Organic Electrolytic Solution for Lithium Battery Stability

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Solution Overview

Problem

High-voltage lithium batteries face instability and reduced discharge capacity due to decomposition of electrolyte solutions and metal ion elution, especially when stored at high temperatures, which affects their performance and lifespan.

Innovation Solution

An organic electrolytic solution comprising a lithium salt, an organic solvent, and a specific compound (represented by Formula 1) that forms a protective film on the cathode, inhibiting solvent decomposition and metal ion elution, and modifying the solid electrolyte interface to enhance the battery's cycle lifetime and prevent direct contact between the organic solvent and cathode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high voltage charging is used to achieve high capacity, then battery capacity is improved, but electrolyte decomposition and metal ion elution increase

Engineering Contradiction:

Improvebattery capacityVSAvoidelectrolyte stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A coating layer comprising a compound of Formula 1 is introduced as an intermediary between the cathode and electrolyte. This coating layer acts as a mediator that prevents direct contact between the electrolyte and cathode, thereby eliminating electrolyte decomposition and metal ion elution while allowing high voltage charging to proceed without harmful side reactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If high temperature storage is used to increase reaction rate, then battery output is improved, but discharge capacity decreases due to decomposition

Engineering Contradiction:

Improvebattery outputVSAvoiddischarge capacity

Core Design Contradiction:

PowerVSDuration of action of moving object

Solution Approach 1:

The coating layer of Formula 1 is applied in advance to the cathode surface to prevent harmful reactions before they can occur. This preliminary protective action blocks the pathways for electrolyte decomposition and metal ion elution that would otherwise be accelerated by high temperature storage, thereby preserving discharge capacity while allowing high power output.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If conventional electrolyte is used to maintain simplicity, then device complexity is reduced, but decomposition and metal ion elution occur

Engineering Contradiction:

Improveelectrolyte compositionVSAvoidelectrolyte decomposition

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

Instead of modifying the entire electrolyte system, the invention applies a localized coating layer of Formula 1 specifically on the cathode surface. This localized approach maintains the simplicity and bulk properties of the conventional electrolyte while introducing protective functionality only where it is needed - at the cathode-electrolyte interface - thereby preventing decomposition without complicating the overall system.

Inventive Principle:

Principle #3Local quality

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 improves the stability and cycle life of lithium batteries by preventing solvent decomposition and metal ion elution, allowing for efficient reversible charging and discharging over many cycles, even at high temperatures, thereby extending the battery's lifespan.

Implementation Method 1

modifying the solid electrolyte interface to enhance the battery's cycle lifetime and prevent direct contact between the organic solvent and cathode

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 2

inhibiting solvent decomposition and metal ion elution

Methodology Applied

Scientific EffectChemical inhibition:

Implementation Method 3

inhibiting solvent decomposition and metal ion elution

Methodology Applied

Scientific EffectIon retention:

Data Source

PatentUS8445142B2Organic electrolytic solution and lithium battery employing the same

Publication Date: 2013.05.21 SAMSUNG SDI CO LTD

AI summary

An organic electrolytic solution including a lithium salt, an organic solvent, and a compound represented by the formulaand a lithium battery employing the organic electrolytic solution. Groups Z1 and Z2 are each, independently, a cyano group, an isocyano group, a substituted or unsubstituted dicyanoethylphosphino group, or a substituted or unsubstituted dialkoxyphosphoryloxy group. Groups R1 through R4 are described fully in the Description. The organic electrolyte solution inhibits decomposition of an electrolytic solution and elution or precipitation of metal ions, and thus the lithium battery including the organic electrolytic solution has excellent cycle characteristics and lifetime characteristics.