Lithium Metal Anode Dimpled Surface for Dendrite Control

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Solution Overview

Problem

Lithium-ion batteries face issues with metal dendrite formation, leading to low Coulombic efficiencies, poor cycle performance, and safety concerns due to the degradation of active materials, which results in unusable lithium and potential internal short circuits.

Innovation Solution

The development of lithium-metal electrodes with predetermined surface designs featuring a plurality of dimples, which are formed through methods involving current density application, chemical etching, or mechanical processes to control lithium nucleation and inhibit dendrite growth, with dimples occupying a significant surface area and having specific size and depth ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lithium-ion batteries use conventional electrode structures, then manufacturing is simpler, but metal dendrite formation occurs leading to low Coulombic efficiency and poor cycle performance

Engineering Contradiction:

ImproveCoulombic efficiency and cycle performanceVSAvoidelectrode surface structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrode surface is designed with localized dimple features distributed across the surface, creating regions of enhanced lithium ion accommodation. These dimples have specific size ranges (1-50 μm diameter, 0.5-10 μm depth) and occupy 10-80% of the surface area, providing local sites for preferential lithium nucleation while maintaining overall electrode functionality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The dimple structures are pre-formed on the electrode surface before battery assembly and operation. This preliminary structural preparation creates ready-made sites for lithium ion deposition, preventing random dendrite formation during initial charging cycles and establishing uniform lithium distribution patterns from the outset

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If lithium-metal electrodes are used to increase energy density, then power requirements are better met, but dendrite formation and internal short circuits increase safety risks

Engineering Contradiction:

Improveenergy densityVSAvoiddendrite formation and internal short circuit risk

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The electrode surface morphology is modified by introducing dimple features with controlled geometric parameters (diameter 1-50 μm, depth 0.5-10 μm, occupying 10-80% surface area). These parameter changes create preferential nucleation sites that guide lithium ion deposition, transforming the random dendrite growth pattern into controlled, uniform lithium metal deposition within the dimple regions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The high reactivity of lithium metal, which normally leads to unwanted dendrite formation and side reactions, is harnessed by providing controlled nucleation sites. The dimple structures concentrate lithium ion flux to specific locations, converting the harmful random deposition into beneficial uniform lithium metal plating that increases energy density without compromising safety

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the electrode surface is modified with dimples to control lithium nucleation, then dendrite formation is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvedendrite suppressionVSAvoiddimple size and distribution control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Rather than requiring precise control of individual dimple features, the invention specifies ranges for dimple parameters (diameter 1-50 μm, depth 0.5-10 μm, surface area occupancy 10-80%) that collectively provide effective dendrite suppression. This approach to parameter specification balances manufacturing feasibility with performance requirements

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 surface design of lithium-metal electrodes with dimples enhances lithium ion cycling performance by reducing dendrite formation, improving discharge capacity retention, and maintaining stability across multiple cycles, thereby addressing safety and efficiency concerns.

Implementation Method 1

predetermined surface designs for preferential lithium nucleation during cell operation

Methodology Applied

Scientific EffectNucleation: Nucleation

Implementation Method 2

The metal dendrites may form protrusions that potentially puncture the separator and cause, for example, an internal short circuit

Methodology Applied

Scientific EffectDendrite formation inhibition:

Data Source

PatentUS20230261173A1Lithium metal anodes for use in electrochemical cell and methods of making the same

Publication Date: 2023.08.17 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An electrode including an electrochemical layer defining a surface having a plurality of dimples formed thereon is provided. The dimples have an average lateral size greater than or equal to about 100 nm to less than or equal to about 100 μm, and an average depth greater than or equal to about 100 nm to less than or equal to about 50 μm. In certain variations, the dimples are formed in situ by applying a current to the electrochemical layer. In other variations, the dimples are formed by moving a roller having a plurality of shapes defined thereon along one or more surfaces of the electrochemical layer. In still other variations, the dimples are formed by contacting one or more surfaces of the electrochemical layer with a chemical etchant.