Iron-Air Accumulator Solid Electrolyte Mediator

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Solution Overview

Problem

The instability of nanostructured negative electrodes when combined with air electrodes in lithium-ion batteries, due to irreversible corrosion caused by contact with aqueous electrolytes, limits the mass energy density and capacity of electrochemical generators.

Innovation Solution

A solid lithium ion conducting electrolyte is deposited as a thin, impermeable layer on the nanostructured negative electrode to prevent contact with water and air, while maintaining the textile structure and preserving the advantages of the nanostructured conversion layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a nanostructured negative electrode is used to increase mass energy density, then the energy density is improved, but the electrode becomes unstable and undergoes irreversible corrosion due to contact with aqueous electrolyte

Engineering Contradiction:
Improvemass energy densityVSAvoidelectrode stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

A solid electrolyte layer is introduced as an intermediary between the nanostructured negative electrode and the aqueous electrolyte. This solid electrolyte conducts lithium ions while being impermeable to water, preventing direct contact between water and the sensitive nanostructured electrode material, thus eliminating corrosion while maintaining electrochemical functionality

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin solid electrolyte film is deposited directly on the surface of the nanostructured negative electrode. This thin film provides effective protection against water penetration while maintaining flexibility and preserving the high surface area characteristics of the nanostructured electrode, ensuring both stability and energy density

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If a solid electrolyte layer is deposited on the negative electrode to prevent water contact, then electrode stability is improved, but the device complexity increases

Engineering Contradiction:
Improveelectrode stabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The solid electrolyte layer is merged directly with the negative electrode structure by depositing it in situ on the electrode surface. This integration approach combines the protective function with the existing electrode architecture, avoiding the need for separate protective components and minimizing structural complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

A thin solid electrolyte film is used instead of thick protective layers or complex barrier structures. The thin film design provides effective protection while minimizing added volume, weight, and structural complexity, maintaining the compactness of the electrochemical generator

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

This solution enhances the stability and energy density of the negative electrode, allowing for increased mass capacity and preventing corrosion, thereby improving the performance of electrochemical generators.

Implementation Method 1

a continuous layer of a solid electrolyte, lithium ion conductor, impermeable to water and air, deposited directly on and completely covering the surface of the nanostructured active material of the electrode

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

a continuous layer of a solid electrolyte, lithium ion conductor, impermeable to water and air

Methodology Applied
Scientific EffectSelective permeability: Semipermeable Membrane

Implementation Method 3

a layer obtained by chemical or electrochemical transformation of the surface of the metallic material forming the current collector

Methodology Applied
Scientific EffectChemical transformation: Chemical Bonding

Implementation Method 4

a layer obtained by chemical or electrochemical transformation of the surface of the metallic material forming the current collector

Methodology Applied
Scientific EffectElectrochemical transformation: Electrochemiluminescence

Implementation Method 5

an air electrode, in contact with the aqueous electrolyte containing LiOH

Methodology Applied
Scientific EffectOxygen reduction reaction: Redox Reactions

Implementation Method 6

an oxygen evolution electrode, also in contact with the aqueous electrolyte containing LiOH

Methodology Applied
Scientific EffectOxygen evolution reaction: Redox Reactions

Data Source

PatentEP2274791B1Iron-air accumulator with lithium mediator
Publication Date: 2016.02.10 ELECTRICITE DE FRANCE
  • EP2274791B1 patent drawingFigure 1
  • EP2274791B1 patent drawingFigure 2

AI summary

The invention relates to a semi-accumulator that includes: (a) an electrode formed by an electron collector (3) comprising one or more transition metals from Groups 4 to 12 of the periodic table, and by an electrochemically active material (4) provided at the surface of the electron collector and in the form of a nanostructured conversion layer containing nanoparticles having a mean diameter of 1 to 1000 nm, said electrochemically active material containing at least one compound of the transition metal(s) provided in the electron collector; and (b) a continuous layer of a solid electrolyte (5) capable of conducting lithium ions, impervious to water and air and totally covering the surface of the nanostructured active material of the electrode (a). The invention also relates to an electrochemical generator comprising such a semi-accumulator as a negative electrode, preferably in the presence of an aqueous electrolyte containing LiOH.