Nanoporous Electrode Pillars for Homogeneous Lithium Deposition

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Solution Overview

Problem

Lithium-ion batteries face challenges in achieving homogeneous lithium deposition and maintaining electrode thickness stability during charging and discharging cycles, leading to degradation and mechanical stress due to lithium dendrite formation and migration.

Innovation Solution

A nano-porous negative electrode with conductor pillars on the current collector, partially covered with a lithiophilic material forming alloys with lithium, and a secondary lithium-conducting layer to facilitate uniform lithium deposition and reduce volume variations, utilizing materials like copper pillars, carbon nanotubes, and microporous carbons, with a porosity between 45% and 98% to maintain mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal is inserted within the porous matrix, then lithium deposition quantity is increased, but electrode thickness varies significantly during cycling

Engineering Contradiction:

Improvelithium deposition quantityVSAvoidelectrode thickness stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent utilizes a porous carbon matrix structure that can accommodate lithium deposition while maintaining structural integrity. The porous design allows lithium to be stored within the pores rather than causing external swelling, thus increasing lithium capacity while maintaining thickness stability.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent employs a composite structure combining porous carbon material with a protective layer containing lithium salt and carbon nanotubes. This composite design enables lithium storage within the carbon matrix while the protective layer prevents direct contact between lithium and liquid electrolyte, stabilizing the electrode structure during cycling.

Inventive Principle:

Principle #40Composite materials

2Reliability

If protective layer containing lithium salt is used, then lithium corrosion is prevented, but lithium dendrites form due to high nucleation energy

Engineering Contradiction:

Improvelithium corrosion preventionVSAvoidlithium dendrite formation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces carbon nanotubes as an intermediary layer between the protective layer and the lithium deposition surface. These nanotubes provide a controlled interface that reduces nucleation energy barriers, allowing lithium to deposit uniformly rather than forming dendrites, while the protective layer continues to prevent corrosion.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective layer is designed with local variations in composition and structure, including distributed carbon nanotubes and lithium salt, creating different functional zones. This local quality variation allows the layer to simultaneously prevent corrosion in some areas while providing low-nucleation-energy sites for uniform lithium deposition in others.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If lithium is stored in porous carbon structure, then homogeneous deposition is achieved, but mechanical strength decreases due to porosity

Engineering Contradiction:

Improvelithium deposition homogeneityVSAvoidelectrode mechanical strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent employs a porous carbon matrix with optimized pore size and distribution that can accommodate lithium deposition while maintaining structural integrity. The porous design allows lithium to be stored within the pores rather than causing external swelling, thus increasing lithium capacity while maintaining thickness stability.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

Inventive Principle:

Principle #40Composite 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

The solution enables a homogeneous lithium deposition within the nano-porous structure, significantly limiting electrode thickness variations and enhancing the mechanical strength and service life of lithium-ion batteries by preventing lithium migration and dendrite formation.

Implementation Method 1

a layer of a material consisting of at least one element forming alloys with lithium

Methodology Applied

Scientific EffectAlloy formation:

Implementation Method 2

Nanoporous electrode... a porosity between 45% and 98%

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS20230125633A1Nanoporous electrode

Publication Date: 2023.04.27 SAFT GRP SA

AI summary

The present application relates to an electrode comprising pillars of conductors covered with at least two layers for improving the deposition of lithium, and the electrochemical cells and batteries comprising same.