Phosphazene Electrolyte Monomer for Flame-Retardant Li Batteries

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Solution Overview

Problem

Commercially available lithium secondary batteries using liquid electrolytes face safety issues such as leakage, ignition, and explosion due to environmental changes, necessitating the development of flame retardant additives for solid electrolytes to enhance stability and safety.

Innovation Solution

A monomer for an electrolyte is developed, represented by Formula 1, which includes a phosphazene group that generates polymetaphosphate upon combustion, forming a protective layer and carbon film to block oxygen and heat, and a polymerizable group for self-extinguishing properties, improving flame retardancy and ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid electrolytes are used in lithium secondary batteries, then high ionic conductivity is achieved, but safety problems such as leakage, ignition, and explosion occur due to environmental changes

Engineering Contradiction:

ImprovesafetyVSAvoidleakage, ignition, and explosion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to solid by incorporating phosphazene groups that generate polymetaphosphate upon combustion. This parameter change eliminates the harmful effects of liquid electrolytes (leakage, ignition, explosion) while maintaining ionic conductivity through the solid electrolyte structure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful combustion process into a beneficial protective mechanism. When combustion occurs, the phosphazene group generates polymetaphosphate that forms a protective layer and carbon film, blocking oxygen and heat to prevent further combustion. This transforms the potentially harmful combustion into a self-extinguishing safety feature

Inventive Principle:

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

2Reliability

If solid electrolytes are used to enhance stability, then safety against ignition and explosion is improved, but ionic conductivity may be reduced

Engineering Contradiction:

ImprovestabilityVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent creates a composite electrolyte structure incorporating phosphazene groups within the solid electrolyte matrix. This composite approach combines the stability of solid electrolytes with the flame retardant and ionic conductivity properties of phosphazene-containing compounds, achieving both safety and performance

Inventive Principle:

Principle #40Composite materials

3Reliability

If flame retardant additives are added to gel polymer electrolytes, then stability against ignition is improved, but the electrolyte composition becomes more complex

Engineering Contradiction:

Improveflame retardancyVSAvoidelectrolyte composition

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the flame retardant function with the electrolyte structure itself by incorporating phosphazene groups into the electrolyte composition. This integration eliminates the need for separate flame retardant additives, reducing composition complexity while maintaining flame retardancy

Inventive Principle:

Principle #5Merging (Combining)

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 monomer enhances the stability and electrochemical characteristics of lithium secondary batteries by improving flame retardancy, room-temperature and high-temperature safety, and ionic conductivity, thereby extending cycle life and electrical characteristics.

Implementation Method 1

a phosphazene group that generates polymetaphosphate upon combustion, forming a protective layer and carbon film to block oxygen and heat

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

a polymerizable group for self-extinguishing properties, improving flame retardancy and ionic conductivity

Methodology Applied

Scientific EffectSelf-extinguishing:

Data Source

PatentUS20250372730A1Monomer for electrolyte, electrolyte for secondary battery including the same, method of preparing the same and lithium secondary battery including the same

Publication Date: 2025.12.04 SK INNOVATION CO LTD

AI summary

A monomer for an electrolyte according to the embodiments of the present disclosure may include a compound represented by Formula 1. A lithium secondary battery according to the embodiments of the present disclosure includes a cathode, an anode, and an electrolyte, wherein the electrolyte may include a polymer of the compound represented by Formula 1.wherein X1, X2 and X3 are each independently a halogen element,R1, R2 and R3 are each independently hydrogen, a halogen element, a substituted or unsubstituted C1 to C6 alkyl group, or a polymerizable group, andat least one of R1, R2 or R3 is a polymerizable group.