Porous Nanoparticle Layers for Dendrite Control

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Solution Overview

Problem

Conventional electrochemical devices, such as batteries, face performance degradation due to lithium dendrite formation and loss of discharge capacity during cycling, particularly when using lithium or lithium alloy anodes, where single porous coatings on electrodes are insufficient in preventing these issues.

Innovation Solution

Incorporating a first porous layer between the anode and separator and a second porous layer between the cathode and separator, utilizing nanoparticles with branched or chain-like structures, such as fumed metal oxide or metallic particles, to create a tortuous pathway that limits dendrite propagation and maintains high porosity even under pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single porous coating is applied on the electrode, then the device structure is simple, but it is insufficient in preventing lithium dendrite formation and performance degradation

Engineering Contradiction:

Improvedendrite prevention capabilityVSAvoidcoating structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the protective coating into multiple separate layers (first porous layer on anode, second porous layer on cathode) rather than using a single coating. Each layer is positioned at different locations within the electrochemical device to collectively prevent dendrite formation and performance degradation, thereby resolving the contradiction between reliability improvement and structural complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The porous layers act as intermediary structures between the electrodes and the electrolyte, providing a physical barrier that prevents direct contact and dendrite propagation. These intermediate layers mediate the interaction between electrodes and electrolyte, improving reliability while maintaining a manageable structural complexity through their specific porous nanoparticle composition.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional electrodes are used, then the device manufacturing is simple, but lithium dendrite formation occurs leading to capacity loss during cycling

Engineering Contradiction:

Improvedischarge capacity retentionVSAvoidelectrode assembly complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The porous layers are applied to the electrodes before assembly into the final device, creating a pre-prepared protective structure that prevents dendrite formation during subsequent cycling. This preliminary action of coating the electrodes with porous nanoparticle layers ensures discharge capacity retention while maintaining ease of manufacture through straightforward coating and assembly processes.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If porous layers are added between electrodes and separator, then dendrite propagation is limited, but the device structure becomes more complex

Engineering Contradiction:

Improvedendrite propagation resistanceVSAvoidlayer configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs porous materials with specific porosity characteristics (greater than 60% closest packed porosity) in the form of nanoparticle layers. These porous structures provide effective dendrite propagation resistance through their tortuous pathways while maintaining relatively simple device structure by using uniform nanoparticle-based layers rather than complex multilayer configurations.

Inventive Principle:

Principle #31Porous materials

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 configuration significantly enhances the durability and cycle life of electrochemical devices by preventing lithium dendrite formation and maintaining discharge capacity over multiple cycles, outperforming single-layer configurations even with equivalent total thickness.

Implementation Method 1

utilizing nanoparticles with branched or chain-like structures, such as fumed metal oxide or metallic particles, to create a tortuous pathway that limits dendrite propagation

Methodology Applied

Scientific EffectTortuous pathway:

Implementation Method 2

at least some of the nanoparticles of the first plurality of nanoparticles are in the form of a branched or chain-like structure... the first layer and the second layer each have a porosity of greater than or equal to 60%

Methodology Applied

Scientific EffectPorosity maintenance under pressure: Porosity

Data Source

PatentUS11710828B2Electrochemical devices including porous layers

Publication Date: 2023.07.25 SION POWER CORP

AI summary

Electrochemical devices that include porous layers, and associated methods, are generally described. In certain cases, the electrochemical device includes a first layer (e.g., a porous coating containing nanoparticles) between an anode and a separator, and a second layer (e.g., another porous coating containing nanoparticles) between a cathode and the separator. The first layer and/or the second layer may have a relatively high porosity, even after the application of an applied pressure to the electrochemical device. The presence of the first layer and the second layer in the electrochemical device may mitigate the occurrence of certain problematic phenomena during cycling of the electrochemical device.