Mixed Conductor Electrode for Lithium-Air Battery Stability

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Solution Overview

Problem

Conventional electrochemical devices, such as batteries, face issues with internal resistance due to the decomposition of organic liquid electrolytes and carbonaceous conductive agents, which hinder ion and electron transfer, leading to instability and performance deterioration.

Innovation Solution

A mixed conductor represented by Formula A4±xTi5−yGzO12−δ is developed, which provides simultaneous ionic and electronic conductivity, stability, and improved ion and electron transfer through a spinel-type crystal structure and oxygen vacancies, allowing for the creation of a chemically stable electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If organic liquid electrolyte and carbonaceous conductive agent are used in electrode, then ionic and electronic conductivity are provided, but decomposition occurs leading to performance deterioration and increased internal resistance

Engineering Contradiction:

Improvechemical stabilityVSAvoidinternal resistance

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent uses a composite material consisting of Li4Ti5O12 (spinel structure) combined with conductive polymer materials to create an electrode that simultaneously provides ionic and electronic conductivity without decomposition. The composite structure allows Li-ion conduction through the spinel lattice while the conductive polymer phase provides electron transport pathways, eliminating the need for separate electrolyte and conductive agent components that suffer from decomposition issues.

Inventive Principle:

Principle #40Composite materials

2Power

If carbonaceous conductive agent is used for electron transfer, then electronic conductivity is improved, but ion transfer/diffusion is hindered

Engineering Contradiction:

Improveelectronic conductivityVSAvoidion transfer rate

Core Design Contradiction:

PowerVSSpeed

Solution Approach 1:

The electrode material is segmented into distinct functional phases: the Li4Ti5O12 spinel phase handles ionic transport through its three-dimensional lithium ion conduction pathways, while the conductive polymer phase handles electronic transport. This segmentation allows each phase to optimize its specific function without interfering with the other, preventing the carbonaceous agent from blocking ion diffusion paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the electrode material have specialized properties: the spinel phase provides ionic conductivity with its open crystal structure, while the conductive polymer regions provide electronic conductivity. This local differentiation of material properties enables simultaneous optimization of both ion and electron transfer without compromise.

Inventive Principle:

Principle #3Local quality

3Speed

If liquid electrolyte is used for ion transfer, then ionic conductivity is improved, but electron transfer is hindered

Engineering Contradiction:

Improveion transfer rateVSAvoidelectronic conductivity

Core Design Contradiction:

SpeedVSPower

Solution Approach 1:

The patent merges the functions of ionic conduction and electronic conduction into a single integrated electrode material. The Li4Ti5O12 conductive polymer composite simultaneously performs both ionic and electronic transport functions within one material phase, eliminating the need for separate liquid electrolyte components that would block electron transfer while enabling ion transfer.

Inventive Principle:

Principle #5Merging (Combining)

4Power

If conventional electrode materials are used, then electrochemical reactions occur, but decomposition by-products reduce device stability

Engineering Contradiction:

Improveelectrochemical reaction activityVSAvoiddevice stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the electrode material by using Li4Ti5O12 with its stable spinel crystal structure combined with conductive polymers. This parameter change in material composition provides high electrochemical stability and resistance to decomposition by-products while maintaining active electrochemical reaction capabilities, thereby improving device stability without sacrificing reaction activity.

Inventive Principle:

Principle #35Parameter changes

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 mixed conductor significantly reduces internal resistance in electrochemical devices by enhancing both ionic and electronic conductivity, improving the stability and performance of the devices, particularly in lithium-air batteries.

Implementation Method 1

a mixed conductor, i.e., a material having both electronic and ionic conductivity

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

a material having both electronic and ionic conductivity

Methodology Applied

Scientific EffectElectronic conduction: Conduction (electrical)

Implementation Method 3

transfers ions and electrons simultaneously through a spinel-type crystal structure and oxygen vacancies

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS11264181B2Mixed conductor, electrochemical device, and method of preparing mixed conductor

Publication Date: 2022.03.01 SAMSUNG ELECTRONICS CO LTD

AI summary

A mixed conductor represented by Formula 1:A4±xTi5−yGzO12−δ Formula 1wherein, in Formula 1, A is a monovalent cation, G is at least one of a monovalent cation, a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation, with the proviso that G is not Ti or Cr, wherein 0<x<2, 0.3<y<5, 0<z<5, and 0<δ≤3.