Lithium-Rich Mixed Conductor Cathode for Lithium-Air Battery Stability
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Solution Overview
Problem
Lithium-air batteries face degradation due to decomposition of cathode materials caused by radicals generated during electrochemical reactions, leading to instability and reduced charge and discharge characteristics.
Innovation Solution
A chemically stable mixed conductor represented by Formula LixMO2-δ, where M is a Group 4 to 12 element, is developed, providing both electronic and ionic conductivity, which is incorporated into the cathode to prevent decomposition and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cathode materials (conducting agent and binder) are used in lithium-air batteries, then the battery can be manufactured with standard materials, but the cathode materials decompose due to radicals generated during electrochemical reactions, leading to deterioration and reduced stability
Solution Approach 1:
The patent removes conventional cathode materials (conducting agents and binders) that are susceptible to radical decomposition. Instead, it uses a lithium-rich layered oxide material that inherently provides both conducting and binder functions without being decomposed by radicals, thus extracting the problematic components while maintaining necessary functions.
Solution Approach 2:
The patent employs a composite lithium-rich layered oxide material with specific composition (Li1.2Mn0.54Co0.13Ni0.1Mg0.02O2) that combines multiple elements to achieve both structural stability against radicals and adequate electrochemical performance. This composite material simultaneously serves as cathode active material, conductor, and binder.
2Reliability
If a chemically stable mixed conductor is used to prevent decomposition, then cathode stability is improved, but the device complexity increases due to the need for specialized material synthesis
Solution Approach 1:
The patent modifies the chemical composition parameters of the cathode material by using a lithium-rich layered oxide with specific stoichiometry (Li1.2Mn0.54Co0.13Ni0.1Mg0.02O2) and controlled oxygen content (O2-δ). This parameter optimization achieves both chemical stability and adequate conductivity without requiring overly complex synthesis procedures.
Solution Approach 2:
The lithium-rich layered oxide material performs multiple functions simultaneously: it serves as the cathode active material, provides electronic conductivity, and acts as the binder holding the cathode structure together. This multi-functionality reduces the need for separate components and simplifies the overall cathode structure despite the specialized material requirements.
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 improves the stability and performance of lithium-air batteries by allowing efficient lithium ion and electron transfer, reducing internal resistance and maintaining electrochemical stability, thereby enhancing charge and discharge characteristics.
Implementation Method 1
a mixed conductor represented by Formula 1 and having electronic conductivity and ionic conductivity
Implementation Method 2
a mixed conductor represented by Formula 1 and having electronic conductivity and ionic conductivity
Implementation Method 3
first thermally treating the mixture to obtain a first thermal treatment product
Data Source
AI summary
A mixed conductor, a method of preparing the same, and a cathode, a lithium-air battery, and an electrochemical device each including the mixed conductor. The mixed conductor is represented by Formula 1 and having electronic conductivity and ionic conductivity:LixMO2-δ Formula 1wherein, in Formula 1, M is a Group 4 element, a Group 5 element, a Group 6 element, a Group 7 element, a Group 8 element, a Group 10 element, a Group 11 element, a Group 12 element, or a combination thereof, and 0<x<1 and 0≤δ≤1 are satisfied.