Organic Cyanide Separator Coating for High-Temperature Battery Stability
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Solution Overview
Problem
High-energy density secondary batteries suffer from high-temperature performance deterioration, leading to safety issues and reduced stability.
Innovation Solution
A separator with a base film coated with an organic cyanide containing a functional group, such as cyano, isocyano, or melamine derivative, is used to stabilize positive electrode structures, reducing active oxygen release and preventing structural phase transitions during high-voltage charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-energy density secondary batteries are used to meet increasing energy demands, then energy density is improved, but high-temperature performance deteriorates and safety issues arise
Solution Approach 1:
An organic cyanide coating layer is introduced as an intermediary between the positive electrode material and the electrolyte. This coating layer mediates the interaction by stabilizing the surface structure of the positive electrode material, preventing direct harmful reactions with the electrolyte at high temperatures, thus improving high-temperature performance while maintaining high energy density
Solution Approach 2:
The surface properties of the positive electrode material are modified by coating with organic cyanide, changing parameters such as surface composition, structure, and energy. This parameter change stabilizes the surface lattice, reduces oxygen release, and prevents structural phase transitions at high temperatures, resolving the contradiction between energy density and high-temperature performance
2Use of energy by moving object
If charging voltage is increased to improve energy density, then energy density is improved, but structural phase transition occurs and safety performance declines
Solution Approach 1:
The organic cyanide coating is applied in advance to the positive electrode material surface before high-voltage charging. This preliminary action pre-stabilizes the surface lattice structure and prevents oxygen release, so that when high-voltage charging occurs, the surface structure remains stable and structural phase transition is avoided
Solution Approach 2:
The organic cyanide coating acts as a protective intermediary layer that buffers the stress and chemical effects during high-voltage charging. It mediates between the high-voltage electrical stress and the positive electrode material, preventing direct damage that would cause structural phase transition
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 enhances thermal safety and high-temperature cycle performance of secondary batteries by stabilizing positive electrode structures and reducing irreversible structural changes.
Implementation Method 1
The organic cyanide diffuses and comes into contact with the surface of a positive electrode material, which can stabilize metal atoms and positive electrode crystal structures
Data Source
AI summary
A separator includes a base film and a first coating disposed on a surface of the base film to face one side of a positive electrode. The first coating includes an organic cyanide with a first functional group. The first functional group includes at least one of a cyano group, an isocyano group, an isocyanate group, or a melamine compound. The first functional group of the first coating has a molar concentration of M fmol/µm3, where 0.1 ≤ M ≤ 30. The secondary battery provided by this application has a high energy density and also has good thermal safety, high-temperature cycle performance and high-temperature storage performance.