Non-aqueous Electrolyte Surfactant Viscosity Reduction
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Solution Overview
Problem
High-concentration lithium secondary batteries face limitations in ion conductivity due to increased viscosity and surface tension when using high-concentration electrolytes, which affects battery performance and separator wettability.
Innovation Solution
A non-aqueous electrolyte with a lithium salt concentration of 4.1 M or more, combined with an organic solvent and a surfactant, specifically a fluorine-based surfactant, to reduce viscosity and surface tension, thereby improving ion conductivity and separator wettability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-concentration electrolytic salt is used to increase ion conductivity, then the amount of ions in electrolyte increases and ion conductivity improves, but viscosity and surface tension increase remarkably causing degradation of battery performance
Solution Approach 1:
A surfactant is introduced as an intermediary substance to mediate between the high-concentration electrolytic salt and the battery components. The surfactant reduces surface tension and viscosity of the electrolyte, enabling better wettability of the separator while maintaining high ion conductivity, thus resolving the contradiction between improved reliability and reduced harmful effects
Solution Approach 2:
The patent changes the concentration parameter of electrolytic salt to 1.1 M or more (preferably 1.3 M to 1.8 M) and combines it with surfactant addition, transforming the electrolyte's physical properties to achieve both high ion conductivity and acceptable viscosity/surface tension levels
2Reliability
If electrolytic salt concentration is increased to improve battery performance, then ion conductivity increases, but wettability of separator deteriorates
Solution Approach 1:
The surfactant acts as a mediator that improves the interaction between the high-concentration electrolyte and the separator. By reducing surface tension, the surfactant enables the electrolyte to wet the separator effectively even at high concentrations, thus maintaining ease of operation while achieving high reliability
Solution Approach 2:
The patent creates a composite electrolyte system combining electrolytic salt, organic solvent, and surfactant. This composite formulation achieves synergistic effects where the surfactant component compensates for the reduced wettability caused by high salt concentration, maintaining both high ion conductivity and good separator wettability
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 solution enhances battery performance by increasing ion conductivity and preventing degradation in viscosity and surface tension, resulting in a secondary battery with improved charge/discharge characteristics and stability.
Implementation Method 1
a non-aqueous electrolyte including a lithium salt having a concentration of 4.1 M or more, an organic solvent, and a surfactant
Data Source
Figure 1
AI summary
The present invention relates to a non-aqueous electrolyte for lithium secondary battery, and more particularly, to a non-aqueous electrolyte including a lithium salt having a concentration of 4.1 M or more, an organic solvent, and a surfactant.