Sulfone-Ether Electrolyte for High-Voltage Battery Stability
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face challenges with the use of carbonate-based solvents, which cause oxidation reactions and gas generation, and sultone or sulfone-based solvents have high viscosity, low solubility, and reactivity, leading to poor cycle performance and ion conductivity.
Innovation Solution
The use of a combination of sulfone-based compounds and partially fluorinated ethers as solvents, along with lithium salts, to create a nonaqueous electrolyte solution that suppresses positive electrode reactions and improves impregnation and interface resistance, while maintaining low viscosity and oxidation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbonate-based solvents are used in the electrolyte solution, then the battery can achieve higher voltage and capacity, but oxidation reactions occur at the positive electrode during charge leading to gas generation and deterioration of battery performance
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte solvent from conventional carbonate-based solvents to a specific mixture containing sultone (15-40 vol%) and sulfone-based compounds (5-80 vol%). This parameter change in solvent composition allows the battery to operate at high voltages (4.4-5.0 V) without causing oxidation reactions and gas generation, while maintaining high capacity.
2Reliability
If sultone or sulfone-based compounds are used as solvents, then oxidation resistance is improved, but viscosity increases and solubility to lithium salt decreases leading to poor ion conductivity
Solution Approach 1:
The patent creates a composite electrolyte solution by combining sultone (15-40 vol%) with sulfone-based compounds (5-80 vol%). This composite approach leverages the oxidation resistance of sultone while the sulfone-based compound component maintains appropriate viscosity and ion conductivity, achieving both high reliability and good ionic transport.
3Reliability
If sultone or sulfone-based compounds are used as solvents, then oxidation resistance is improved, but impregnation property to electrode deteriorates leading to poor output characteristics
Solution Approach 1:
The patent optimizes the volume ratio parameters of sultone (15-40 vol%) and sulfone-based compounds (5-80 vol%) to achieve the right balance between oxidation resistance and electrode impregnation. This parameter optimization ensures that the electrolyte solution has both high oxidation resistance and good wetting properties for the electrodes, resulting in excellent output characteristics.
4Force
If carbonate-based solvent is mixed with sultone or sulfone-based solvent to decrease viscosity, then ion conductivity is improved, but carbonate-based solvent is preferentially oxidized causing gas generation
Solution Approach 1:
The patent extracts the harmful carbonate-based solvent from the electrolyte mixture and replaces it with a specific combination of sultone (15-40 vol%) and sulfone-based compounds (5-80 vol%). This extraction eliminates the preferential oxidation problem and gas generation while maintaining low viscosity and high ion conductivity through the synergistic combination of sultone and sulfone 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
This solution enhances cycle performance and charge/discharge efficiency by maintaining high peak voltages and reducing gas generation, resulting in improved battery output characteristics and stability.
Implementation Method 1
a nonaqueous electrolyte solution secondary battery which performs charge and discharge through the movement of lithium ion between positive and negative electrodes
Implementation Method 2
a solution prepared by dissolving a lithium salt such as LiPF6 or LiBF4 in an organic solvent such as a cyclic carbonate or a linear carbonate is used as an electrolyte solution
Data Source
AI summary
A nonaqueous electrolyte solution secondary battery of the embodiment includes an exterior material, a nonaqueous electrolyte solution, a positive electrode, a negative electrode and a separator sandwiched between the positive electrode and the negative electrode. The nonaqueous electrolyte solution is charged in the exterior material. The nonaqueous electrolyte solution contains at least one of sulfone-based compounds represented by formula 1, a partially fluorinated ether represented by a molecular formula of formula 2, and at least one of lithium salts. The positive electrode is housed in the exterior material. The positive electrode contains a composite oxide represented by L1−xMn1.5−yNi0.5−zMy+zO4 as a positive electrode active material (wherein 0≤x≤1, 0≤(y+z)≤0.15, and M represents one, or two or more selected from Mg, Al, Ti, Fe, Co, Ni, Cu, Zn, Ga, Nb, Sn, Zr and Ta). The negative electrode is housed in the exterior material.