Sulfonamide Silyl Additive for Lithium Battery Electrolyte

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Solution Overview

Problem

Lithium secondary batteries face issues with the decomposition of LiPF6, leading to gas generation, depletion of the electrolyte, and poor high-temperature performance due to reactions with the solvent, which affects their stability and safety.

Innovation Solution

Incorporating a compound represented by Formula 1, which includes a sulfonamide and silyl moiety, into the electrolyte to suppress solvent decomposition, capture PF5− ions, and form a stable SEI film, thereby reducing gas generation and improving thermal stability and cycle lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LiPF6 is used as a lithium salt in the electrolyte, then high ionic conductivity is achieved, but the electrolyte decomposes at high temperature generating gas and depleting the solvent

Engineering Contradiction:

Improvehigh-temperature stabilityVSAvoidgas generation and solvent depletion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a compound of formula (1) as an intermediary substance that mediates between LiPF6 and the electrolyte solvent. This compound captures PF5− ions generated from LiPF6 decomposition, preventing further solvent decomposition and gas generation while maintaining the beneficial ionic conductivity of LiPF6.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful PF5− ions generated from LiPF6 decomposition into a beneficial effect by having them captured and bound by the compound of formula (1). The harmful decomposition products are transformed into a stable complex that actually protects the electrolyte system from further degradation.

Inventive Principle:

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

2Reliability

If LiPF6 decomposes to produce LiF and PF5−, then ionic conductivity is maintained, but electrolyte depletion occurs leading to poor safety and performance

Engineering Contradiction:

Improvesafety and performanceVSAvoidelectrolyte depletion

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The compound of formula (1) acts as a mediator that intercepts PF5− ions before they can cause further electrolyte decomposition. By binding these ions, the compound prevents the chain reaction of decomposition that leads to electrolyte depletion, thereby protecting the overall electrolyte inventory.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs preliminary action by having the compound of formula (1) ready to capture PF5− ions as soon as they are generated from LiPF6 decomposition. This preemptive capture prevents the subsequent harmful effects of electrolyte depletion before they can occur.

Inventive Principle:

Principle #10Preliminary action

3Duration of action of moving object

If conventional electrolytes are used, then basic battery operation is achieved, but side reactions occur reducing lifetime characteristics

Engineering Contradiction:

Improvecycle lifetimeVSAvoidside reactions

Core Design Contradiction:

Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

The compound of formula (1) serves as a protective intermediary that reduces side reactions between LiPF6 and the electrolyte solvent. By capturing PF5− ions, it prevents multiple unwanted side reactions that would otherwise occur, thereby extending the cycle lifetime of the battery.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 additive enhances the high-temperature stability and cycle lifetime of lithium secondary batteries by reducing resistance and preventing swelling, while maintaining battery performance and conductivity.

Implementation Method 1

capture PF5− ions

Methodology Applied

Scientific EffectIon capture: Absorption (physical)

Implementation Method 2

form a stable SEI film

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Data Source

PatentUS11329318B2Electrolyte additive for lithium secondary battery and lithium secondary battery including the same

Publication Date: 2022.05.10 SAMSUNG SDI CO LTD

AI summary

Disclosed herein is an additive for a lithium secondary battery, the additive including a compound represented by Formula 1. An electrolyte for a lithium secondary battery includes: a lithium salt; a non-aqueous organic solvent; and the additive represented by Formula 1. A lithium secondary battery includes: a cathode; an anode; and the electrolyte including the additive represented by Formula 1.