Ionic Liquid Electrolyte for Safe Anode-Free Batteries
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Solution Overview
Problem
Lithium batteries using organic carbonates as electrolytes face safety issues due to flammability, leading to potential fires and explosions from overcharging or overheating, necessitating a safer alternative.
Innovation Solution
Development of electrolytes based on ionic liquids with organic nitrogen cations and charge-delocalized organic anions, combined with alkali or alkaline earth metal salts, which provide improved ionic conductivity, safety, and stability, including the use of polymers and additives like organic carbonates to enhance performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic carbonates are used as electrolytes in lithium batteries, then ionic conductivity and battery performance are improved, but safety deteriorates due to flammability leading to fires and explosions
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using ionic liquids with specific cation-anion combinations (e.g., imidazolium, pyrrolidinium cations with BF4-, PF6-, TFSI- anions) instead of organic carbonates. This parameter change fundamentally alters the flammability characteristic while maintaining ionic conductivity through optimized salt concentration (0.5-5.0 M) and composition ratios.
Solution Approach 2:
The patent creates a composite electrolyte system by combining ionic liquids with electrolyte salts (LiPF6, LiBF4, LiTFSI, etc.) to form a new composite material that exhibits both the safety benefits of ionic liquids and the high ionic conductivity of salt-based electrolytes. The composite structure allows synergistic effects where the ionic liquid provides safety and the salt provides conductivity.
2Object-generated harmful factors
If ionic liquids are used as electrolytes, then safety is improved by preventing fires and explosions, but ionic conductivity may deteriorate compared to organic carbonates
Solution Approach 1:
The patent optimizes ionic conductivity by carefully controlling the concentration of electrolyte salts (0.5-5.0 M range) and selecting specific ionic liquid compositions with appropriate cation-anion pairs. The parameter optimization ensures that the viscosity and ionic mobility are balanced to achieve conductivity levels sufficient for practical battery operation while maintaining the safety advantages of ionic liquids.
Solution Approach 2:
The composite electrolyte system combines the safety benefits of ionic liquids with the high conductivity of electrolyte salts. The ionic liquid component provides fire resistance and thermal stability, while the dissolved salt components (LiPF6, LiBF4, etc.) provide the necessary ionic conductivity for efficient charge and discharge performance.
3Duration of action of stationary object
If conventional electrolytes are used, then manufacturing simplicity is maintained, but battery life and stability deteriorate due to safety issues and degradation
Solution Approach 1:
The patent extends battery life by changing the electrolyte composition to ionic liquids which provide superior thermal stability and electrochemical stability. These parameter changes prevent decomposition and safety incidents that would otherwise limit battery lifespan, enabling longer operational duration and improved cycle life even though the electrolyte formulation becomes more complex.
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 ionic liquid electrolytes offer enhanced safety by preventing fires and explosions, maintaining high ionic conductivity, and extending battery life, with improved charging/discharging rates and stability at high temperatures, making them suitable for lithium metal and ion batteries.
Implementation Method 1
The electrolyte includes an ionic liquid and an electrolyte salt dispersed in the ionic liquid
Implementation Method 2
a thermal gelation process is performed to form the anode-free rechargeable battery
Data Source
AI summary
An electrolyte includes an ionic liquid and an electrolyte salt dispersed in the ionic liquid. The ionic liquid includes organic nitrogen cations and charge-delocalized organic anions. The electrolyte salt is selected from alkali metal salt and/or alkaline earth metal salt.