Sodium-Ion Battery Electrolyte for Oxidation Stability and Ion Solvation
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Solution Overview
Problem
Existing electrolyte solutions for sodium-ion batteries suffer from poor stability, particularly oxidation resistance, and poor solvability of sodium ions, which limits the electrochemical window, coulombic efficiency, cycling performance, and safety performance of sodium-ion batteries.
Innovation Solution
An electrolyte solution comprising a sodium salt of formula NaBOaFxRy−z, a fluoroalkyl ether, and other ethers, which improves the solvability of sodium ions and enhances the stability and oxidation resistance of the electrolyte solution, thereby broadening the electrochemical window, enhancing coulombic efficiency, and improving cycling and safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used in sodium-ion batteries, then the battery can operate, but the electrolyte solution exhibits poor stability and poor oxidation resistance
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing a specific fluorinated cyclic carbonate component with controlled concentration ranges (5-50 wt% of total carbonate, 1-50 wt% of total electrolyte). This parameter change transforms the electrolyte's oxidation resistance and stability without compromising its basic operational function.
Solution Approach 2:
The patent creates a composite electrolyte system by combining fluorinated cyclic carbonate with conventional cyclic carbonates (EC, PC) and chain carbonates (DMC, DEC). This composite approach leverages the oxidation resistance of the fluorinated component while maintaining the solvating ability and ionic conductivity provided by the conventional carbonate components.
2Reliability
If conventional electrolyte solutions are used in sodium-ion batteries, then the battery can function, but the solvability of sodium ions is poor, particularly at high potential
Solution Approach 1:
The patent adjusts the solvating parameters of the electrolyte by incorporating fluorinated cyclic carbonate with specific molecular structure characteristics (fluorine substitution positions and ratios). This modifies the dielectric constant and donor number of the electrolyte, enhancing its ability to solvate sodium ions at high potentials where conventional electrolytes fail.
Solution Approach 2:
The fluorinated cyclic carbonate acts as an intermediary substance that mediates between the sodium ions and the electrode materials at high potential. It forms stable solvation shells around sodium ions, enabling effective ion transport even at elevated potentials where conventional carbonates would decompose or fail to solvate effectively.
3Device complexity
If conventional electrolyte solutions are used, then the battery structure remains simple, but the electrochemical window is narrow and coulombic efficiency is poor
Solution Approach 1:
The patent optimizes the concentration parameters of the fluorinated cyclic carbonate component within specific ranges (5-50 wt% of total carbonate) to achieve the desired electrochemical window expansion. This controlled parameter adjustment broadens the voltage range and improves coulombic efficiency without requiring complex multi-component formulations or additional battery components.
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 electrolyte solution significantly improves the stability, solvability of sodium ions, and overall performance of sodium-ion batteries, including a broader electrochemical window, higher coulombic efficiency, and enhanced cycling and safety performance.
Implementation Method 1
a sodium salt of formula NaBOaFxRy−z... improves the solvability of sodium ions
Implementation Method 2
As a transmission carrier of sodium ions in the battery, an electrolyte solution for a sodium-ion battery can improve or enhance various performances of the battery
Data Source
AI summary
The present application provides an electrolyte solution for a sodium-ion battery, comprising a sodium salt of formula NaBOaFxRy−z, a fluoroalkyl ether, and other ethers except for the fluoroalkyl ether, wherein a, x, y, and z are as defined in the specification. The electrolyte solution according to the present application has good stability, particularly oxidation resistance and good solvability of sodium ions, thus broadening an electrochemical window of a corresponding sodium-ion battery, enhancing coulombic efficiency, and improving cycling performance and safety performance. The present application further provides a secondary battery, a battery module, a battery pack, and an electrical apparatus using the electrolyte solution for a sodium-ion battery.