Secondary Battery Electrolyte Composition for Stable High-Salt Liquid State

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Solution Overview

Problem

Current secondary battery electrolytic solutions face challenges in achieving superior battery characteristics, such as stable liquid state and efficient lithium salt dissolution, due to limitations in solvent composition and molar ratios of sulfonyl compounds.

Innovation Solution

An electrolytic solution comprising a lithium salt, a sulfonyl compound with a combination of cyclic and chain compounds, and a fluorinated ether compound, where the sulfonyl compound includes at least one cyclic compound represented by Formula (1) and one chain compound represented by Formula (2), and the molar ratio of sulfonyl compound to lithium salt is between 2 and 4, ensuring stable dissolution and liquid state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sulfonyl compound is used as a solvent for dissolving lithium salt, then the battery characteristics are improved, but the electrolyte may become solid and unusable

Engineering Contradiction:

Improvebattery characteristicsVSAvoidelectrolyte state

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by precisely controlling the molar ratio of sulfonyl compound to lithium salt within the range of 2 ≤ ratio < 5. This parameter optimization ensures that the electrolyte maintains a stable liquid state while achieving superior battery characteristics, directly resolving the contradiction between reliability improvement and composition stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite electrolyte system combining sulfonyl compound (cyclic and/or chain types) with lithium salt and fluorinated ether compound. This composite approach creates a synergistic effect where the specific molar ratio ensures the electrolyte remains liquid while delivering enhanced battery performance, resolving the contradiction between improved reliability and stable composition.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If the molar ratio of sulfonyl compound to lithium salt is increased to improve dissolution, then the electrolyte remains liquid, but the composition becomes unstable

Engineering Contradiction:

Improveelectrolyte liquid stateVSAvoidbattery characteristics

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies parameter changes by establishing an optimized molar ratio range of 2 ≤ ratio < 5 for sulfonyl compound to lithium salt. This precise parameter control achieves the optimal balance where the electrolyte maintains stable liquid state while delivering superior battery characteristics, resolving the contradiction between composition stability and reliability.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If lithium salt concentration is increased to enhance battery capacity, then the energy density improves, but the electrolyte may solidify

Engineering Contradiction:

Improvelithium salt concentrationVSAvoidelectrolyte state

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by optimizing both the lithium salt concentration (1.159 ≤ concentration < 3.592 mol/L) and the molar ratio of sulfonyl compound to lithium salt (2 ≤ ratio < 5). This dual parameter optimization enables high lithium salt concentration for enhanced capacity while maintaining stable liquid electrolyte state, resolving the contradiction between quantity of substance and composition stability.

Inventive Principle:

Principle #35Parameter changes

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 solution enables a stable liquid electrolyte state, improving battery characteristics by maintaining the electrolyte in a usable form and enhancing the battery's capacity and cyclability.

Implementation Method 1

a solvent for dissolving an electrolyte salt

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

an electrolyte salt... dissolving and efficient lithium salt dissolution

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS20250007000A1Electrolytic solution for secondary battery, and secondary battery

Publication Date: 2025.01.02 MURATA MFG CO LTD

AI summary

An electrolytic solution for a secondary battery includes a lithium salt, a sulfonyl compound, and a fluorinated ether compound. The sulfonyl compound includes two or more selected from cyclic compounds and chain compounds. The sulfonyl compound includes at least one of the cyclic compounds. Each of the cyclic compounds is represented by Formula (1). Each of the chain compounds is represented by Formula (2). The fluorinated ether compound is represented by Formula (3). A concentration of the lithium salt is higher than or equal to 1.159 mol/L and lower than or equal to 3.592 moles per liter. A ratio of a number of moles of the sulfonyl compound to a number of moles of the lithium salt is greater than or equal to 2 and less than or equal to 4.