Polymer Electrolyte Composition for Rechargeable Lithium Battery
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Solution Overview
Problem
Conventional rechargeable lithium batteries experience significant swelling at high temperatures due to electrolyte decomposition, which existing polymer electrolyte solutions have not adequately addressed.
Innovation Solution
A polymer electrolyte composition is developed using a polymerization reaction product of a multifunctional monomer, a polymerization initiator, a non-aqueous organic solvent, and a lithium salt, which inhibits high-temperature swelling by cross-linking the polymer electrolyte, thereby enhancing its thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional organic solvents are used in the electrolyte, then the battery can operate at high temperatures, but severe expansion and swelling occur due to decomposition
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a polymer component with specific molecular structure (polymer chain containing heteroatoms such as O, N, S) and controlling the ratio of polymer to solvent (1:4 to 4:1 by weight). This parameter change transforms the electrolyte from a conventional liquid system to a polymer-based system that maintains operational temperature range while preventing decomposition-induced swelling.
Solution Approach 2:
The patent creates a composite electrolyte system combining polymer chains with specific functional groups (containing heteroatoms) and conventional organic solvents. The polymer component acts as a structural framework that restricts solvent expansion, while the solvent provides ionic conductivity. This composite structure resolves the contradiction between high-temperature operation and swelling prevention.
2Stability of the object's composition
If polymer electrolyte is used to reduce swelling, then thermal stability improves, but battery capacity may be reduced
Solution Approach 1:
The patent introduces local quality variations in the polymer structure by incorporating specific functional groups containing heteroatoms (O, N, S) at specific positions along the polymer chain. These localized functional groups provide sites for lithium ion coordination and transport, ensuring that the polymer structure maintains both thermal stability and adequate ion conductivity for battery capacity.
Solution Approach 2:
The patent optimizes the molecular weight, chain structure, and functional group density of the polymer to balance thermal stability and ion conductivity. By controlling these parameters, the electrolyte achieves sufficient thermal resistance while maintaining adequate lithium ion transport capability to preserve battery capacity.
3Object-affected harmful factors
If cross-linking of polymer electrolyte is increased to improve thermal stability, then high-temperature swelling is reduced, but the electrolyte becomes more rigid and may reduce ion conductivity
Solution Approach 1:
The patent employs localized cross-linking through functional groups containing heteroatoms at specific positions along the polymer chain rather than extensive cross-linking throughout the entire structure. This localized approach provides sufficient structural reinforcement to prevent swelling while leaving sufficient uncross-linked regions to maintain lithium ion conductivity pathways.
Solution Approach 2:
The patent controls the degree of cross-linking by adjusting the concentration and reactivity of functional groups in the polymer structure. This parameter control ensures that the cross-linking density is sufficient to prevent high-temperature swelling but not so high as to create excessive rigidity that would block ion transport.
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 electrolyte composition effectively suppresses high-temperature swelling while maintaining high battery capacity, as demonstrated by a 3% increase in battery thickness compared to 10.3% in comparative examples, indicating improved thermal performance.
Implementation Method 1
the polymerization reaction product of a polymer reactant mixture comprising a multifunctional monomer represented by formula (1); a polymerization initiator
Implementation Method 2
The electrolyte includes lithium salts and organic solvents
Data Source
AI summary
Disclosed is a polymer electrolyte composition for a rechargeable lithium battery including a multifunctional monomer represented by formula 1, a polymer initiator, a non-aqueous organic solvent, and a lithium salt:where A is one represented by one of formulae 1a, 1b, or 1c;where n is an integer of 1 to 10; R1 to R7 are the same or are independently selected from H, C1 to C3 alkyls, and C≡N; and X is a C1 to C20 aliphatic or aromatic carbon, or polyether.