Carbon-Coated Lithium Metal Electrode for Stable Cycling

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Solution Overview

Problem

Lithium metal negative electrodes in batteries face issues with lithium dendrite growth and cycling performance due to volume swelling, limiting their application in high-energy output fields.

Innovation Solution

A lithium metal negative electrode plate with a carbon material coating layer and a lithium metal alloy is developed, where the lithium metal alloy undergoes a phase change during intercalation and deintercalation, suppressing dendrite growth by diffusing lithium ions into the carbon material coating layer rather than towards the separator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal negative electrodes are used to achieve high theoretical capacity, then energy density is improved, but lithium dendrite growth and volume swelling occur causing poor cycling performance

Engineering Contradiction:

Improvetheoretical capacityVSAvoidcycling performance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A carbon coating layer is introduced as an intermediary between the lithium metal and the electrolyte. This carbon layer mediates the interaction by providing a stable interface that prevents direct contact between lithium and electrolyte, thereby suppressing dendrite growth while maintaining high capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The negative electrode is designed as a composite structure combining lithium metal with a carbon coating layer. This composite material approach allows the system to benefit from both the high capacity of lithium metal and the stability of carbon, resolving the contradiction between capacity and cycling performance

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If lithium metal negative electrodes are used to achieve high theoretical capacity, then energy density is improved, but volume swelling occurs during charging and discharging

Engineering Contradiction:

Improvetheoretical capacityVSAvoidvolume swelling

Core Design Contradiction:

Quantity of substanceVSVolume of moving object

Solution Approach 1:

A thin carbon coating film is applied on the lithium metal surface. This flexible thin film accommodates volume changes during lithiation and delithiation cycles, preventing structural degradation and volume swelling while maintaining electrode integrity

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The composite structure of lithium metal core with carbon coating shell provides both high capacity and volume stability. The carbon shell acts as a protective framework that maintains structural integrity during volume expansion and contraction

Inventive Principle:

Principle #40Composite materials

3Power

If lithium metal negative electrodes are used to achieve high energy output, then power is improved, but safety performance deteriorates due to dendrite formation

Engineering Contradiction:

Improveenergy outputVSAvoidsafety performance

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The carbon coating layer serves as a safety intermediary that physically separates the reactive lithium metal from the electrolyte. This mediator prevents harmful dendrite formation and potential short circuits while allowing ionic transport, thus improving safety without compromising power output

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The carbon coating converts the potentially harmful direct contact between lithium and electrolyte into a beneficial controlled interface. The coating transforms what would be a safety hazard (dendrite formation) into a controlled electrochemical interface that enhances both safety and performance

Inventive Principle:

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

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 design enhances energy density and cycling stability by reducing lithiation overpotential and preventing dendrite formation, thereby improving battery safety and performance.

Implementation Method 1

the lithium metal alloy undergoes a phase change during intercalation and deintercalation

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

diffusing lithium ions into the carbon material coating layer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS20230282836A1Lithium metal negative electrode plate, electrochemical apparatus, and electronic device

Publication Date: 2023.09.07 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

A lithium metal negative electrode plate, an electrochemical apparatus, and an electronic device are provided. In some embodiments, the lithium metal negative electrode plate includes copper foil and a carbon material coating layer formed on at least part of a surface of the copper foil, where thickness of the carbon material coating layer is less than or equal to 10 μm, and the carbon material coating layer includes a carbon material and a polymer binder. The lithium metal negative electrode plate, the electrochemical apparatus, and the electronic device provided in this application can effectively suppress formation and growth of lithium dendrites, thereby significantly improving first-cycle charge-discharge coulombic efficiency, cycling stability performance, and safety performance of batteries.