Solid Electrolyte Separator Coating Against Lithium Dendrite Penetration

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Solution Overview

Problem

Lithium batteries face issues with the growth of metallic lithium dendrites during charge-discharge cycling, leading to internal short circuits and reduced safety.

Innovation Solution

A separator is designed with a first isolation layer and a coating containing a solid electrolyte material, along with a second isolation layer, to prevent the growth of lithium dendrites and enhance battery safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separator is used to prevent lithium dendrite growth, then battery safety is improved, but the separator thickness increases reducing energy density

Engineering Contradiction:

Improvebattery safetyVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The separator is constructed as a composite structure combining an organic base film with inorganic coating layers (such as Al2O3, SiO2, TiO2) and solid electrolyte materials. This composite design provides enhanced dendrite resistance and mechanical strength while maintaining thin overall thickness, thus improving safety without significantly reducing energy density

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The separator employs a multi-layer nested structure where the inorganic coating is deposited on the organic base film, and solid electrolyte materials are integrated within or on the coating layers. This nested arrangement allows multiple functional layers to be compactly integrated, providing comprehensive protection against dendrites while minimizing the total thickness to preserve energy density

Inventive Principle:

Principle #7Nested doll (Nesting)

2Strength

If inorganic coating is applied to the separator, then mechanical strength and insulation ability are improved, but the weight of the separator increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidseparator weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The inorganic coating is applied selectively on specific surfaces or regions of the base film where mechanical strength and insulation are most needed, rather than uniformly throughout the entire separator structure. This localized application provides necessary strength enhancement while minimizing the total inorganic material content and associated weight increase

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The inorganic coating is designed with a porous structure that provides mechanical strength and insulation properties through the coating architecture rather than through material density. The porous structure reduces the amount of inorganic material required, thereby minimizing weight increase while maintaining the necessary mechanical properties

Inventive Principle:

Principle #31Porous materials

3Reliability

If solid electrolyte material coating is applied, then lithium-ion conductivity is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvelithium-ion conductivityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The solid electrolyte material coating process is merged with the existing inorganic coating deposition process, allowing both the inorganic coating and solid electrolyte materials to be applied in a single manufacturing step or closely integrated sequence. This integration reduces the number of separate manufacturing steps and simplifies the overall production process while maintaining high lithium-ion conductivity

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 proposed separator effectively reduces the growth of lithium dendrites, thereby improving the safety and performance of lithium batteries by preventing internal short circuits.

Implementation Method 1

the coating exhibits lithium-ion conductivity. In an embodiment, at 25° C., an ion conductivity of the coating ranges from 0.5 S/cm to 5 S/cm

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

The inorganic coating exhibits hardness to a degree, and can prevent lithium dendrites from penetrating the separator to some extent

Methodology Applied

Scientific EffectHardness: Meyer Hardness Test

Implementation Method 3

The inorganic coating can provide overall mechanical strength of the separator, improve the insulation ability of the separator, and improve the wettability of the separator to an electrolyte solution

Methodology Applied

Scientific EffectWetting: Wetting

Data Source

PatentUS20250202059A1Separator and preparation method thereof, coating slurry and preparation method thereof, electrode assembly, battery, and electrical device

Publication Date: 2025.06.19 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

This application relates to the technical field of separators, and in particular, to a separator and a preparation method thereof, a coating slurry and a preparation method thereof, an electrode assembly, a battery, and an electrical device. The separator includes a first isolation layer, a coating, and a second isolation layer. The coating is disposed on at least one surface of the first isolation layer. The coating includes a solid electrolyte material. The second isolation layer is disposed on a surface of the coating, the surface being away from the first isolation layer. The solid electrolyte material can react with metallic lithium to absorb lithium dendrites to prevent the lithium dendrites from penetrating the separator.