Sodium-Ion Battery Electrolyte Balance to Prevent Sodium Plating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sodium-ion batteries face issues of low energy density, insufficient cycle life, and poor rate capability, with NaFSI as an electrolyte additive potentially corroding the current collector and deteriorating battery performance.
Innovation Solution
A sodium-ion battery design with a specific ratio (0.66 ≤ A/B ≤ 2.34) of slope area capacity ratio A to platform area capacity ratio B, using NaFSI as an electrolyte salt or additive within a controlled mass percentage (1% ≤ C ≤ 15%) to improve conductivity and inhibit sodium plating, ensuring stable film formation and preventing collector corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NaFSI is used as an electrolyte additive to improve conductivity and inhibit sodium plating, then the rate capability and cycling stability are improved, but it may corrode the current collector and deteriorate battery performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of NaFSI additive in the electrolyte (0.5-5 wt%) and optimizing the anode material parameters (particle size 3-10 μm, specific surface area 0.5-2.0 m²/g, capacity ratio A/B between 0.66-2.34). These parameter optimizations enable NaFSI to improve cycling stability while preventing current collector corrosion through controlled SEI film formation.
Solution Approach 2:
The patent uses the SEI film as an intermediary layer between the anode and electrolyte. By optimizing anode material parameters and controlling NaFSI concentration, a stable SEI film is formed that mediates the interaction between NaFSI and the current collector, allowing NaFSI to inhibit sodium plating and improve conductivity without causing corrosion.
2Quantity of substance
If the anode material has high capacity to improve energy density, then the battery performance is improved, but sodium plating may occur leading to cycling degradation
Solution Approach 1:
The patent applies parameter changes by optimizing the anode material's specific surface area (0.5-2.0 m²/g) and particle size (3-10 μm), which creates a balanced capacity distribution. This prevents localized high current density that causes sodium plating while maintaining high overall capacity. The capacity ratio A/B between 0.66-2.34 ensures uniform sodium ion insertion/extraction throughout cycles.
Solution Approach 2:
The optimized anode material structure acts as an intermediary that facilitates uniform sodium ion distribution. The controlled surface area and particle size create numerous uniform sites for sodium ion insertion, preventing concentration gradients that lead to plating. This intermediary structure maintains high capacity while ensuring cycling stability.
3Reliability
If the anode material particle size is reduced to increase specific surface area for better film forming, then the SEI film quality is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by defining an optimal particle size range (3-10 μm) and specific surface area range (0.5-2.0 m²/g) that balances SEI film quality with manufacturability. This parameter optimization ensures good film forming without requiring ultra-fine particle processing, thereby controlling manufacturing complexity and cost while achieving reliable battery performance.
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 design enhances the battery's rate capability and cycling stability by ensuring complete intercalation of sodium ions, reducing impedance, and maintaining electrolyte conductivity while preventing sodium plating and collector corrosion.
Implementation Method 1
the electrolyte comprises NaFSI (sodium bisfluorosulfonylimide) as an electrolyte salt or electrolyte additive... NaFSI can improve the conductivity, electrochemical and thermal stability of an electrolyte
Implementation Method 2
the negative electrode comprises an anode active material, the anode active material is a carbon material... ensures complete intercalation of sodium ions
Implementation Method 3
participate in the SEI film forming... improving the film forming quality of a solid electrolyte interface (SEI) film on an anode
Data Source
Figure 1
AI summary
A sodium-ion battery is provided, comprising a positive electrode, a negative electrode and an electrolyte. The electrolyte comprises NaFSI, and the mass percentage C of the usage amount of NaFSI relative to the electrolyte satisfies 1% ≤ C ≤ 15%. The disclosure ensures that a negative electrode has enough capacity to accommodate, such that Na+ deintercalated from a positive electrode can be completely intercalated into the negative electrode, and the sodium plating of Na+ on the negative electrode is prevented, thereby effectively inhibiting the occurrence of a sodium plating phenomenon; moreover, NaFSI is used in an electrolyte and the content range thereof is controlled, such that while the conductivity of the electrolyte is improved, the film-forming stability of positive and negative sides of a battery is good, and a current collector is not corroded, thereby effectively improving the rate capability and the cycling stability of the battery