Hydrotalcite Purifier for HF Removal in Li-Ion Battery Electrolyte
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Solution Overview
Problem
The existing methods for manufacturing lithium-ion secondary batteries fail to completely prevent water contamination, leading to hydrogen fluoride generation and electrode corrosion, which limits battery performance and requires costly humidity control measures.
Innovation Solution
A purification system comprising a sequential arrangement of a purifier containing synthetic hydrotalcite for hydrogen fluoride removal and a separate purifier for water removal, using adsorbents like activated alumina or synthetic zeolites, to reduce hydrogen fluoride and water concentrations in the electrolyte solution without adding additional adsorbents to the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a material for adsorbing hydrogen fluoride is mixed into the electrolyte solution, then hydrogen fluoride removal is improved, but the per-weight amount of electrode active material is reduced and initial discharge capacity is limited
Solution Approach 1:
The invention separates the hydrogen fluoride removal function from the electrode material by introducing a dedicated purifier containing synthetic hydrotalcite into the electrolyte solution circulation path. This segmentation allows the electrode material to maintain its full active material content while the purifier handles HF removal independently, resolving the contradiction between HF removal effectiveness and electrode active material quantity.
Solution Approach 2:
The synthetic hydrotalcite in the purifier acts as an intermediary substance that selectively adsorbs hydrogen fluoride from the electrolyte solution without interfering with the electrode active material. This intermediary approach enables HF removal while preserving the full capacity of the electrode materials, avoiding the need to mix adsorbents directly with the electrodes.
2Object-affected harmful factors
If manufacturing is performed in a controlled environment with reduced humidity, then water contamination is reduced, but production costs increase
Solution Approach 1:
The invention implements preliminary water removal by connecting a water adsorbent purifier upstream before the hydrogen fluoride purifier. This preliminary action reduces water content in the electrolyte before HF removal, preventing water-related issues without requiring expensive controlled humidity environments throughout the manufacturing process, thus resolving the contradiction between water contamination control and production cost.
3Reliability
If fluoride-based electrolytes are used for good conductivity and potential window, then battery performance is improved, but hydrolysis releases hydrogen fluoride that dissolves electrode materials and corrodes current collector
Solution Approach 1:
The invention converts the harmful effect of hydrogen fluoride generation through hydrolysis into a manageable issue by using the synthetic hydrotalcite purifier to selectively adsorb HF from the electrolyte. The purifier transforms the harmful HF byproduct into an adsorbed state within the purifier's layered structure, allowing the battery to maintain the benefits of fluoride-based electrolytes (good conductivity and potential window) while eliminating the corrosive effects on electrode materials and current collector.
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
This approach effectively reduces hydrogen fluoride and water levels in the electrolyte solution, enhancing battery performance and longevity while reducing manufacturing costs by minimizing the need for moisture control measures.
Implementation Method 1
These hydrotalcite compounds have a layered structure, and act to adsorb and fix hydrogen fluoride molecules and sometimes water molecules between layers
Implementation Method 2
a purifier for removing water, which contains a water adsorbent
Data Source
Figure 1~2(b)
AI summary
The present invention is a purification system for removing hydrogen fluoride and water from an electrolytic solution for lithium-ion secondary batteries in which [1] a purifier for removing hydrogen fluoride containing a hydrogen fluoride adsorbent selected from among carbonate hydrotalcites and calcined hydrotalcites and [2] a purifier for removing water containing an adsorbent for trapping water are connected in this order from upstream to downstream.