Rechargeable Lithium Battery Electrolyte for High-Voltage SEI Stability

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Solution Overview

Problem

Rechargeable lithium batteries face challenges in achieving stability and longevity at high temperatures, particularly due to the decomposition of positive electrode materials and gas generation.

Innovation Solution

An electrolyte comprising a non-aqueous organic solvent, lithium salt, and an additive represented by Chemical Formula 1, which forms a stable solid electrolyte interface (SEI) film on the positive electrode to suppress material decomposition and enhance high-voltage stability and cycle-life characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used in rechargeable lithium batteries, then basic battery operation is achieved, but stability and lifetime characteristics deteriorate at high temperatures

Engineering Contradiction:

Improvestability and lifetime characteristicsVSAvoidhigh temperature performance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent modifies the chemical structure of the cyclic carbonate additive by introducing cyano groups at specific positions (Y1-Y4 in Chemical Formula 1) to change its electrochemical properties. This structural parameter change enables the additive to form more stable SEI films at high temperatures, resolving the contradiction between basic operation and high-temperature stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The electrolyte uses a composite approach by combining the novel cyclic carbonate additive (Chemical Formula 1) with existing electrolyte components (non-aqueous organic solvent and lithium salt). This composite electrolyte formulation leverages the synergistic effects of different components to achieve both basic battery operation and improved high-temperature stability

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If high voltage operation is achieved, then energy density is improved, but positive electrode material decomposition increases

Engineering Contradiction:

Improveenergy densityVSAvoidpositive electrode material decomposition

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The cyclic carbonate additive with cyano groups acts as an intermediary substance that forms a protective SEI film on the positive electrode surface. This intermediary layer prevents direct contact between the electrolyte and electrode material, thereby suppressing decomposition while allowing high voltage operation for improved energy density

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The introduction of cyano groups (—CN) at specific positions in the cyclic carbonate structure changes the electrochemical window and stability characteristics of the additive. This parameter change in the additive's molecular structure enables it to effectively protect the positive electrode during high voltage charging, allowing higher energy density operation

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If battery capacity is increased, then energy storage is improved, but gas generation and electrode degradation increase

Engineering Contradiction:

Improvebattery capacityVSAvoidgas generation and electrode degradation

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potential harm of high capacity operation (which typically causes gas generation and degradation) into a benefit by using the cyclic carbonate additive with cyano groups. This additive preferentially reacts to form stable protective films that prevent the harmful side reactions, thereby enabling high capacity operation without the usual penalties of gas generation and electrode degradation

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 electrolyte formulation reduces gas generation and electrode degradation, ensuring improved stability and extended lifespan of lithium batteries even at high voltages and temperatures.

Implementation Method 1

forms a stable solid electrolyte interface (SEI) film on the positive electrode to suppress material decomposition

Methodology Applied

Scientific EffectSolid electrolyte interface (SEI) film formation:

Implementation Method 2

the positive and negative electrodes (e.g., each) include an active material in which intercalation and deintercalation (e.g. of lithium ions) are possible

Methodology Applied

Scientific EffectIntercalation and deintercalation:

Implementation Method 3

the rechargeable lithium battery generates electrical energy caused by oxidation and reduction reactions if (e.g., when) lithium ions are intercalated and deintercalated

Methodology Applied

Scientific EffectOxidation and reduction reactions: Redox Reactions

Data Source

PatentUS20250309347A1Electrolyte for rechargeable lithium battery and rechargeable lithium battery including the same

Publication Date: 2025.10.02 SAMSUNG SDI CO LTD

AI summary

An electrolyte and a rechargeable lithium batteries including the same are provided. The electrolyte comprises a non-aqueous organic solvent, a lithium salt, and an additive represented by Chemical Formula 1.