Surface Fluorination of Battery Materials With Mild Reactive Gases
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Solution Overview
Problem
Existing battery materials, particularly cathode, anode, and electrolyte components, suffer from surface degradation and corrosion issues during electrochemical cycling, leading to capacity and voltage fading, and current collectors are prone to corrosion due to lack of fluoride ions in solid electrolytes, necessitating improved surface protection and fluorination methods for scalability and homogeneity.
Innovation Solution
A method involving a vertically oriented flow-type tube reactor for surface fluorination of battery materials using mild fluorinating agents like HCFs, PFCs, HCFCs, and CFCs under controlled temperature and gas flow, allowing for precise and scalable nanometer-sized fluoride coating of cathode, anode, and electrolyte materials, enhancing their stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fluorinating agents (HF, F2) are used for surface fluorination, then fluorination effectiveness is improved, but safety and process controllability deteriorate due to toxicity and corrosiveness
Solution Approach 1:
The patent introduces mild fluorinating agents (HCFs, PFCs, HCFCs, CFCs) as intermediary substances that can transfer fluorine atoms to battery material surfaces without exhibiting the extreme toxicity and corrosiveness of traditional fluorinating agents like HF and F2. These intermediary agents achieve the desired fluorination effect while significantly improving safety and process controllability.
Solution Approach 2:
The patent changes the chemical parameters of the fluorinating agents from highly reactive and hazardous substances (HF, F2) to milder fluorinated hydrocarbons with controlled reactivity. This parameter change allows for safer handling, better process control, and reduced harmful effects while maintaining fluorination effectiveness.
2Reliability
If surface coating with inorganic materials is applied to protect cathode materials, then surface degradation is mitigated, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the protective function from complex multi-layer inorganic coatings and achieves it through a simpler molecular-level fluorination process. By introducing fluorine atoms directly into the surface structure of battery materials, the patent creates a protective effect without requiring separate coating layers, thereby simplifying the manufacturing process.
Solution Approach 2:
The patent creates composite structures at the molecular level by incorporating fluorine into the surface chemistry of battery materials. This molecular composite approach provides surface protection through altered chemical properties rather than physical coating layers, reducing manufacturing complexity.
3Reliability
If bulk doping with fluoride ions is performed to improve stability, then electrochemical performance is enhanced, but manufacturing precision and control become more difficult
Solution Approach 1:
The patent applies fluorination locally at the surface of battery materials rather than throughout the bulk. This localized surface fluorination achieves the desired stability enhancement while avoiding the manufacturing control issues associated with uniform bulk doping. The fluorine concentration is high at the surface where it is most needed for protection, with minimal fluoride content in the bulk.
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 method achieves uniform nanometer-sized surface fluoride coating, improving specific capacity retention, cycling performance, and mitigating corrosion, with mild fluorinating agents offering a safer and more controllable process compared to toxic gases like HF and F2, while enabling adaptation for industrial scalability.
Implementation Method 1
a method for preparing a nanometer-sized surface fluorinated battery material... fluorinating the surface of the battery material at controllable temperature using a mild fluorinating agent or a mixture thereof
Implementation Method 2
under a fluorinating gas or gas mixtures flow that is flooding the inner volume of the tube-type reactor at controllable flow rates
Implementation Method 3
heating the battery material to the desired extent in the range of 25 to 800° C. under an inert gas atmosphere supplied by at least a first gas supply line
Data Source
AI summary
A method uses mild fluorinating agents, such as hydrofluorocarbons—HCFs, perfluorocarbons—PFCs, hydrochlorofluorocarbons HCFCs and chlorofluorocarbons—CFCs, to fine-tune the fluorination process in battery material preparation in order to obtain uniform nanometer-sized surface fluoride coated battery materials. The use of a vertical flow-type tube reactor permits a fine-tuning of the fluorination process by accurately regulating the active gas or mixture of gases flow over battery materials using mass-flow regulators, and precisely setting the temperature with vertical rube furnace. Additionally, these fluorinating agents have slightly different reactivity, decomposing and reacting with battery materials at different temperatures, and therefore, offering additional parameter of fluorination fine-tuning. The method is scalable and can be easily adapted as an industrial solution. Moreover, all these gases are non-toxic, non-corrosive and non-flammable gases at room temperatures, hence, they are more convenient to handle than highly-toxic and highly-corrosive HF and F2 gases.