Iron Phosphate Cathode Synthesis Through Viscosity-Controlled Grinding
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Solution Overview
Problem
The high cost and environmental pollution associated with synthesizing Na4Fe3(PO4)2P2O7 for sodium ion batteries, due to the use of water-soluble salts, hinder its industrialization and large-scale energy storage applications.
Innovation Solution
A method involving the controlled regulation of solution viscosity through a specific solid-liquid ratio during grinding, followed by drying and sintering, to produce a homogeneous iron-based composite phosphate cathode material with uniform nano-spherical particles, reducing the environmental impact and synthesis costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water-soluble salts are used in the synthesis process of Na4Fe3(PO4)2P2O7, then the material can be synthesized with good electrochemical performance, but the process cost increases and environmental pollution occurs due to decomposition products
Solution Approach 1:
The patent changes the physical state parameter of reactants from solid water-soluble salts to liquid organic carboxylic acids. This parameter change eliminates the need for water as a solvent, preventing water decomposition products from causing environmental pollution. The organic carboxylic acid reactants are incorporated into the final product structure, avoiding harmful decomposition byproducts while maintaining good electrochemical performance.
2Ease of manufacture
If water-soluble salts are used in the synthesis process of Na4Fe3(PO4)2P2O7, then the material can be synthesized, but the synthesis cost increases due to the need for water removal and decomposition product management
Solution Approach 1:
The patent extracts and eliminates water as a solvent from the synthesis system, replacing it with anhydrous organic carboxylic acids. This extraction of water removes the need for energy-intensive drying processes and eliminates costs associated with managing water decomposition products, significantly reducing overall synthesis costs while maintaining ease of manufacture.
Solution Approach 2:
The patent uses readily available organic carboxylic acids (such as acetic acid, propionic acid, butyric acid) as reactants. These inexpensive, commercially available materials replace expensive water-soluble salts and eliminate the need for complex purification and waste management processes, reducing both material and processing costs.
3Manufacturing precision
If solid reactants are ground together, then homogeneous mixing can be achieved, but the reaction efficiency is limited by solid-state diffusion
Solution Approach 1:
The patent employs liquid organic carboxylic acids as reactants instead of solid materials. The liquid state enables superior mixing and contact between reactants during the grinding process, achieving homogeneous distribution of all components throughout the mixture. This liquid-phase approach dramatically enhances reaction efficiency compared to solid-state diffusion by allowing reactants to move and interact more freely during processing.
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 results in an iron-based composite phosphate cathode material with excellent electrochemical performance, improved cycle stability, and safe performance in sodium ion batteries, facilitating their use in large-scale energy storage systems.
Implementation Method 1
The first mixed system is ground to obtain a second mixed system
Implementation Method 2
the first mixed system is ground to obtain a second mixed system, and then same are dried and sintered
Implementation Method 3
the first mixed system is ground to obtain a second mixed system, and then same are dried and sintered
Data Source
AI summary
The present disclosure relates to an iron-based composite phosphate cathode material and a preparation method thereof, and a cathode plate and a sodium ion battery. The method for preparing an iron-based composite phosphate cathode material includes: uniformly mixing a sodium source, a phosphorus source, a carbon source, and water, and then mixing same with iron phosphate to obtain a first mixed system; and grinding the first mixed system to obtain a second mixed system, and then drying and sintering same. In the first mixed system, the total mass of Na element, Fe element, (PO4)3−, and the carbon source is 30%-40% of the mass of the water; and the viscosity of the second mixed system is greater than or equal to 300 Pa·S. According to the method, a solid reactant can be solubilized during grinding, the iron-based composite phosphate cathode material is uniformly sized nano spherical particles.