Potassium Imide Electrolyte for Fast-Charging Lithium Batteries
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Solution Overview
Problem
Rechargeable lithium batteries face challenges with high-rate charging, as it can lead to deteriorated lifecycle characteristics and increased resistance due to lithium dendrite formation on the negative electrode surface.
Innovation Solution
An electrolyte composition for rechargeable lithium batteries is developed, incorporating a non-aqueous organic solvent, a lithium salt, and a potassium imide salt, which forms a lithiophilic film on the negative electrode, reducing dendrite formation and enhancing high-rate charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-rate charging is performed, then charging speed is improved, but lifecycle characteristics deteriorate and resistance increases due to lithium dendrite formation
Solution Approach 1:
The patent introduces a potassium imide salt as an intermediary substance in the electrolyte composition. This salt acts as a mediator that facilitates high-rate charging while preventing lithium dendrite formation, thereby resolving the contradiction between charging speed and battery reliability. The potassium imide salt specifically addresses the harmful effect of dendrite precipitation without compromising charging performance.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating potassium imide salt at specific concentrations (0.1-5 wt%). This parameter change transforms the electrolyte's properties to enable both high-rate charging and dendrite suppression, simultaneously improving charging speed while maintaining lifecycle characteristics.
2Speed
If high-rate charging is performed, then charging speed is improved, but resistance increases due to lithium dendrite formation
Solution Approach 1:
The potassium imide salt serves as an intermediary that prevents the formation of lithium dendrites on the negative electrode surface. By blocking dendrite formation, it prevents the associated increase in resistance, allowing high-rate charging to proceed without the harmful resistance increase that would otherwise occur.
Solution Approach 2:
The patent converts the potential harm of rapid charging (which causes dendrite formation and resistance increase) into a benefit by using potassium imide salt to suppress dendrite formation. The rapid charging process itself is maintained, but the harmful byproduct (dendrites) is eliminated through the electrolyte modification.
3Ease of manufacture
If conventional electrolyte is used, then manufacturing is simple, but high-rate charging performance is poor due to lithium dendrite precipitation
Solution Approach 1:
The patent creates a composite electrolyte system by combining conventional electrolyte components (cyclic carbonate, chain carbonate, lithium salt) with potassium imide salt. This composite approach maintains the simplicity of conventional electrolyte preparation while adding the functional benefits of potassium imide salt to enable high-rate charging performance.
Solution Approach 2:
The patent modifies the electrolyte composition by adding potassium imide salt at optimized concentrations (0.1-5 wt%). This parameter change enhances the electrolyte's ability to support high-rate charging while maintaining ease of manufacture, as the addition process follows conventional electrolyte preparation methods.
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 electrolyte composition improves high-rate charging performance while minimizing the deterioration of lifecycle characteristics and resistance increase, leading to a more stable and efficient lithium battery operation.
Implementation Method 1
the potassium imide salt may be or include KFSI (potassium bis(fluorosulfonyl)imide), KTFSI (potassium bis(trifluoromethanesulfonyl)imide), KFTFSI (potassium (fluorosulfonyl) (trifluoromethanesulfonyl)imide), or a combination thereof
Implementation Method 2
the potassium imide salt content may be or include about 0.15 to about 1.0 wt % based on 100 wt % of the electrolyte for a rechargeable lithium battery
Implementation Method 3
a positive electrode that has a positive electrode active material that can intercalate and de-intercalate lithium, and a negative electrode that has a negative electrode active material that can intercalate and de-intercalate lithium
Implementation Method 4
A rechargeable lithium battery may be recharged and has three or more times as high energy density per unit weight as a conventional lead storage battery
Data Source
AI summary
Examples of this disclosure relate to an electrolyte for a rechargeable lithium battery, and a rechargeable lithium battery including the same, the electrolyte including a non-aqueous organic solvent, a lithium salt, and a potassium imide salt.