Ferroboron-Coated Lithium Iron Phosphate for Lower Interface Resistance
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Solution Overview
Problem
Solid-state batteries face challenges due to high interface impedance and inferior interface compatibility between electrodes, which conventional conductive materials cannot adequately address.
Innovation Solution
A method for preparing ferroboron alloy-coated lithium iron phosphate, involving the preparation of ferrous phosphate and lithium phosphate, followed by grinding, drying, and calcination, with the addition of specific solutions to create a ferroboron alloy coating, thereby reducing interface resistance and improving conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive materials (amorphous carbon) are used to coat lithium iron phosphate, then electrical conductivity is improved, but interface resistance with solid-state electrolytes remains high due to low compacted density and porous structures
Solution Approach 1:
The patent changes the material parameter from conventional amorphous carbon to ferroboron alloy, which has fundamentally different physical and chemical properties including higher density, better conductivity, and superior interface compatibility with solid-state electrolytes
Solution Approach 2:
The patent uses ferroboron alloy as a composite coating material that combines the benefits of high electrical conductivity with high compacted density, eliminating the porous structure problems of carbon-based materials while maintaining conductivity enhancement
2Reliability
If metal coatings are applied to lithium iron phosphate, then conductivity is enhanced, but metal elements are easily eroded by electrolytes and deposited on negative electrode
Solution Approach 1:
The patent employs ferroboron alloy as a composite material that combines iron and boron elements in specific proportions, creating a coating with both high conductivity and excellent corrosion resistance, preventing the erosion and deposition problems associated with pure metal coatings
Solution Approach 2:
The patent optimizes the compositional parameters of the coating by controlling the Fe/B ratio and using controlled atmosphere calcination to create a stable, corrosion-resistant ferroboron alloy structure that maintains integrity in electrolyte environments
3Quantity of substance
If solid-state electrolytes are used to replace liquid electrolytes, then energy density is improved, but interface impedance increases and interface compatibility deteriorates
Solution Approach 1:
The patent applies a specially designed ferroboron alloy coating specifically at the interface between the lithium iron phosphate electrode and the solid-state electrolyte, creating a localized region with optimized properties for both conductivity and interface compatibility without affecting the bulk properties of the electrode material
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 ferroboron alloy coating significantly reduces interface resistance, enhances electronic conductivity, and improves the density and corrosion resistance of the lithium iron phosphate, making it suitable for solid-state battery applications.
Implementation Method 1
The ferroboron alloy coating significantly reduces interface resistance, enhances electronic conductivity
Implementation Method 2
calcining to obtain a calcined material
Data Source
AI summary
The present disclosure relates to a method for preparing ferroboron alloy-coated lithium iron phosphate, comprising: preparing ferrous phosphate and lithium phosphate, then mixing ferrous phosphate and lithium phosphate and adding a hydrazine hydrate solution to obtain a mixture which is then subjected to grinding, drying and then calcining to obtain a calcined material, adding pure water to the calcined material and grinding the calcined material in water to obtain a slurry, to which PEG, ferrous sulfate crystals and disodium EDTA are added and stirred to dissolve, then adding a sodium borohydride solution and a sodium hydroxide solution while stirring and maintaining a pH in the process at 8.5-10.5, reacting for 15-30 min to obtain a product, and filtering, washing and vacuum drying the product to obtain the ferroboron alloy-coated lithium iron phosphate. The method may reduce interface resistance while improving conductivity, corrosion resistance, oxidation resistance and density of the product.