Anode Binder Solution Relieving Volume Expansion
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Solution Overview
Problem
Lithium intercalation and disintercalation in anode active materials lead to volume expansion, causing cracks in the anode active material layer, which deteriorates the charging and discharging characteristics and life characteristics of electrochemical devices.
Innovation Solution
A binder solution for the anode comprising a thermally cross-linkable polymer binder with a carboxyl group, such as polyacrylic acid, and a water-based binder, applied in a specific weight ratio, is used to form a cross-linked polymer network that relieves volume expansion and improves coating stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binders are used in anode active material, then the anode can be manufactured, but volume expansion during lithium intercalation causes cracks and deteriorates device life
Solution Approach 1:
The patent changes the chemical parameters of the binder by using a carboxyl-containing polymer with specific functional groups (carboxyl groups) that can form cross-linked networks. This chemical parameter change enables the binder to withstand volume expansion during lithium intercalation, preventing cracks and improving both device life characteristics and anode layer durability simultaneously.
Solution Approach 2:
The patent creates a composite binder system by combining a carboxyl-containing polymer with specific solvents (alcohols, carboxylic acids, or their mixtures) in controlled ratios. This composite formulation forms a cross-linked network structure that provides both mechanical strength to prevent cracking and flexibility to accommodate volume changes, resolving the contradiction between durability and device life.
2Strength
If the binder solution provides strong adhesion to prevent cracks, then anode layer durability improves, but coating stability and dispersibility may deteriorate
Solution Approach 1:
The patent uses specific solvents (alcohols, carboxylic acids, or their mixtures) as intermediaries between the carboxyl-containing polymer binder and the anode active material. These intermediary solvents provide both good dispersibility during coating application and facilitate cross-linking for strong adhesion, thereby maintaining coating stability while achieving durable anode layers that resist cracking.
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 solution effectively enhances the durability of the anode active material layer, maintaining good dispersibility and stability, thereby improving the life characteristics and capacity retention of electrochemical devices.
Implementation Method 1
a thermally cross-linkable polymer binder which is cross-linked by heat
Implementation Method 2
the thermally cross-linkable polymer binder may comprise a carboxyl group as a functional group
Data Source
AI summary
The present disclosure relates to a binder solution for an anode, comprising a thermally cross-linkable polymer binder that is cross-linked by heat, and a solvent for dissolving the thermally cross-linkable polymer binder, and exhibiting a concentration of hydrogen ions corresponding to pH 2.5 to pH 4.5; an active material slurry for an anode, comprising the binder solution; an anode using the slurry; and an electrochemical device comprising the anode. The binder solution for an anode according to one aspect of the present disclosure can relieve the volume expansion of an anode active material by the intercalation and disintercalation of lithium during cycles of electrochemical devices to improve the durability of an anode active material layer, thereby enhancing the life characteristics of the electrochemical devices, and also can provide good dispersibility to the active material slurry for an anode, thereby improving the coating stability of an anode active material layer.