characteristics of traditional polymer binders.
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 ion-conductive polymer improves lithium ion mobility, maintains adhesion, and enhances battery performance by stabilizing performance during cycling, offering high mechanical strength and electrolyte stability.
Implementation Method 1
a functional group having lithium-ion conductivity
Implementation Method 2
chemical bonding with styrene-butadiene rubber
Data Source
AI summary
The present disclosure relates to an ion-conductive polymer, an electrode including the same, and a lithium secondary battery including the electrode. The ion-conductive polymer includes a first monomer represented by Formula 1 below.In Formula 1, A, L1 to L2, L11, a1 to a2, a11, R1 to R3, and n1 to n2 are as defined in the detailed description.