Sulfonate Ester Electrolytes for Stable SEI in Silicon Li-Ion Cells

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Solution Overview

Problem

Conventional electrolytes for lithium-ion batteries with silicon-based anodes and high-voltage cathodes face challenges such as unstable solid electrolyte interphase (SEI) layers, oxidative instability, and limited cycling life, leading to reduced battery performance and safety concerns.

Innovation Solution

The use of sulfonate ester compounds as electrolyte additives forms a stable, electronically insulating but ionically conducting SEI layer on silicon anodes and a protective cathode electrolyte interphase (CEI) layer on high-voltage cathodes, enhancing thermal stability and reducing flammability, thereby improving the electrochemical performance and safety of silicon anode-based Li-ion batteries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used with silicon-based anodes, then the battery can operate, but the SEI layer becomes unstable leading to reduced cycling life

Engineering Contradiction:

Improvecycling lifeVSAvoidSEI layer stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the electrolyte composition by introducing sulfonate ester compounds with specific molecular structures and functional groups. This chemical parameter change enables the formation of a stable SEI layer on silicon anodes, directly resolving the instability issue and improving cycling life

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sulfonate ester compounds act as intermediary substances that mediate between the silicon anode and the electrolyte. These compounds form a protective interface layer that prevents direct harmful interactions while maintaining ionic conductivity, thus stabilizing the SEI layer and enhancing reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional electrolytes are used with high-voltage cathodes, then the battery can operate, but oxidative instability occurs reducing performance

Engineering Contradiction:

Improveelectrochemical performanceVSAvoidoxidative stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces sulfonate ester compounds with specific oxidation resistance properties into the electrolyte formulation. This chemical composition change provides oxidative protection at high-voltage cathodes, preventing degradation reactions and maintaining electrochemical performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sulfonate ester compounds serve as intermediary protective agents between the high-voltage cathode and the electrolyte. They form a protective CEI layer that acts as a barrier against oxidative attacks, thereby enhancing both reliability and oxidative stability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If conventional electrolytes are used, then the battery operates, but thermal stability is reduced increasing flammability risks

Engineering Contradiction:

ImproveflammabilityVSAvoidthermal stability

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent modifies the electrolyte's thermal properties by incorporating sulfonate ester compounds with high thermal stability. This compositional change raises the decomposition temperature and reduces flammability, directly addressing the safety concerns associated with conventional electrolytes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of thermal degradation into a benefit by using sulfonate ester compounds that undergo controlled decomposition at high temperatures, forming protective char layers that prevent further thermal runaway and reduce flammability risks

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 sulfonate ester compounds stabilize the SEI and CEI layers, reducing capacity fade, enhancing cycling stability, and increasing thermal stability, which results in improved energy density, cycle life, and safety of silicon anode-based lithium-ion batteries.

Implementation Method 1

forms a stable, electronically insulating but ionically conducting SEI layer on silicon anodes

Methodology Applied

Scientific EffectSEI layer formation:

Implementation Method 2

forms a protective cathode electrolyte interphase (CEI) layer on high-voltage cathodes

Methodology Applied

Scientific EffectCEI layer formation:

Implementation Method 3

ionically conducting SEI layer

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS11901508B2Silicon-based energy storage devices with functionalized linear sulfonate ester derivative compound containing electrolyte additives

Publication Date: 2024.02.13 ENEVATE CORP

AI summary

Electrolytes and electrolyte additives for energy storage devices comprising a sulfonate ester compound are disclosed. The energy storage device comprises a first electrode and a second electrode, wherein at least one of the first electrode and the second electrode is a Si-based electrode, a separator between the first electrode and the second electrode, an electrolyte, and at least one electrolyte additive selected from a sulfonate ester compound.