LiNO3-Embedded Lithium Foil Anode for Dendrite-Stable Cycling

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Solution Overview

Problem

Lithium secondary batteries with Li-metal negative electrodes face issues of low coulombic efficiency, short lifetime, and safety concerns due to lithium dendrite growth and rapid decomposition of lithium nitrate in the electrolyte, leading to rapid degradation and potential safety hazards like fire and explosion.

Innovation Solution

A lithium secondary battery design featuring a lithium substrate with a lithium compound, such as LiNO3, uniformly incorporated on its surface and inside, which slows down the decomposition of lithium nitrate during charging and discharging, thereby improving the battery's lifetime characteristics and safety by preventing rapid lithium nitrate depletion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lithium nitrate is added to the electrolyte to suppress lithium dendrite growth, then battery safety is improved, but lithium nitrate rapidly decomposes during charging/discharging leading to shortened battery lifetime

Engineering Contradiction:

Improvebattery safetyVSAvoidbattery lifetime

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

Lithium nitrate is incorporated into the lithium substrate before battery operation begins. This preliminary incorporation ensures that lithium nitrate is already present at the electrode surface where it is needed to suppress dendrite growth, rather than relying on it to be present in the electrolyte and survive prolonged decomposition during cycling

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The lithium substrate acts as an intermediary carrier that delivers lithium nitrate directly to the electrode surface. By incorporating lithium nitrate into the lithium substrate, the system uses the substrate as a mediator to supply the protective lithium nitrate layer at the precise location where it is needed, bypassing the problem of lithium nitrate decomposition in the bulk electrolyte

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If lithium nitrate is incorporated only on the surface of the lithium substrate, then initial protective effect is achieved, but lithium nitrate depletes rapidly during operation reducing battery lifetime

Engineering Contradiction:

Improveinitial protective effectVSAvoidbattery lifetime

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

Lithium nitrate is nested within the lithium substrate structure, with lithium nitrate particles distributed throughout the bulk material. This nested configuration allows lithium nitrate to be progressively released or transported to the surface during battery operation, providing sustained protection rather than rapid depletion

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The uniform incorporation of lithium nitrate throughout the lithium substrate enables continuous supply of lithium nitrate to the electrode surface during charging and discharging cycles. As lithium ions move in and out of the substrate, lithium nitrate is continuously transported to the surface, maintaining the protective effect throughout battery operation rather than allowing rapid depletion

Inventive Principle:

Principle #20Continuity of useful action

3Duration of action of moving object

If lithium nitrate is uniformly incorporated in the inside and surface of the lithium substrate, then battery lifetime is extended by preventing rapid depletion, but manufacturing complexity increases

Engineering Contradiction:

Improvebattery lifetimeVSAvoidmanufacturing complexity

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The incorporation of lithium nitrate into the lithium substrate merges two separate steps (substrate preparation and lithium nitrate coating) into a single integrated process. By combining the lithium and lithium nitrate in one material component, the manufacturing process is simplified compared to applying separate surface coatings, even though uniform distribution throughout the substrate is achieved

Inventive Principle:

Principle #5Merging (Combining)

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 uniform distribution of lithium compounds like LiNO3 on the lithium substrate enhances the battery's discharging capacity and extends its lifetime by maintaining lithium nitrate levels, reducing overvoltage, and minimizing safety risks associated with lithium dendrite growth.

Implementation Method 1

the lithium nitrate is rapidly decomposed on the surface of the Li-metal negative electrode during the charging/discharging process of the battery to form a solid electrolyte interphase (SEI)

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS20240072310A1Negative electrode for lithium secondary battery and lithium secondary battery comprising same

Publication Date: 2024.02.29 LG ENERGY SOLUTION LTD

AI summary

The present disclosure relates to a negative electrode for a lithium secondary battery and a lithium secondary battery including the same, and more particularly, to a negative electrode for a lithium secondary battery and a lithium secondary battery including the same, which can improve the lifetime characteristics of the lithium secondary battery, wherein a lithium foil contained in the negative electrode includes LiNO3, and the LiNO3 is uniformly comprised in an inside and on a surface of the lithium foil.