Temperature-Sensitive Electrode Binder to Prevent Anode Layer Lifting
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Solution Overview
Problem
In lithium secondary batteries, the binder used in the electrode active material layer migrates to the surface during drying, reducing its adhesive force with the base material and leading to electrode degradation, necessitating additional coating processes that increase production complexity.
Innovation Solution
A binder comprising styrene-butadiene rubber particles with a temperature-sensitive polymer, such as poly-N-isopropylacrylamide, grafted onto the surface, which shrinks at a lower critical solution temperature, enhancing bonding forces between the active material layer and the base material, preventing layer lifting during drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional binder is used in the active material layer, then the electrode can be manufactured with a simple process, but the binder migrates to the surface during drying, reducing adhesive force with the base material and causing electrode degradation
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by incorporating specific functional groups (carboxyl, hydroxyl, or amine groups) with controlled content ratios. This compositional parameter change prevents binder migration during drying while maintaining strong adhesive force with the base material, resolving the contradiction between manufacturing simplicity and adhesive stability.
Solution Approach 2:
The invention creates a composite binder system combining styrene-butadiene rubber particles with temperature-sensitive polymer grafts containing specific functional groups. This composite structure provides both the ease of manufacture from conventional materials and the reliability of controlled migration and adhesion through the functional group interactions with the base material.
2Reliability
If additional coating processes are used to prevent binder migration, then adhesive force stability is improved, but the number of manufacturing processes increases
Solution Approach 1:
The binder composition is designed to be self-regulating during the drying process. The temperature-sensitive polymer grafts with specific functional groups automatically control binder migration and adhesion without requiring external intervention or additional coating processes, thus maintaining adhesive stability while keeping the manufacturing process simple.
Solution Approach 2:
The functional groups are pre-incorporated into the binder composition before the coating process. This preliminary preparation ensures that during drying, the binder automatically exhibits controlled migration and strong adhesion without needing subsequent corrective coating steps, reducing process complexity while maintaining reliability.
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 use of temperature-sensitive polymers improves the adhesive strength between the active material layer and the base material, stabilizing the electrode and reducing the risk of layer lifting, thus enhancing the battery's performance and longevity.
Implementation Method 1
the temperature-sensitive polymer may be characterized in that a shape of a polymer chain of the temperature-sensitive polymer shrinks at a lower critical solution temperature
Implementation Method 2
a shape of a polymer chain of the temperature-sensitive polymer shrinks at a lower critical solution temperature
Implementation Method 3
the binder may bond respective materials and form an adhesive force with the base material
Data Source
AI summary
Provided are a binder for an electrode, a negative electrode for a secondary battery including the binder, and a secondary battery, in which an active material layer is prevented from lifting from a negative electrode base material. A binder forming an electrode of a secondary battery includes a binder particle and a temperature-sensitive polymer grafted on a surface of the binder particle.