Flexible Lithium Metal Electrode Structure for Dendrite Suppression

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Solution Overview

Problem

Lithium secondary batteries face issues with dendritic lithium growth, leading to short-circuits and poor stability, which affects their safety and lifespan.

Innovation Solution

A lithium electrode with a current collector having a surface irregularity structure, an electron-insulating protective layer comprising a non-porous layer and a polymer porous layer, and a lithium ion-isolating layer to inhibit dendritic lithium growth and enhance safety and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal is used as an active material for an electrode, then high capacity can be realized, but dendritic lithium growth occurs leading to short-circuits and poor stability

Engineering Contradiction:
ImprovecapacityVSAvoidstability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

A porous coating layer comprising a porous polymer matrix and inorganic particles is introduced as an intermediary between the lithium metal anode and the electrolyte. This coating layer acts as a mediator that allows lithium ion transport while preventing direct contact between lithium metal and electrolyte, thereby suppressing dendritic growth and improving battery stability without sacrificing capacity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The porous coating layer is constructed as a composite material system combining a porous polymer matrix with dispersed inorganic particles. The polymer matrix provides flexibility and ion transport pathways, while the inorganic particles enhance mechanical strength and further suppress dendritic lithium growth, creating a synergistic effect that simultaneously maintains capacity and improves stability

Inventive Principle:
Principle #40Composite materials

2Reliability

If a coating layer is applied to inhibit dendritic lithium growth, then safety is improved, but the complexity of the electrode structure increases

Engineering Contradiction:
ImprovesafetyVSAvoidelectrode structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A porous coating layer with controlled porosity is applied to the lithium metal anode surface. The porous structure allows efficient lithium ion transport while providing mechanical constraints that prevent dendritic growth. The porosity is optimized to balance ion conductivity and dendrite suppression, achieving safety improvement without excessive structural complexity

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The coating layer is applied specifically on the lithium metal anode surface where dendritic growth occurs, rather than uniformly across all electrodes. This localized application targets the problem area precisely, improving safety where needed while minimizing the overall structural complexity of the battery

Inventive Principle:
Principle #3Local quality

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 solution effectively prevents non-uniform dendritic lithium growth, improving the safety and rate characteristics of lithium secondary batteries while maintaining flexibility and preventing electrode structure collapse.

Implementation Method 1

an electron-insulating protective layer including a non-porous layer and a polymer porous layer, and thus inhibits non-uniform growth of dendritic lithium

Methodology Applied
Scientific EffectElectron insulation: Electrical Resistance

Implementation Method 2

a polymer porous layer comprising a porous polymer matrix and inorganic particles

Methodology Applied
Scientific EffectIon transport: Permeation

Implementation Method 3

prevents a collapse of the electrode structure caused by volumetric swelling of lithium metal

Methodology Applied
Scientific EffectVolumetric swelling: Thermal Expansion

Implementation Method 4

The lithium secondary battery generates electric energy by oxidation/reduction upon the intercalation/deintercalation of lithium ions into/from the cathode and the anode

Methodology Applied
Scientific EffectOxidation/reduction: Redox Reactions

Implementation Method 5

the intercalation/deintercalation of lithium ions into/from the cathode and the anode

Methodology Applied
Scientific EffectIntercalation/deintercalation: Absorption (physical)

Data Source

PatentEP3567667B1Flexible secondary battery
Publication Date: 2024.01.24 LG ENERGY SOLUTION LTD
  • EP3567667B1 patent drawingFigure 1a~1c
  • EP3567667B1 patent drawingFigure 1d~3a
  • EP3567667B1 patent drawingFigure 3b~4

AI summary

Disclosed is a lithium metal electrode including: a current collector having a surface irregularity structure provided with a top surface; a lithium metal layer disposed outside of the portion except the top surface of the surface irregularity structure in the current collector; an electron-insulating protective layer disposed outside of the lithium metal layer; and a lithium ion-isolating layer disposed on the top surface of the surface irregularity structure of the current collector, or on the top surface of the surface irregularity structure of the current collector, in the upper side of the lithium metal layer and in the upper side of the electron-insulating protective layer, wherein the electron-insulating layer includes a non-porous layer transporting lithium ions and having no pores, and a polymer porous layer disposed outside thereof. A lithium secondary battery and flexible secondary battery including the lithium metal electrode are also disclosed.