Composite Battery Electrolyte With Flame Retardant for Safer Li-Ion Cells

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Solution Overview

Problem

Existing lithium secondary batteries face safety issues such as leakage, ignition, and explosion due to sudden environmental changes, and there is a need for improved electrochemical stability and ionic conductivity in secondary battery electrolytes.

Innovation Solution

The electrolyte includes a lithium salt, a composite membrane composed of an organic polymer and an inorganic electrolyte, and a flame retardant compound with a phosphorus-containing functional group, which is distributed both within and around the composite membrane to enhance stability and 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 issues such as leakage, ignition, and explosion occur due to sudden 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 a flame retardant compound with specific molecular structure (containing phosphorus and nitrogen atoms) into the solid electrolyte membrane, thereby improving safety while maintaining ionic conductivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite solid electrolyte membrane by combining organic polymer materials with inorganic flame retardant compounds, achieving both high ionic conductivity and improved safety against leakage, ignition, and explosion

Inventive Principle:

Principle #40Composite materials

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 exhibits self-extinguishing properties, improving safety against ignition and mechanical properties, and enhances both room-temperature and high-temperature stability, thereby extending the cycle life of lithium secondary batteries.

Implementation Method 1

a flame retardant compound including a phosphorus-containing functional group

Methodology Applied

Scientific EffectFlame retardancy:

Implementation Method 2

a composite membrane including an organic polymer and an inorganic electrolyte

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP4679551A1Secondary battery electrolyte, manufacturing method therefor, and lithium secondary battery comprising same

Publication Date: 2026.01.14 SK ON CO LTD

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AI summary

An electrolyte for a lithium secondary battery according to embodiments of the present disclosure may include a composite membrane including a lithium salt, an organic polymer, and an inorganic electrolyte, and a flame retardant compound including a phosphorus-containing functional group. The weight ratio of the flame retardant compound to the composite membrane may be 0.004 to 0.3. Accordingly, the flame retardancy and electrical properties of the secondary battery may be improved.