Sodium iron phosphate pyrophosphate positive-electrode material and preparation method thereof, battery, and energy storage device
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Solution Overview
Problem
Existing sodium iron phosphate pyrophosphate (Na4Fe3(PO4)2(P2O7) materials exhibit low compacted density due to the formation of impurity phases and mismatched molar ratios, which affect sphericity and capacity.
Innovation Solution
Control the molar ratio of sodium to iron in the sodium iron phosphate pyrophosphate positive-electrode material to 1.36≤A≤1.45, and optimize particle size distribution and sphericity through spray-drying and sintering processes to minimize impurity phases and enhance compacted density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If existing sodium iron phosphate pyrophosphate material is used, then the material structure is formed, but the compacted density is low
Solution Approach 1:
The patent optimizes the molar ratio parameters of raw materials (Na/Fe ratio controlled at 1.36-1.45, Na/P ratio controlled at 1.02-1.05) to minimize impurity phases and maximize sphericity. This parameter optimization directly addresses the contradiction by achieving both high compacted density and high sphericity through precise compositional control during synthesis
Solution Approach 2:
The patent applies local quality optimization by controlling the distribution and morphology of particles through spray-drying parameters. The process creates uniform spherical particles with specific size distribution (D50: 8-15 μm), ensuring local optimality in particle morphology that contributes to both high sphericity and high compacted density
2Manufacturing precision
If impurity phases are present, then the material can be synthesized, but the sphericity and capacity are reduced
Solution Approach 1:
The patent changes the chemical composition parameters by precisely controlling the molar ratios of sodium, iron, and phosphorus in the raw materials. By maintaining Na/Fe ratio at 1.36-1.45 and Na/P ratio at 1.02-1.05, the synthesis process minimizes impurity phase formation while maximizing sphericity, directly resolving the contradiction between material synthesis and purity
Solution Approach 2:
The patent implements feedback control through systematic optimization of synthesis parameters based on observed impurity formation. The preparation method adjusts spray-drying and sintering conditions to suppress impurity phases, using the relationship between processing parameters and impurity formation as a feedback mechanism to achieve high sphericity
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 optimized material achieves higher sphericity and compacted density, improving processability and electrochemical performance in sodium-ion batteries.
Implementation Method 1
The slurry is spray-dried to obtain a precursor powder
Implementation Method 2
The precursor powder is sintered to obtain the sodium iron phosphate pyrophosphate positive-electrode material
Data Source
AI summary
A sodium iron phosphate pyrophosphate positive-electrode material and a preparation method thereof, a battery, and an energy storage device are provided. A molar ratio A of sodium element to iron element in the sodium iron phosphate pyrophosphate positive-electrode material of embodiments of the disclosure satisfies 1.36≤A≤1.45.