Protected Lithium Metal Powder for Dendrite-Resistant Electrodes

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Solution Overview

Problem

Lithium metal batteries face challenges with the formation of a solid electrolyte interphase (SEI) that leads to low first-cycle Coulombic efficiency and the growth of disordered lithium dendrites, which can pierce the separator membrane, posing safety concerns, and the thickness of commercial lithium metal is higher than required for efficient charge/discharge processes.

Innovation Solution

A method for preparing lithium metal powder involving ultrasonication with a metallic salt and solvent solution to form a mixed solution, which is then ultrasonically vibrated to create a protective layer, resulting in a lithium metal powder with a protective layer comprising sulfide, fluoride, or nitride, and applied to a substrate to reduce thickness and improve performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid electrolyte interphase (SEI) is formed on the lithium metal surface, then the lithium metal can be protected, but the first-cycle Coulombic efficiency decreases and disordered lithium dendrites form

Engineering Contradiction:

Improveprotection of lithium metalVSAvoidfirst-cycle Coulombic efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-forming an ordered protective layer on the lithium metal surface before battery operation. This protective layer is formed in advance through a controlled process involving lithium metal powder and a solution containing lithium salt and solvent, creating a structured interface that prevents subsequent dendrite formation while maintaining high Coulombic efficiency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs composite materials by creating a layered structure consisting of lithium metal powder combined with protective layer materials. The composite structure includes lithium metal core with an outer protective layer containing lithium salts and solvents, forming a composite material that combines the high capacity of lithium metal with the protective properties of the SEI layer

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If the thickness of lithium metal is reduced to improve energy density, then the energy density increases, but the charge/discharge efficiency may be compromised

Engineering Contradiction:

Improveenergy densityVSAvoidcharge/discharge efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent applies parameter changes by systematically optimizing the thickness of lithium metal powder and the composition of the protective layer. By adjusting parameters such as lithium metal particle size, protective layer thickness, and chemical composition, the patent achieves both reduced overall thickness for higher energy density and maintained charge/discharge efficiency through enhanced ionic conductivity

Inventive Principle:

Principle #35Parameter changes

3Productivity

If disordered lithium dendrites are allowed to form, then the lithium metal can be utilized, but the separator membrane can be pierced causing safety concerns

Engineering Contradiction:

Improvelithium metal utilizationVSAvoidsafety concerns

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by pre-forming an ordered protective layer that actively prevents the formation of disordered lithium dendrites. This protective layer creates a template-guided growth environment that directs lithium ion deposition in an ordered manner, counteracting the natural tendency toward dendrite formation before it can occur during battery operation

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful effect of SEI formation into a beneficial ordered protective layer. Instead of allowing random SEI formation that leads to dendrites, the patent uses a controlled process to create an ordered protective layer structure that maintains protection functionality while eliminating the harmful dendrite formation, effectively converting a harmful process into a beneficial one

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 lithium metal powder with a protective layer achieves improved first-cycle Coulombic efficiency, reduced thickness, and enhanced charge/discharge capabilities, increasing the energy density and safety of lithium batteries.

Implementation Method 1

ultrasonically vibrating the mixed solution to form a lithium metal powder

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentUS11965226B2Lithium metal powder, preparing method thereof, and electrode comprising the same

Publication Date: 2024.04.23 NAT YANG MING CHIAO TUNG UNIV

AI summary

The present invention relates to a lithium metal powder, a preparing method thereof, and an electrode including the same, wherein the method for preparing the lithium metal powder includes: providing a lithium metal material and a ultrasonication solution; mixing the lithium metal material and the ultrasonication solution to form a mixed solution; and ultrasonically vibrating the mixed solution to form a lithium metal powder, wherein the lithium metal powder is covered by a protective layer, and the aforementioned protective layer includes a protective layer material, wherein the protective layer material includes a sulfide, fluoride, or nitride, or a combination thereof.