Electrolyte for rechargeable lithium battery, electrolyte additive and rechargeable lithium battery including the same

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Solution Overview

Problem

Rechargeable lithium batteries face challenges in achieving high-temperature stability, leading to issues such as gas generation and transition metal dissolution, which degrade performance and reduce battery life.

Innovation Solution

An electrolyte comprising a non-aqueous organic solvent, lithium salt, and an additive represented by Chemical Formula 1, which includes a sulfone group and azide group, is used to form a stable solid electrolyte interface (SEI) and cathode electrolyte interface (CEI), reducing side reactions and enhancing ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used in rechargeable lithium batteries, then basic battery operation is achieved, but high-temperature stability deteriorates leading to gas generation and transition metal dissolution

Engineering Contradiction:

Improvehigh-temperature stabilityVSAvoidgas generation and transition metal dissolution

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a fluorinated cyclic carbonate additive as an intermediary substance that mediates between the electrolyte and electrode surfaces. This additive preferentially decomposes to form protective interface layers (SEI and CEI) that act as barriers, preventing direct contact and harmful reactions between the electrolyte and electrodes at high temperatures, thereby eliminating gas generation and transition metal dissolution

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the electrolyte by incorporating fluorinated cyclic carbonate compounds with specific molecular structures (where R1-R6 represent various hydrocarbon groups). This parameter change in the additive's chemical structure enables formation of more stable protective layers compared to conventional non-fluorinated additives, directly improving high-temperature stability

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If high capacity electrodes are used to increase energy density, then battery capacity is improved, but interface stability deteriorates causing performance degradation

Engineering Contradiction:

Improvebattery capacityVSAvoidinterface stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by having the fluorinated cyclic carbonate additive decompose first during initial charging cycles to form stable protective interface layers (SEI on negative electrode and CEI on positive electrode) before the electrodes undergo normal operation. This pre-formed protective layer prevents subsequent interface degradation even when high capacity electrodes are used, maintaining long-term interface stability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protective interface layer formed by the fluorinated additive acts as an intermediary barrier between the high capacity electrodes and the bulk electrolyte. This intermediary layer allows lithium ion transport while preventing harmful chemical reactions, enabling high capacity electrodes to operate stably without performance degradation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If conventional additives are used, then basic electrolyte function is maintained, but ion conductivity and charge rate are limited

Engineering Contradiction:

Improvecharge rateVSAvoidion conductivity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the additive by using fluorinated cyclic carbonates instead of conventional non-fluorinated additives. This parameter change in the additive's molecular structure (incorporation of fluorine atoms) creates protective layers with optimized properties that maintain high ion conductivity while enabling faster charge rates, resolving the trade-off between conductivity and charging speed

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 high-temperature stability, maintaining capacity retention and reducing resistance, while providing rapid charge characteristics and extended battery life by protecting the SEI and CEI from decomposition.

Implementation Method 1

form a stable solid electrolyte interface (SEI) and cathode electrolyte interface (CEI)

Methodology Applied

Scientific EffectSolid electrolyte interface (SEI) formation:

Implementation Method 2

form a stable solid electrolyte interface (SEI) and cathode electrolyte interface (CEI)

Methodology Applied

Scientific EffectCathode electrolyte interface (CEI) formation:

Implementation Method 3

enhancing ion conductivity

Methodology Applied

Scientific EffectIon conductivity: Conduction (electrical)

Data Source

PatentUS20250329785A1Electrolyte for rechargeable lithium battery, electrolyte additive and rechargeable lithium battery including the same

Publication Date: 2025.10.23 SAMSUNG SDI CO LTD

AI summary

An electrolyte, an electrolyte additive, and a rechargeable lithium battery are disclosed. The electrolyte includes a non-aqueous organic solvent, a lithium salt, and an additive represented by Chemical Formula 1. A detailed description of the Chemical Formula 1 of the additive is disclosed.