Solid-state lithium metal battery based on in-situ polymerization

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Solution Overview

Problem

The existing solid-state polymer lithium metal batteries suffer from unstable interfaces between lithium metal and electrolyte, leading to severe lithium dendrite growth, low coulombic efficiency, and short cycle life due to the instability of the initial solid-state electrolyte interphase (SEI) layer and poor compatibility between electrodes and electrolyte.

Innovation Solution

A double interphase layer with self-healing function is constructed at the interface of in-situ polymerization solid-state electrolyte and lithium metal using the synergistic effect of double Lewis acids, where a first Lewis acid forms a protective A-SEI layer on lithium metal, and a second Lewis acid is added to the electrolyte precursor solution to create a LiF-rich interphase layer with high modulus, promoting lithium salt dissociation and self-healing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If in-situ solid-state polymer electrolyte is used, then energy density is improved, but interface stability between lithium metal and electrolyte deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidinterface stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-treating the lithium metal surface with a first Lewis acid solution before electrolyte formation to create an initial protective SEI layer (A-SEI). This preliminary protective layer prevents direct contact between lithium metal and the in-situ solid-state electrolyte, stabilizing the interface before the electrolyte is fully formed and active.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses Lewis acids as intermediary substances that mediate between lithium metal and the solid-state electrolyte. The first Lewis acid forms an initial interphase layer, while the second Lewis acid modifies the electrolyte composition to create a LiF-rich interphase layer, acting as intermediaries that improve interface compatibility without compromising the high energy density benefits of the in-situ electrolyte system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If initial SEI layer is formed without modification, then formation process is simplified, but SEI layer stability deteriorates

Engineering Contradiction:

Improveformation process complexityVSAvoidSEI layer stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of the SEI layer through controlled addition of Lewis acids. The first Lewis acid changes the initial SEI formation parameters to create a more stable A-SEI layer, while the second Lewis acid changes the electrolyte composition parameters to promote formation of a LiF-rich interphase layer with higher mechanical strength and better stability.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If lithium metal reacts continuously with electrolyte, then interface reactivity is maintained, but interface impedance increases

Engineering Contradiction:

Improveinterface reactivityVSAvoidinterface impedance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by using Lewis acids to pre-form protective interphase layers that counteract the harmful continuous reaction between lithium metal and electrolyte. The A-SEI layer formed by the first Lewis acid and the subsequent LiF-rich interphase layer created by the second Lewis acid act as protective barriers that prevent direct harmful reactions while maintaining necessary ionic conductivity.

Inventive Principle:

Principle #9Preliminary anti-action

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

This approach enhances the stability and compatibility of the electrolyte interface, resulting in a lithium metal battery with high energy density, high coulombic efficiency, and ultra-long cycling life.

Implementation Method 1

adding solution containing a first Lewis acid on a surface of the lithium metal, and a layer of solid-state electrolyte interphase (A-SEI) is formed in-situ as a first protective layer

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

adding a second Lewis acid into precursor solution of in-situ solid-state electrolyte to form a second protective layer on the surface of lithium metal

Methodology Applied

Scientific EffectLewis acid-base interaction: Chemical Bonding

Implementation Method 3

in-situ solid-state electrolyte has better interface compatibility with electrodes, and its simpler preparation process

Methodology Applied

Scientific EffectPolymerization: Chemical Bonding

Data Source

PatentUS20240105925A1Solid-state lithium metal battery based on in-situ polymerization

Publication Date: 2024.03.28 YANGTZE DELTA REGION INST OF UNIV OF ELECTRONIC SCI & TECH OF CHINA HUZHOU

AI summary

According to the application, a double interphase layer strategy with self-healing function is constructed at an interphase between an in-situ solid-state electrolyte and a lithium metal by the synergistic effect of double Lewis acids, a first protective layer inhibits a side reaction of the lithium metal and the in-situ solid-state electrolyte, and a second protective layer self-heals defects of the double interphase layer. The application solves the problem of unstable interface between electrode and electrolyte of in-situ solid-state lithium metal battery, and obtains lithium metal battery with high energy density, high coulombic efficiency and ultra-long cycling life.