Nitrile-Based Battery Electrolyte for Low-Viscosity High Salt Loading
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Solution Overview
Problem
Existing lithium secondary batteries face issues with increased viscosity and surface tension when using high concentration lithium salts, leading to decreased electrode and separator impregnability, prolonged activation process times, and increased process costs, while also experiencing performance degradation due to polarization phenomena.
Innovation Solution
A non-aqueous electrolyte comprising a compound represented by Formula 1, a nitrile-based solvent, and a lithium salt, with specific ratios and additives to maintain low viscosity and surface tension, enhancing electrode and separator impregnability and improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentration lithium salt is used, then ionic conductivity is improved, but viscosity and surface tension increase leading to decreased impregnability
Solution Approach 1:
The patent introduces a fluorinated ether compound with specific molecular structure (R1-O-CH2-R2 where R1 and R2 are fluorinated alkyl groups) to modify the physical parameters of the electrolyte system. This compound reduces the viscosity and surface tension of the high concentration lithium salt solution, enabling proper impregnability of electrodes and separators while preserving the high ionic conductivity provided by the concentrated lithium salt
Solution Approach 2:
The electrolyte is formulated as a composite system combining high concentration lithium salt (1.0 M or higher) with fluorinated ether compound and nitrile-based solvent. This composite approach allows the system to simultaneously achieve the benefits of high ionic conductivity from concentrated salt and the flow/impregnation properties from the fluorinated ether additive
2Power
If high concentration lithium salt is used, then output characteristics are improved, but activation process time is prolonged
Solution Approach 1:
The fluorinated ether compound modifies the rheological parameters of the electrolyte, reducing viscosity to enable faster penetration into electrode and separator structures during activation. This allows the battery to achieve proper impregnability and functional activation more quickly while maintaining the high output characteristics provided by the concentrated lithium salt
3Quantity of substance
If high concentration lithium salt is used, then energy density is improved, but polarization phenomenon increases
Solution Approach 1:
The fluorinated ether compound reduces the viscosity of the electrolyte, which improves the diffusion rate of lithium ions. This enhanced ion transport mitigates the polarization phenomenon that occurs during high current operation, allowing the battery to maintain both high energy density from concentrated salt and acceptable polarization characteristics
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 improves output characteristics, reduces activation process time, and enhances the stability and safety of lithium secondary batteries by maintaining ionic conductivity and impregnability, while ensuring high energy density and reduced corrosion.
Implementation Method 1
maintaining low viscosity and surface tension, enhancing electrode and separator impregnability
Implementation Method 2
a non-aqueous electrolyte that becomes a medium for transferring the lithium ions
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates to a non-aqueous electrolyte for a lithium secondary battery, which includes a compound represented by Formula 1, an organic solvent containing a nitrile-based solvent in an amount of 90 vol% to 100 vol%, and a lithium salt, wherein an amount of the compound represented by Formula 1 is in a range of 2 wt% to 50 wt% based on a total weight of the non-aqueous electrolyte, and a lithium secondary battery including the non-aqueous electrolyte.