Protected Anode for Lithium Air Battery Using Composite Material
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Solution Overview
Problem
Lithium air batteries face instability and dendrite formation due to the use of metallic lithium, leading to reduced charge and discharge efficiencies and a high risk of explosion, as well as performance degradation from reactions with oxygen and electrolytes.
Innovation Solution
A protected anode is developed using lithium titanium oxide as the anode active material and a protective layer composed of a compound represented by Formula Li1+XMXA2−XSiYP3−YO12, where M can be aluminum, iron, indium, or chromium, and A can be germanium, tin, or zirconium, with a protective layer directly applied without an interlayer, enhancing stability and interface conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metallic lithium is used as negative active material to achieve high capacity, then battery capacity is improved, but stability and safety deteriorate due to dendrite formation and high reactivity
Solution Approach 1:
The patent uses lithium titanium oxide (Li4Ti5O12) as a composite anode material that combines the high capacity benefits of lithium-based materials with the stability of titanium oxide. This composite structure prevents dendrite formation while maintaining high lithium ion conductivity, resolving the contradiction between capacity and stability.
Solution Approach 2:
The patent introduces a protective layer as an intermediary between the anode and electrolyte. This layer acts as a barrier that prevents direct contact and harmful reactions, while still allowing lithium ion transport. The protective layer mediates the interaction between the high-capacity lithium material and the electrolyte, preventing dendrite formation and improving safety.
2Quantity of substance
If metallic lithium anode is used to achieve high capacity, then battery capacity is improved, but charge and discharge efficiency deteriorates due to dendrite deposition
Solution Approach 1:
Lithium titanium oxide provides a stable crystalline structure that facilitates rapid lithium ion insertion and extraction without forming dendrites. This composite material enables high charge and discharge rates while maintaining capacity, as the spinel structure allows efficient ion transport pathways.
Solution Approach 2:
The protective layer serves as an intermediary that ensures uniform lithium ion distribution during charging and discharging. By preventing localized dendrite growth, it maintains efficient charge transfer and prevents electrode disconnection, thereby preserving high charge and discharge efficiency.
3Reliability
If protective layer is added to improve stability, then safety is improved, but device complexity increases due to additional layers
Solution Approach 1:
The protective layer is applied selectively only where needed - on the surface of the anode material that contacts the electrolyte. This localized protection provides safety benefits without requiring complete structural redesign of the entire battery, thus limiting the increase in device complexity to only the necessary protective interface.
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 protected anode achieves long battery lifetime, high-rate characteristics, and improved conductivity, reducing dendrite formation risks and maintaining stability, while avoiding the need for an interlayer, thus enhancing charge and discharge performance.
Implementation Method 1
a protective layer which is formed on the surface of the anode and includes a compound represented by Formula 1 below: Li1+XMXA2−XSiYP3−YO12
Data Source
AI summary
A protected anode including an anode including a lithium titanium oxide; and a protective layer including a compound represented by Formula 1 below, a lithium air battery including the same, and an all-solid battery including the protected anode:Li1+XMXA2−XSiYP3−YO12 <Formula 1>wherein M may be at least one of aluminum (Al), iron (Fe), indium (In), scandium (Sc), or chromium (Cr),A may be at least one of germanium (Ge), tin (Sn), hafnium (Hf), and zirconium (Zr),0≦X≦1, and0≦Y≦1.