Ceramic HF Scavengers for Cathode Transition Metal Dissolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face transition metal dissolution at elevated temperatures due to hydrofluoric acid (HF) formation, leading to cathode active material loss and reduced battery performance, as conventional HF scavengers release water and exacerbate the issue.
Innovation Solution
Incorporating ceramic hydrofluoric acid (HF) scavengers like Li2SiO3, LiAlO2, or Li2O—Al2O3—SiO2 into electrode coatings or embedding them within electrode active materials to trap protons without forming hydrates, preventing HF-related degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional HF scavengers (SiO2 and Al2O3) are used to scavenge HF, then HF scavenging is achieved, but water is released at elevated temperatures promoting further hydrolysis of LiPF6
Solution Approach 1:
The patent changes the chemical composition parameters of the HF scavenger from conventional SiO2 and Al2O3 to lithium-containing ceramics (Li2SiO3, LiAlO2, Li2O-Al2O3-SiO2). This parameter change enables the scavenger to consume HF without releasing water, as the lithium-containing compounds react with HF to form stable lithium fluoride and water-free products, thus resolving the contradiction between HF scavenging and water release
Solution Approach 2:
The patent employs composite ceramic materials containing lithium oxide, silicon dioxide, and aluminum oxide in specific ratios. These composite materials combine the HF scavenging capability with the property of not releasing water at elevated temperatures, achieving both requirements simultaneously through material composition design
2Stability of the object's composition
If transition metal dissolution is prevented by removing water sources, then cathode stability is improved, but HF formation from LiPF6 hydrolysis continues at elevated temperatures
Solution Approach 1:
The lithium-containing ceramic scavenger acts as an intermediary substance between the LiPF6 electrolyte salt and the cathode active material. It intercepts HF before it can reach and dissolve the cathode, providing a protective barrier function. The scavenger absorbs the harmful HF through chemical reaction, preventing it from affecting the cathode stability while being positioned strategically in the electrode structure
3Object-affected harmful factors
If ceramic HF scavengers are embedded within electrode active material, then HF scavenging is enhanced, but electrode fabrication complexity increases
Solution Approach 1:
The patent merges the HF scavenger function with the electrode fabrication process by incorporating the lithium-containing ceramic powder into the electrode slurry mixture. This allows the scavenger to be integrated into the electrode structure during standard coating and drying procedures, avoiding separate complex fabrication steps while maintaining effective HF scavenging distribution throughout the electrode
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 ceramic HF scavengers effectively prevent transition metal dissolution, enhancing battery cycle stability and capacity retention at elevated temperatures by inhibiting HF formation and subsequent reactions with cathode materials.
Implementation Method 1
the ceramic HF scavenger reacts with the HF to form the stable, non-hydrated compounds LiH2SiO4 or LixH4−xSiO4 (0 ≤ x ≤ 2)
Implementation Method 2
The ceramic HF scavenger is in the form of a coating that coats at least a portion of the electrode active material
Data Source
AI summary
An electrode including an electrode active material and a ceramic hydrofluoric acid (HF) scavenger is provided. The ceramic hydrofluoric acid (HF) scavenger includes M2SiO3, MAlO2, M2O—Al2O3—SiO2, or combinations thereof, where M is lithium (Li), sodium (Na), or combinations thereof. Methods of making the electrode are also provided.