Nanoceramic-Aramid Separator Slurry for Stronger Thermal-Stable Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium battery separators face issues with poor adhesion between aramid and ceramic particles, leading to potential safety hazards and performance degradation due to thermal shrinkage, low breakage temperature, and uneven pore size distribution, which are not effectively addressed by current compounding methods or ceramic coatings.
Innovation Solution
A composite slurry is prepared by in-situ compounding nanoceramic particles with isocyanate and aramid through a modification and grafting reaction, eliminating the need for binders, thereby enhancing adhesion and improving thermal and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a binder including polar functional groups is used to improve adhesion of ceramic particles, then adhesion is improved, but thermal safety deteriorates due to thermochemical reactions under heat
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the ceramic particles and the polyolefin separator. The silane coupling agent contains both inorganic bonding groups (for bonding to ceramic particles) and organic bonding groups (for bonding to the polyolefin separator), enabling strong adhesion without requiring polar functional groups that cause thermal safety issues. This intermediary resolves the contradiction by providing a bonding mechanism that is both adhesive and thermally stable.
Solution Approach 2:
The patent changes the chemical composition parameters of the binder system by replacing traditional polar binder molecules with silane coupling agents. This parameter change involves selecting silane compounds with specific functional groups that provide both adhesion and thermal stability, thereby improving adhesion strength while maintaining thermal safety under battery operating conditions.
2Temperature
If ceramic coating is applied to improve thermal performance, then thermal shrinkage resistance is improved, but adhesion between ceramic particles and separator deteriorates
Solution Approach 1:
The silane coupling agent serves as a mediator that bridges the inorganic ceramic particles and the organic polyolefin separator. The coupling agent's dual functionality (inorganic and organic bonding groups) enables it to strongly bond to both materials, resolving the adhesion problem while preserving the thermal shrinkage resistance provided by the ceramic coating.
3Shape
If compounding method is used to prepare aramid-coated separator, then coating is achieved, but thickness uniformity and pore size distribution deteriorate
Solution Approach 1:
The patent changes the processing parameters by using a slurry coating method with optimized viscosity and composition, followed by controlled drying and heat treatment. This parameter optimization enables uniform coating thickness and consistent pore size distribution while achieving complete coating coverage, resolving the contradiction between coating formation and manufacturing precision.
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 slurry results in improved peeling strength, breakage temperature, electrolyte contact angle, and gas permeability, along with increased capacity retention and temperature stability of lithium batteries.
Implementation Method 1
hydroxyl on a surface of the nanoceramic particle reacts with an isocyanate group in the isocyanate to obtain a modified nanoceramic particle
Implementation Method 2
an isocyanate group in the modified nanoceramic particle is grafted with an amido bond in the aramid to obtain the composite slurry
Data Source
Figure 1
AI summary
The present disclosure relates to the technical field of lithium battery materials, and provides a composite slurry, and a preparation method and use thereof. The composite slurry allows the compounding of a nanoceramic particle with aramid, which effectively avoids the problem that nanoceramic particles are easy to fall off from a separator due to the use of a binder to bond the nanoceramic particles with the separator in the prior art. Compared with the lithium battery separators in the prior art, a lithium battery separator prepared with the isocyanate-modified nanoceramic particle/aramid in-situ composite slurry exhibits improved properties, such as a peeling strength, a breakage temperature, and an electrolyte contact angle. Compared with the batteries in the prior art, a battery prepared with the lithium battery separator exhibits improved properties, such as a capacity retention rate, a room-temperature capacity, a high-temperature capacity (55°C), and a low-temperature capacity (-20°C).