Lithium Metal Battery Nitride Interlayer Against Oxide Formation
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Solution Overview
Problem
Conventional secondary batteries with metallic lithium deposition type negative electrodes suffer from low Coulomb efficiency due to oxidation and formation of lithium oxide during repeated charging and discharging cycles, leading to decreased battery capacity and conductivity issues.
Innovation Solution
Incorporating a covalent nitride of an element that can be alloyed with lithium between the electrolyte layer and the negative electrode current collector, which reduces oxidation of metallic lithium and enhances its conductivity by promoting a conversion reaction that forms lithium nitride, thereby maintaining electrochemical reactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic lithium is repeatedly deposited and dissolved between the electrolyte layer and negative electrode current collector, then battery capacity is maintained, but Coulomb efficiency decreases due to oxidation and lithium oxide formation
Solution Approach 1:
A nitride layer of element M is introduced as an intermediary between the electrolyte layer and negative electrode current collector. This intermediate layer prevents direct contact and oxidation between metallic lithium and oxygen-containing species, while still allowing lithium ion transport. The nitride layer acts as a protective mediator that maintains Coulomb efficiency by preventing harmful lithium oxide formation during repeated deposition and dissolution cycles.
Solution Approach 2:
The nitride layer creates an inert chemical environment for the metallic lithium by providing a chemically stable barrier that resists oxidation. Element M forms a covalent nitride structure that is chemically inert toward lithium, preventing the formation of lithium oxide while allowing ionic conduction. This inert environment protects the reactive metallic lithium during cycling.
2Reliability
If a nitride layer is introduced between electrolyte layer and negative electrode current collector, then oxidation of metallic lithium is reduced, but device structure becomes more complex
Solution Approach 1:
The invention optimizes specific parameters of the nitride layer including thickness (1-100 nm), composition (element M that can be alloyed with Li), and bonding type (covalent nitride). By controlling these parameters, the layer provides effective protection against oxidation while maintaining thin-film complexity. The covalent bonding nature ensures chemical stability without requiring complex multi-layer structures.
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 use of a covalent nitride between the electrolyte layer and the negative electrode current collector significantly improves the Coulomb efficiency of metallic lithium deposition and dissolution reactions, reducing lithium oxide formation and maintaining battery capacity.
Implementation Method 1
the nitride is covalent... reduces oxidation of metallic lithium
Implementation Method 2
promoting a conversion reaction that forms lithium nitride, thereby maintaining electrochemical reactivity
Implementation Method 3
metallic lithium as a negative electrode active material that is deposited between the electrolyte layer and the negative electrode current collector by charging
Implementation Method 4
an ionically conductive amorphous metal nitride layer... the electrolyte layer may contain a sulfide solid electrolyte
Data Source
AI summary
A secondary battery includes a positive electrode, an electrolyte layer, a negative electrode current collector, and metallic lithium as a negative electrode active material that is deposited between the electrolyte layer and the negative electrode current collector by charging, wherein a nitride of an element M is present between the electrolyte layer and the negative electrode current collector, wherein the element M is an element that is able to be alloyed with Li, and wherein the nitride is covalent.