Double-Coated Prussian Blue Cathode for Moisture-Stable Sodium-Ion Batteries
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Solution Overview
Problem
Prussian Blue cathode materials for sodium-ion batteries are hygroscopic, leading to poor processability and storage performance, as well as safety concerns due to side reactions with the electrolyte and gas generation.
Innovation Solution
A cathode material is developed by coating a Prussian Blue substrate with two layers: a tannic acid polymer layer and a hydrophobic layer composed of materials like hexadecylamine or octadecylamine, which suppresses hygroscopicity without affecting electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Prussian Blue is prepared by simple chemical precipitation method, then the cathode material can be easily prepared with low cost, but the material structure contains vacancy defects and crystalline water leading to hygroscopicity
Solution Approach 1:
The patent applies preliminary action by conducting high-temperature heat treatment (dehydration treatment) on the Prussian Blue cathode material before electrode manufacturing processes. This preliminary dehydration removes crystalline water from the material structure in advance, preventing subsequent hygroscopicity and storage stability issues during electrode fabrication and battery assembly processes.
2Ease of operation
If Prussian Blue undergoes air exposure during manufacturing processes, then the material can be processed into electrode sheets, but the hygroscopic nature causes moisture absorption affecting sodium storage performance
Solution Approach 1:
The patent applies preliminary action by performing dehydration treatment on the Prussian Blue material before electrode manufacturing processes that require air exposure. This advance dehydration prevents moisture absorption during subsequent handling, coating, rolling, and assembly operations, ensuring both processability and maintained sodium storage performance throughout manufacturing.
3Ease of operation
If Prussian Blue absorbs moisture during manufacturing, then the material remains processable, but side reactions with electrolyte and gas generation affect battery safety
Solution Approach 1:
The patent applies preliminary action by conducting dehydration treatment on the Prussian Blue cathode material before electrode manufacturing and battery assembly. This preliminary removal of crystalline water prevents subsequent moisture-related harmful effects including side reactions with electrolyte and gas generation during battery operation, thereby ensuring battery safety while maintaining processability.
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 double-layer coated cathode material significantly improves storage stability and electrochemical performance in humid environments, ensuring excellent cycling and rate performance of sodium-ion batteries.
Implementation Method 1
a material forming the second coating layer includes at least one of hexadecylamine, octadecylamine, octadecyl phosphate, N-phenyl-bis(trifluoromethanesulfonimide), 1H,1H,2H,2H-perfluorodecyl triethoxysilane, and 1H,1H,2H,2H-perfluorodecanethiol
Data Source
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AI summary
The present invention relates to the field of sodium ion battery technology, in particular, to a cathode material, a preparation method thereof, and a sodium ion battery. The present invention relates to a cathode material including a Prussian Blue substrate, and a first coating layer and a second coating layer successively coated on the surface of the Prussian Blue substrate; a material forming the first coating includes a polymer of tannic acid; a material forming the second coating layer includes at least one of hexadecylamine, octadecylamine, octadecyl phosphate, N-phenyl-bis(trifluoromethanesulfonimide), 1H,1H,2H,2H-perfluorodecyl triethoxysilane, and 1H,1H,2H,2H-perfluorodecanethiol. The cathode material of the present invention effectively solves the problem of hygroscopicity of Prussian Blue cathode material and effectively improves the storage property and electrochemical performance of the cathode material in air.