Organic Electrolytic Solution for Lithium Battery Stability

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Solution Overview

Problem

High-capacity batteries with metal or alloy active materials face stability issues and decreased discharging capacity due to volume changes during charging and discharging, especially when stored at high temperatures, leading to increased electrolyte decomposition and resistance.

Innovation Solution

An organic electrolytic solution comprising a lithium salt, an organic solvent, and a novel compound that forms a film on the cathode, suppressing decomposition reactions and preventing metal ion dissolution, thereby enhancing cycle life and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high-capacity active materials (metals or alloys) are used to increase battery capacity, then battery capacity is improved, but volume changes during charging and discharging cause stability issues and decreased discharging capacity, especially at high temperatures

Engineering Contradiction:

Improvebattery capacityVSAvoidstability at high temperature

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a protective film composed of a specific compound (Formula 1) as an intermediary layer between the cathode active material and the electrolyte. This film acts as a mediator that prevents direct harmful interactions while allowing ionic transport, thereby resolving the contradiction between using high-capacity materials and maintaining stability at high temperatures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a thin protective film formed by the compound in Formula 1 on the cathode surface. This flexible film accommodates volume changes of the metal or alloy active materials during charging and discharging while maintaining structural integrity and preventing electrolyte decomposition, thus enabling high capacity with improved high-temperature stability.

Inventive Principle:

Principle #30Flexible shells and thin films

2Quantity of substance

If high charging voltage is used to obtain high-capacity batteries, then battery capacity is improved, but cathode active material stability is reduced and electrolyte decomposition is increased at high temperatures

Engineering Contradiction:

Improvebattery capacityVSAvoidelectrolyte decomposition

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The protective film formed by the compound in Formula 1 serves as an intermediary barrier between the cathode and electrolyte. It prevents direct contact and harmful electrochemical reactions at high charging voltages and temperatures, thereby suppressing electrolyte decomposition while maintaining high capacity performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful high voltage and temperature conditions into beneficial effects by using them to form a stable protective film on the cathode surface. This film then protects against further degradation, turning the harsh conditions that cause decomposition into the very conditions that create the protective barrier.

Inventive Principle:

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

3Quantity of substance

If metal or alloy active materials are used to increase capacity, then battery capacity is improved, but volume changes during charging and discharging increase resistance and reduce cycle life

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle life

Core Design Contradiction:

Quantity of substanceVSDuration of action of moving object

Solution Approach 1:

The patent uses a flexible protective film formed by the compound in Formula 1 that can accommodate the volume changes of metal or alloy active materials during charging and discharging cycles. This film maintains good contact throughout cycles, preventing resistance increase and extending cycle life while preserving high capacity.

Inventive Principle:

Principle #30Flexible shells and thin films

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 cycle life and high-temperature stability of lithium batteries by forming a protective film that prevents direct contact between the organic solvent and the cathode, reducing resistance and maintaining the solidity of the solid electrolyte interface.

Implementation Method 1

a compound represented by Formula 1 below... forms a film on the cathode

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 2

suppresses a decomposition reaction, by which a polar organic solvent is oxidized on the surface of a cathode

Methodology Applied

Scientific EffectChemical protection:

Implementation Method 3

suppresses the dissolution of metal ions from the cathode to the electrolytic solution

Methodology Applied

Scientific EffectIon dissolution prevention:

Data Source

PatentUS8372548B2Organic electrolytic solution and lithium battery employing the same

Publication Date: 2013.02.12 SAMSUNG SDI CO LTD

AI summary

An organic electrolytic solution including: a lithium salt; an organic solvent; and a compound represented by Formula 1 below, and a lithium battery including the organic electrolytic solution.In Formula 1: R1, R2, and R3 may be each independently a hydrogen atom, a C1 to C10 alkyl group, a C6 to C10 cycloalkyl group, a C6 to C10 aryl group, a C2 to C10 alkenyl group, or a C2 to C10 alkynyl group; X is C (R2) or nitrogen; and n is an integer ranging from 1 to 5.