Composite Current Collector Layer for Dendrite-Controlled Lithium Plating

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Solution Overview

Problem

Lithium metal batteries, particularly anode-free lithium metal batteries, face issues with uncontrollable dendrite growth on current collectors, leading to thermal instability and rapid failure due to low cycle efficiency.

Innovation Solution

A composite modified layer comprising lithiophilic nanoparticles and a polymer, such as Ag@PDA, is applied to the current collector, optionally with a carbon-containing layer and an artificial protective layer of Polyvinylidene fluoride-hexafluoropropylene copolymer with lithium bis(trifluoromethanesulfonyl)imide, to inhibit dendrite formation and enhance lithium ion conductivity and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional current collector is used in anode-free lithium metal battery, then the battery structure is simple, but uncontrollable dendrite growth occurs leading to thermal instability and rapid failure

Engineering Contradiction:

Improvebattery stabilityVSAvoidcurrent collector structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining lithiophilic nanoparticles (such as Ag, Au, Cu, or their alloys) with polymer matrices (such as PVDF, PAN, or PAA) to create a composite modified layer. This composite structure provides both mechanical support and controlled lithium ion deposition sites, preventing dendrite growth while maintaining structural integrity and thermal stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by creating a heterogeneous surface with lithiophilic nanoparticle distribution zones that locally attract and guide lithium ion deposition. These localized lithiophilic regions provide preferential nucleation sites for uniform lithium plating, preventing localized dendrite formation while maintaining overall current collector functionality.

Inventive Principle:

Principle #3Local quality

2Reliability

If lithiophilic nanoparticles are added to inhibit dendrite growth, then dendrite formation is reduced, but the manufacturing complexity increases

Engineering Contradiction:

Improvecycle efficiencyVSAvoidcurrent collector fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-synthesizing and pre-distributing lithiophilic nanoparticles within the polymer matrix before applying the composite layer to the current collector. This pre-prepared composite structure ensures uniform nanoparticle distribution and eliminates the need for complex in-situ nanoparticle deposition processes, simplifying manufacturing while maintaining high cycle efficiency.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a composite modified layer with lithiophilic nanoparticles and polymer is applied to the current collector, then lithium ion conductivity is improved, but the device complexity increases

Engineering Contradiction:

Improvelithium ion conductivityVSAvoidcurrent collector structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the polymer matrix composition (using lithiophilic polymers like PVDF, PAN, or PAA) and controlling nanoparticle size and distribution parameters. These parameter optimizations enhance lithium ion conductivity through the composite layer while maintaining a relatively simple two-component structure that avoids excessive complexity.

Inventive Principle:

Principle #35Parameter changes

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 composite modified layer effectively reduces dendrite growth, improves lithium ion conductivity, and enhances mechanical strength, resulting in higher cycle efficiency and capacity retention, making it suitable for both liquid and solid state electrolytes.

Implementation Method 1

the lithium ion will firstly form an alloy with the silver nano-particles to decrease the thermal unitability during the growth of lithium nuclei crystal

Methodology Applied

Scientific EffectAlloy formation: Solid Solution Strengthening

Implementation Method 2

The silver nano-particles are securely attached on the current collector by the polymer with its high mechanical adhesion properties

Methodology Applied

Scientific EffectMechanical adhesion: Adhesive

Implementation Method 3

The composite modified layer provided by the present invention has high lithium ion conductivity

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS12119496B2Composite modified layer and anode-free lithium metal battery thereof

Publication Date: 2024.10.15 NAT TAIWAN UNIV OF SCI & TECH

AI summary

Present invention is related to a composite modified layer attached on a current collector comprising a lithiophilic particle being covered or coated by a polymer layer. The composite modified layer further could be coated with an additional carbon layer or artificial protective film as several suitable embodiments presented in this invention. The lithiophilic particle, such as sliver nano-particle, will firstly form a lithium-silver alloys to reduce a thermodynamic instability during the growth of lithium nuclei. The sliver nano-particle is able to be attached securely on the current collector by the polymer with high adhesion ability. The fuel cell including the composite modified layer in the present invention has higher average Coulombic efficiency and higher capacity retention.