Lithium Battery Electrolyte Additive for Transition Metal Suppression
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Solution Overview
Problem
Rechargeable lithium batteries face challenges with reduced performance due to transition metal ion elution and precipitation, leading to decreased storage capacity, capacity retention, and increased gas generation during high-temperature storage.
Innovation Solution
The use of an electrolyte formulation that includes a lithium salt, a non-aqueous organic solvent, and an additive represented by Formula 1, which effectively controls moisture to suppress transition metal ion elution and precipitation, thereby maintaining battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte formulations are used, then basic battery operation is maintained, but transition metal ion elution and precipitation occur during high-temperature storage, leading to reduced capacity retention and increased gas generation
Solution Approach 1:
The patent introduces a specific additive (Formula 1 with isocyanate groups) as an intermediary substance between the transition metal ions and the electrolyte environment. This additive acts as a complexing agent that binds to transition metal ions, preventing their elution from the positive electrode and subsequent precipitation, thereby resolving the contradiction between maintaining basic operation and preventing ion elution during high-temperature storage
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating specific additives with isocyanate groups (NCO) at controlled concentrations (0.01-5 wt%). This parameter change transforms the electrolyte's chemical environment, enabling it to suppress transition metal ion elution through complex formation, thus improving capacity retention without compromising basic battery operation
2Reliability
If conventional electrolyte formulations are used, then battery charge/discharge cycles proceed normally, but gas generation increases during high-temperature storage, affecting battery safety and performance
Solution Approach 1:
The additive in Formula 1 serves as a mediating substance that interacts with transition metal ions to form stable complexes. This intermediary action prevents the decomposition reactions that would otherwise generate gas during high-temperature storage, thereby improving storage stability while suppressing harmful gas generation
Solution Approach 2:
The patent converts the potentially harmful interaction between transition metal ions and electrolyte (which causes gas generation) into a beneficial complex formation process. The additive captures transition metal ions through complexation, transforming a harmful elution-precipitation-gas generation pathway into a stable complex formation pathway, thus eliminating gas generation while maintaining battery functionality
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 proposed electrolyte solution significantly improves the battery's performance by maintaining capacity retention and reducing gas generation during charge/discharge cycles and high-temperature storage, ensuring stable and efficient battery operation.
Implementation Method 1
effectively controls moisture to suppress transition metal ion elution and precipitation
Implementation Method 2
electrical energy is generated due to oxidation and reduction reactions when lithium ions are intercalated and de-intercalated
Data Source
AI summary
An electrolyte for a rechargeable lithium battery includes a lithium salt, a non-aqueous organic solvent, and an additive represented by Formula:where at least one R1 is an isocyanate group and at least one R2 is an isocyanate group.