Phosphazene Electrolyte Additive for Lithium Battery Flame Retardancy
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in maintaining stability and performance while enhancing flame retardancy, as existing electrolytes do not effectively balance these requirements.
Innovation Solution
An electrolyte solution comprising a lithium salt, a non-aqueous organic solvent, and a specific electrolyte additive represented by Chemical Formula 1, which includes a disubstituted amino group and halogen atoms, is used to improve flame retardancy without compromising battery performance. The additive is a cyclotriphosphazene derivative, such as monosubstituted pentafluorocyclotriphosphazene, included in a range of 10 to 15 volume % in the electrolyte solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used to maintain battery performance, then stability and performance are maintained, but flame retardancy is insufficient
Solution Approach 1:
The patent uses a composite electrolyte system combining multiple components: a cyclic carbonate (EC), chain carbonates (DMC, DEC), and a phosphazene derivative additive (Formula 1). This composite approach creates synergistic effects where the phosphazene derivative enhances flame retardancy while the carbonate mixture maintains ion conductivity and battery performance, resolving the contradiction between stability and flame safety.
Solution Approach 2:
The patent optimizes the concentration parameter of the phosphazene derivative additive at 1-10 wt% in the electrolyte solution. By precisely controlling this parameter, the invention achieves optimal flame retardancy enhancement while maintaining acceptable battery performance and stability, demonstrating how parameter optimization resolves the contradiction between safety improvement and performance maintenance.
2Object-affected harmful factors
If flame retardant additives are added to improve safety, then flame retardancy is enhanced, but battery performance may deteriorate
Solution Approach 1:
The patent systematically optimizes the concentration parameter of the phosphazene derivative, determining that 1-10 wt% is the optimal range. Below this range, flame retardancy is insufficient; above this range, battery performance deteriorates. This precise parameter control resolves the contradiction by identifying the optimal balance point where safety enhancement does not compromise performance.
Solution Approach 2:
The phosphazene derivative selectively enhances flame retardancy properties without significantly affecting other critical electrolyte functions such as ion solvation and conductivity. The additive acts locally on the flame suppression mechanism while allowing the bulk electrolyte to maintain its performance characteristics, thus resolving the contradiction between safety improvement and performance preservation.
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 flame retardancy of the electrolyte while maintaining the performance and stability of rechargeable lithium batteries, as demonstrated by improved self-extinguishing times and capacity retention during cycling tests.
Implementation Method 1
the electrolyte solution, which can improve flame retardancy and ameliorate performances of a battery
Implementation Method 2
Batteries transform chemical energy generated from an electrochemical redox reaction of a chemical material in the battery into electrical energy
Data Source
Figure 1
AI summary
An electrolyte additive represented by chemical formula 1, for use in a rechargeable lithium battery, and an electrolyte solution including same; wherein X1 to X5 are each independently a halogen atom or a halogen-containing group; and Z is represented by *-NR1R2.