Rechargeable Lithium Battery Electrolyte for Dendrite-Stable Fast Charging
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Solution Overview
Problem
Rechargeable lithium batteries face challenges with lithium dendrite formation and safety issues during high-voltage and high-rate charging, leading to reduced cycle-life and safety concerns due to side reactions and poor performance of existing electrolytes.
Innovation Solution
An electrolyte composition including a non-aqueous organic solvent, a lithium salt, and additives such as a fluorinated ketone and an Ag salt is used to improve impregnability and uniform lithium ion intercalation on the negative electrode, suppressing lithium dendrite growth and enhancing safety and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high voltage (4.5V or higher) and high-rate charging are used to increase energy density and charging speed, then productivity and energy density are improved, but lithium dendrite growth and side reactions increase, deteriorating reliability and safety
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance in the electrolyte that mediates between the electrode and electrolyte interface. This compound forms a protective interface layer that enables high-rate charging while preventing lithium dendrite growth and side reactions, thus maintaining reliability under high productivity conditions
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating specific fluorinated cyclic carbonate compounds with defined molecular structures (Formula 1 and Formula 2). These parameter changes in electrolyte composition enable the system to achieve both high charging rates and maintained cycle-life through improved interfacial properties
2Ease of operation
If ester-based solvents with low viscosity are used to improve electrolyte impregnability and suppress lithium dendrite, then ease of operation is improved, but oxidation resistance decreases and inflammability increases, worsening reliability and safety
Solution Approach 1:
The patent creates a composite electrolyte system by combining fluorinated cyclic carbonate compounds with other electrolyte components. This composite approach achieves both low viscosity for good impregnability and high oxidation resistance for reliability, while the fluorinated structure provides inherent flame retardancy
Solution Approach 2:
The patent applies local quality by using fluorinated cyclic carbonate compounds that specifically modify the electrode interface properties. The fluorinated groups provide localized oxidation resistance and flame retardancy at the critical electrode-electrolyte interface, while the overall electrolyte maintains low viscosity for good impregnability
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 effectively reduces lithium dendrite formation, improves high-rate charging performance, and enhances high-temperature cycle-life characteristics and stability of rechargeable lithium batteries, ensuring improved safety and performance under harsh conditions.
Implementation Method 1
improving the impregnation of the negative electrode
Implementation Method 2
uniformizing the intercalation of lithium ions on the surface of the negative electrode
Implementation Method 3
suppressing the generation of lithium dendrites in the negative electrode
Data Source
AI summary
An electrolyte for a rechargeable lithium battery, and rechargeable lithium battery including the same are disclosed. The electrolyte includes a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive includes a fluorinated ketone and an Ag salt.