Ester Polymer Protective Layer for Battery Electrode Interfaces
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Solution Overview
Problem
The interface performance of active substances in electrode plates is poor, leading to poor cycling and storage performance of battery cells due to side reactions between the active substances and electrolytes.
Innovation Solution
A polymer with a specific elastic modulus G′-energy loss modulus G″ curve slope (1<K<∞) and a glass transition temperature (Tg) is applied to form a protective layer on the surface of active substances, reducing side reactions and improving the solid-liquid interface performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the polymer maintains molecular chain entanglement to prevent dissolution in electrolyte, then polymer stability is improved, but solvent diffusion between molecular chains is hindered
Solution Approach 1:
The patent adjusts the glass transition temperature parameter of the polymer to the range of -100≤Tg≤50°C, which optimizes the balance between molecular chain entanglement and chain segment flexibility. This parameter change allows the polymer to maintain stability while enabling adequate solvent diffusion for ion transmission.
Solution Approach 2:
The patent uses an ester polymer with specific structural units (formulas I, II, and their variants) that create a composite molecular structure. This composite structure provides both the entanglement needed for stability and the flexibility required for solvent diffusion, resolving the contradiction between these two properties.
2Reliability
If the polymer forms a protective layer on active substance surface, then interface performance is improved, but ion transmission may be hindered
Solution Approach 1:
The patent employs a thin polymer film that forms a protective layer on the active substance surface. This flexible film structure provides interface protection while maintaining ion transmission capability, as the thin film does not completely block ion pathways.
Solution Approach 2:
The polymer structure creates a porous or network-like protective layer that allows ion transmission. The molecular chain arrangement forms channels or pores through which ions can pass while the polymer matrix provides protective functions.
3Ease of operation
If the glass transition temperature is lowered to increase chain segment flexibility, then molecular chain mobility is improved, but polymer structural stability may decrease
Solution Approach 1:
The patent optimizes the glass transition temperature parameter to a specific range (-100≤Tg≤50°C) that balances chain mobility and structural stability. This parameter optimization ensures the polymer remains flexible enough for ion transmission while maintaining sufficient structural integrity.
Solution Approach 2:
The ester polymer with specific structural units creates a composite molecular architecture that provides both flexibility and stability. The molecular structure combines elements that promote chain mobility with elements that maintain structural coherence.
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 polymer enhances the cycling and storage performance of battery cells by forming a protective layer that stabilizes the interface, reducing side reactions and maintaining normal ion transmission.
Implementation Method 1
the polymer to form a protective layer on the surface of an active substance
Implementation Method 2
the solvent molecules can be locked in situ in the polymer
Implementation Method 3
facilitating the diffusion of solvent molecules in an electrolyte between molecular chains
Data Source
AI summary
A polymer includes an ester polymer, and the polymer is applied to battery cells. The ester polymer is made into a sheet structure. The sheet structure undergoes dynamic frequency scanning testing at (Tm+20)° C. to obtain an elastic modulus G′-energy loss modulus G″ curve, where a slope of the elastic modulus G′-energy loss modulus G″ curve is K, 1<K<∞, and Tm° C. represents a melting temperature of the ester polymer.