Sodium-Ion Battery Electrode Material Structural Stability
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Solution Overview
Problem
Sodium-ion batteries face challenges with electrode disintegration due to volume changes during charging, leading to reduced cyclic life and lower energy density compared to lithium-ion batteries.
Innovation Solution
Development of an electrode material comprising an oxide with sodium, vanadium, and phosphorus, represented by formulas Nax1V2(PO4)3 and Na3+x2−yV2(PO4−yFy)3, which can be doped with fluorine, along with a manufacturing method involving solvent removal, sintering, and dispersion to enhance structural stability and electric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sodium-ion battery uses conventional electrode materials, then the battery can operate, but the electrode structure disintegrates due to volume changes during charging, leading to reduced cyclic life
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrode material by adjusting the sodium content (x1 between 3.01-3.99) and incorporating fluorine doping (y between 0.01-0.30) into the Na3+xV2(PO4-yFy)3 structure. These parameter changes optimize the material's structural stability while maintaining electrochemical performance, preventing electrode disintegration during charging cycles
Solution Approach 2:
The patent creates a composite electrode material by combining multiple elements (sodium, vanadium, phosphorus, and fluorine) into a unified crystal structure Na3+xV2(PO4-yFy)3. This composite approach integrates the benefits of each element: sodium provides ion conductivity, vanadium offers structural framework, phosphorus ensures stability, and fluorine enhances both structural integrity and electrical properties
2Use of energy by moving object
If sodium-ion battery uses conventional electrode materials, then the battery can function, but the energy density is lower compared to lithium-ion batteries due to reduced reduction potential
Solution Approach 1:
The patent optimizes the reduction potential by adjusting the chemical parameters of the electrode material, specifically controlling the sodium content (x1) and fluorine doping level (y). These parameter adjustments enhance the electron transport capability and reduce potential, thereby increasing energy density while preserving electrochemical performance
Solution Approach 2:
The composite material Na3+xV2(PO4-yFy)3 combines elements with complementary properties to achieve high energy density. Vanadium provides the redox couples for energy storage, phosphorus ensures structural stability, and fluorine doping enhances both structural integrity and electrical conductivity, collectively improving energy density
3Quantity of substance
If the electrode material uses higher sodium content to increase capacity, then the specific capacity increases, but the structural stability decreases leading to electrode disintegration
Solution Approach 1:
The patent precisely controls the sodium content parameter (x1 between 3.01-3.99) to maximize capacity while preventing structural collapse. The lower bound (3.01) ensures sufficient sodium for high capacity, while the upper bound (3.99) prevents excessive expansion that would cause disintegration. This parameter optimization balances capacity and stability
Solution Approach 2:
The multi-element composite structure Na3+xV2(PO4-yFy)3 provides synergistic effects where vanadium and phosphorus form a stable framework that accommodates variable sodium content. The fluorine doping further reinforces this framework, enabling the structure to maintain stability even at high sodium concentrations, thus allowing high capacity without disintegration
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 proposed electrode material improves the cyclic life and electric properties of sodium-ion batteries, maintaining structural integrity and increasing specific capacity and conductivity, thus overcoming the limitations of existing sodium-ion battery technologies.
Implementation Method 1
when a sodium-ion battery is charged, volume of the sodium ion drastically changes (i.e., expansion and contraction)
Implementation Method 2
The aggregated powder containing the oxide comprising sodium, vanadium, and phosphorus is dispersed to obtain a solution comprising a dispersed powder containing the oxide including sodium, vanadium, and phosphorus
Data Source
AI summary
An electrode material of a sodium-ion battery, a method of manufacturing the same, and an electrode of the sodium-ion battery are provided. The electrode material of the sodium-ion battery includes an oxide comprising sodium, vanadium, and phosphorus represented by formula 2 below:Na3+x2−yV2(PO4−yFy)3, wherein 0.01≤x2≤0.99 and 0.01≤y≤0.3. [formula 2]