Lithium Battery Negative Electrode with Metal Nanostructure

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Solution Overview

Problem

Lithium secondary batteries face challenges with discharge capacity and lifespan due to the porous structure of carbonaceous materials and the deterioration of lithium-alloyable metals like Sn during repeated charging and discharging.

Innovation Solution

A lithium battery design featuring a negative electrode with a metal/metalloid nanostructure, such as silicon-based nanowires, and an organic electrolytic solution containing a lithium sulfonimide-based compound to absorb volumetric changes and prevent side reactions, thereby enhancing discharge capacity and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If carbonaceous materials with porous structure are used as negative electrode, then volumetric change during charging and discharging is reduced, but battery capacity becomes small

Engineering Contradiction:

Improvevolumetric stabilityVSAvoidbattery capacity

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent combines carbonaceous materials (graphite, amorphous carbon) with lithium-alloyable metals (Si, Sn, Al) to create a composite negative electrode. This merging allows the carbon component to provide volumetric stability while the metal component contributes high capacity, resolving the contradiction between structural stability and capacity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The negative electrode uses composite materials consisting of carbonaceous materials and lithium-alloyable metals. The carbon matrix provides structural stability and accommodates volume changes, while the metal particles dispersed within provide high lithium alloying capacity, simultaneously achieving both volumetric stability and high battery capacity.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If lithium-alloyable metals (Si, Sn, Al) are used as negative active material, then electric capacity is higher than carbonaceous materials, but lifespan characteristics deteriorate due to particle aggregation and crushing

Engineering Contradiction:

Improveelectric capacityVSAvoidlifespan characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent creates a composite structure where lithium-alloyable metal particles are locally dispersed within a carbonaceous matrix. The carbon material provides a stable local environment that constrains metal particle movement and prevents aggregation, while the metal particles maintain their high capacity function. This local quality differentiation resolves the lifespan issue while preserving capacity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The carbonaceous material acts as a flexible shell or matrix that envelops and protects the lithium-alloyable metal particles. This carbon shell accommodates volume changes during charging-discharging cycles and prevents direct contact between metal particles, thereby preventing aggregation and crushing that would otherwise reduce lifespan.

Inventive Principle:

Principle #30Flexible shells and thin films

3Quantity of substance

If Sn particles are used as negative active material, then high electric capacity is achieved, but particles are repeatedly aggregated and crushed during charging and discharging

Engineering Contradiction:

Improveelectric capacityVSAvoidparticle stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The carbonaceous material forms a flexible shell or matrix that envelops the Sn particles. This carbon shell accommodates the volumetric expansion and contraction of Sn during lithium alloying and de-alloying, preventing particle crushing. The shell also physically separates Sn particles, preventing aggregation, thereby maintaining particle stability while preserving high electric capacity.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite material system where Sn particles are dispersed within a carbonaceous matrix. The carbon component provides mechanical stability and prevents Sn particle aggregation and crushing, while the Sn particles provide high electric capacity through lithium alloying. This composite structure resolves the contradiction between capacity and particle stability.

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 lithium battery exhibits improved discharge capacity and lifespan characteristics, as the nanostructure effectively manages volumetric changes and the lithium sulfonimide-based compound prevents deterioration, leading to better performance and longevity.

Implementation Method 1

the negative electrode has a metal/metalloid nanostructure... the nanostructure effectively manages volumetric changes

Methodology Applied

Scientific EffectVolumetric change absorption: Elasticity

Implementation Method 2

the organic electrolytic solution includes a lithium sulfonimide-based compound... the lithium sulfonimide-based compound prevents deterioration

Methodology Applied

Scientific EffectSide reaction prevention: Chemical Bonding

Data Source

PatentUS9882237B2Lithium battery

Publication Date: 2018.01.30 SAMSUNG SDI CO LTD

AI summary

Provided is a lithium battery including: a positive electrode, a negative electrode, and an organic electrolytic solution, wherein the negative electrode has a metal/metalloid nanostructure, and the organic electrolytic solution includes a lithium sulfonimide-based compound.