Lithium Battery Electrolyte Additive for High-Concentration Wettability
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Solution Overview
Problem
Existing electrolytes with high concentrations of lithium salt or high-boiling point solvents exhibit low wettability to electrodes and separators, leading to increased activation processing time, cost, and adverse effects on battery life and performance.
Innovation Solution
A non-aqueous electrolyte for lithium secondary batteries containing a wettability-improving additive with a trifluoromethylsulfonyl group, such as 1H,1H,5H-octafluoropentyl trifluoromethanesulfonate, is used to enhance electrode and separator wettability, even with high lithium salt concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentration of lithium salt or high-boiling point solvent is used in electrolyte, then heat resistance and electrochemical stability are improved, but wettability to electrode and separator deteriorates
Solution Approach 1:
A wettability-improving additive is introduced as an intermediary substance between the high-concentration lithium salt electrolyte and the electrode/separator. This additive has a fluorinated structure that reduces surface tension and improves wettability without compromising the heat resistance and electrochemical stability provided by the high-concentration lithium salt or high-boiling point solvent.
Solution Approach 2:
The chemical structure of the additive is designed with specific fluorinated groups that change the surface tension parameters of the electrolyte. By adjusting the fluorinated structure parameters, the electrolyte achieves both high wettability and maintained thermal stability.
2Reliability
If high concentration of lithium salt or high-boiling point solvent is used in electrolyte, then electrochemical stability is improved, but affinity to electrode and separator deteriorates
Solution Approach 1:
The wettability-improving additive acts as a mediator that enhances the interaction between the electrolyte and electrode/separator surfaces. The fluorinated structure of the additive provides good affinity to these surfaces while allowing the bulk electrolyte to maintain its high electrochemical stability.
3Ease of manufacture
If polyolefin-based separator and PVDF binder electrode are used, then general battery structure is achieved, but wettability with high-concentration electrolyte deteriorates
Solution Approach 1:
The wettability-improving additive serves as an intermediary that bridges the compatibility between conventional battery materials (polyolefin separator and PVDF binder) and high-concentration lithium salt electrolytes. The additive's fluorinated structure specifically targets improving wetting of these conventional materials.
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 additive reduces surface tension, improving wettability and preventing degradation of electrochemical properties, thus enhancing battery performance and reducing manufacturing complexity and costs.
Implementation Method 1
incorporating a wettability-improving additive with a trifluoromethylsulfonyl group, which reduces surface tension and improves electrode assembly wettability
Data Source
AI summary
An electrolyte for a lithium secondary battery including a wettability-improving additive having a trifluoromethylsulfonyl group. The electrolyte has reduced surface tension to improve the wettability of an electrode assembly with the electrolyte. Therefore, it is possible to ensure high electrolyte wettability even when the electrolyte includes a high-boiling point solvent or a high concentration of lithium salt.