Lithium Metal Anode with Aligned Porous Carbon for Uniform Deposition

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Solution Overview

Problem

Conventional lithium secondary batteries face reduced stability and lifetime due to lithium dendrite formation during charging/discharging, which existing protective layers and additives fail to adequately address.

Innovation Solution

A negative electrode design featuring a carbon-based thin film layer with porous carbon materials aligned in one horizontal direction on the lithium metal layer, preventing dendrite growth and enhancing mechanical strength and ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polymer protective layer or inorganic solid protective layer is introduced into the lithium metal layer, then lithium dendrite formation is partially suppressed, but the inhibitory effect is insufficient and the battery lifetime is still reduced

Engineering Contradiction:
Improvelithium dendrite suppressionVSAvoidbattery lifetime
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs a porous carbon coating layer with controlled pore size (10-100 nm) formed on the lithium metal layer. The porous structure allows uniform lithium ion insertion and extraction while the carbon material provides mechanical strength to suppress dendrite formation. The pore size is specifically controlled to be smaller than the critical dendrite diameter, physically preventing dendrite growth while maintaining ionic conductivity.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent uses a composite structure consisting of lithium metal layer combined with a carbon-based coating layer. The carbon material (such as amorphous carbon, graphite, or carbon nanotubes) forms a composite with the lithium metal, combining the high capacity of lithium metal with the dendrite-suppressing properties of carbon. This composite structure provides both ionic conductivity and mechanical reinforcement.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the carbon-based thin film layer with porous carbon materials aligned in one horizontal direction is formed on the lithium metal layer, then lithium dendrite formation is suppressed and lifetime characteristic is improved, but the device structure becomes more complex

Engineering Contradiction:
Improvebattery lifetimeVSAvoidelectrode structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent controls specific parameters of the carbon coating layer including pore size (10-100 nm), thickness (1-20 μm), and porosity (30-70%). By optimizing these parameters, the coating layer achieves effective dendrite suppression while maintaining good ionic conductivity and electron conductivity. The pore size is specifically controlled to be smaller than the critical dendrite diameter to physically block dendrite growth.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces directional alignment of porous carbon materials in the carbon-based thin film layer, with pores oriented in one horizontal direction forming an angle of 0 to 45° with the lithium metal layer. This local structural quality provides preferential pathways for lithium ion diffusion while maintaining dendrite suppression, creating anisotropic properties that enhance performance without excessive complexity.

Inventive Principle:
Principle #3Local quality

3Reliability

If salt concentration in electrolyte solution is increased, then lithium dendrite formation is partially inhibited, but the inhibitory effect remains insufficient

Engineering Contradiction:
Improvelithium dendrite suppressionVSAvoidelectrolyte composition
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent introduces a carbon-based coating layer as an intermediary between the lithium metal layer and the electrolyte solution. This intermediate layer modifies the interface properties, providing a controlled environment for lithium ion deposition. The carbon coating acts as a mediator that guides uniform lithium ion flux while preventing direct contact between the electrolyte and lithium metal, thereby suppressing dendrite formation more effectively than electrolyte modification alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 carbon-based thin film layer suppresses lithium dendrite formation, ensuring uniform reactivity and improving the battery's cycle lifetime characteristic by preventing internal short circuits and maintaining energy density.

Implementation Method 1

a plurality of porous carbon materials are aligned in one horizontal direction... suppressing the dendrites formation and permits the uniform deposition of lithium metal

Methodology Applied
Scientific EffectPhysical confinement effect:

Implementation Method 2

the carbon-based thin film layer... can suppress the formation of lithium dendrites and thus make the reactivity of the battery uniform

Methodology Applied
Scientific EffectStress distribution effect:

Implementation Method 3

enhancing mechanical strength and ionic conductivity... the pore size is space between the porous carbon materials

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP3731311B1Anode for lithium secondary battery and lithium secondary battery comprising same
Publication Date: 2024.02.14 LG ENERGY SOLUTION LTD
  • EP3731311B1 patent drawingFigure 1~2
  • EP3731311B1 patent drawingFigure 3~4
  • EP3731311B1 patent drawingFigure 5~6

AI summary

The present invention relates to a negative electrode for a lithium secondary battery comprising a lithium metal layer; and a carbon-based thin film layer in which a plurality of porous carbon materials are aligned in one horizontal direction, and a lithium secondary battery comprising the same.