Lithium Battery Electrolyte for Stable SEI and High-Temperature Storage

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Solution Overview

Problem

Lithium secondary batteries face performance degradation due to transition metal elution and anode expansion in high-temperature environments, leading to reduced stability and reliability.

Innovation Solution

An electrolyte formulation comprising a specific compound represented by Chemical Formula 1 and auxiliary additives forms a stable solid electrolyte interphase (SEI) on the anode surface, enhancing high-temperature storage properties and preventing metal elution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If silicon-based active material is used in the anode to achieve high capacity, then battery capacity is improved, but volume expansion occurs during repeated charging and discharging leading to increased battery thickness

Engineering Contradiction:

Improvebattery capacityVSAvoidbattery thickness

Core Design Contradiction:

Quantity of substanceVSVolume of moving object

Solution Approach 1:

The patent applies preliminary action by forming a protective coating layer on the silicon-based anode active material before it undergoes volume expansion during charging-discharging cycles. This pre-formed protective layer prevents direct contact between the electrolyte and silicon surface, thereby preventing harmful side reactions while allowing the silicon to expand and contract without degrading the battery structure or increasing thickness

Inventive Principle:

Principle #10Preliminary action

2Power

If the battery is exposed to high-temperature environment during repeated charging and discharging, then operational voltage and energy density are maintained, but transition metal elutes from the cathode and migrates to the anode surface causing performance deterioration

Engineering Contradiction:

Improveoperational voltage and energy densityVSAvoidbattery performance stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent introduces an intermediary substance in the form of a protective coating layer that acts as a barrier between the cathode and anode. This intermediary layer prevents direct migration of transition metals from the cathode to the anode during high-temperature operation, while still allowing lithium ion transport, thereby maintaining battery performance stability without sacrificing power output

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of high-temperature exposure by using it to form a stable solid electrolyte interphase (SEI) layer on the anode surface. This SEI layer, initially formed under thermal stress, actually protects the battery by preventing further transition metal migration and stabilizing the electrode structure during subsequent high-temperature cycling

Inventive Principle:

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

3Ease of manufacture

If conventional electrolyte composition is used to maintain simple formulation, then manufacturing cost is reduced, but battery stability and reliability at high temperature are insufficient

Engineering Contradiction:

Improveelectrolyte formulation simplicityVSAvoidhigh-temperature storage properties

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of the electrolyte, specifically incorporating compounds with specific molecular structures (as defined in Chemical Formula 1 of the patent). These compositional parameter changes enable the formation of a stable SEI layer at high temperatures, improving reliability while maintaining a relatively simple manufacturing process

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 electrolyte improves battery stability by reducing thickness increase and maintaining capacity retention and recovery in high-temperature conditions.

Implementation Method 1

An electrolyte formulation including a specific compound represented by Chemical Formula 1, along with auxiliary additives like fluorine-containing cyclic carbonate-based compounds, is used to form a stable solid electrolyte interphase (SEI) on the anode

Methodology Applied

Scientific EffectSolid electrolyte interphase (SEI) formation:

Implementation Method 2

An anode including a silicon-based active material as the anode active material may provide a high-capacity lithium secondary battery, but a volume expansion may be caused during the repeated charging and discharging

Methodology Applied

Scientific EffectVolume expansion constraint:

Implementation Method 3

The lithium secondary battery may be exposed to a high-temperature environment during repeated charging and discharging and overcharging. In this case, the transition metal may be eluted from the cathode to migrate to a surface of the anode

Methodology Applied

Scientific EffectTransition metal migration prevention:

Data Source

PatentUS12609355B2Electrolyte for lithium secondary battery and lithium secondary battery including the same

Publication Date: 2026.04.21 SK ON CO LTD

AI summary

An electrolyte for a lithium secondary battery includes a lithium salt, an organic solvent, and a compound represented by Chemical Formula 1. The compound forms a solid electrolyte interphase on a surface of an anode. A lithium secondary battery including the electrolyte and having improved high-temperature storage properties can be provided.