Printable Lithium Interface Layer for Solid-State Anode Contact
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Solution Overview
Problem
Lithium-ion batteries face a significant capacity loss due to the formation of a passivation film on the anode during the first charge cycle, resulting in irreversible capacity loss and reduced energy density, with existing solutions having limitations in safety and manufacturability.
Innovation Solution
A solid-state battery with prelithiated components using a printable lithium composition, comprising lithium metal powder, a polymer binder, and a rheology modifier, applied as an interface layer or anode, to enhance energy density, safety, and manufacturability by optimizing the contact between the lithium anode and solid electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium metal powder is stabilized by passivating the metal powder surface with carbon dioxide, then the lithium metal powder can be used in air with low moisture levels for a limited period of time, but the lithium metal content decays because of the reaction of the lithium metal and air
Solution Approach 1:
The patent uses a composite coating structure consisting of multiple layers (fluoropolymer layer, phosphorus-containing layer, and carbon-containing layer) to protect lithium metal powder. This multi-layer composite approach provides superior protection compared to single-layer coatings, preventing lithium metal decay while maintaining stability in air with low moisture levels.
Solution Approach 2:
The patent creates an inert protective environment around lithium metal powder through multiple coating layers that prevent direct contact between lithium metal and reactive components in air (moisture, oxygen). The fluoropolymer layer provides initial inert barrier, while subsequent layers enhance this protection, effectively creating a controlled inert microenvironment for the lithium metal.
2Reliability
If a coating such as fluorine, wax, phosphorus or a polymer is applied to the lithium metal powder, then the lithium metal powder is protected, but the coating may interfere with the electrochemical performance of the battery
Solution Approach 1:
The patent applies different coating materials with specific properties at different layers to achieve localized functions. The fluoropolymer layer provides initial protection and hydrophobicity, the phosphorus-containing layer provides intermediate protection and controlled reactivity, and the carbon-containing layer provides final protection with excellent electrochemical compatibility. This local differentiation allows each layer to optimize its specific function while collectively maintaining high electrochemical performance.
Solution Approach 2:
The patent carefully controls the thickness, composition, and physical-chemical parameters of each coating layer to balance protection and electrochemical performance. By adjusting parameters such as layer thickness (nanometer to micrometer scale), material composition ratios, and cross-linking density, the coating provides sufficient protection while maintaining adequate lithium ion transport and electrical conductivity for high electrochemical performance.
3Quantity of substance
If stabilized lithium metal powder is used to pre-lithiate the anode, then the capacity loss is compensated, but the solution has limitations in safety and manufacturability
Solution Approach 1:
The patent applies coating layers to lithium metal powder before it is incorporated into the battery anode structure. This preliminary protection is established during manufacturing, ensuring that the lithium metal powder is already protected against degradation before it undergoes electrochemical cycling. The pre-applied coatings maintain lithium capacity while enabling safer and more manufacturable battery production processes.
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 solution improves battery performance by maintaining higher energy density and safety while reducing irreversible capacity loss, with enhanced durability and manufacturability through the use of a printable lithium composition that forms a stable interface layer.
Implementation Method 1
The lithium moving from the cathode to the anode reacts with an electrolyte material at the surface of the graphite anode, causing the formation of a passivation film on the anode. The passivation film formed on the graphite anode is a solid electrolyte interface (SEI).
Implementation Method 2
When the secondary battery is being charged, or recharged, the lithium ions are transferred from the cathode to the anode through the electrolyte.
Implementation Method 3
During the discharge process, electrons are collected from the anode and pass to the cathode through an external circuit.
Data Source
AI summary
A battery having a cathode and a composite anode is provided. In one embodiment, the composite anode may include a lithium metal anode, a solid electrolyte and at least one interface layer. The interface layer improves the uniformity of the surface of the solid electrolyte thereby optimizing contact between the surface of the lithium metal anode and the surface of the solid electrolyte for better battery performance. The anode and/or the interface may be formed of a printable lithium composition including lithium metal powder, a polymer binder compatible with the lithium metal powder, a rheology modifier compatible with the lithium metal powder, and a solvent compatible with the lithium metal powder and with the polymer binder. The cathode may be a composite cathode. In another embodiment, the printable lithium composition may be in the form of a foil or film.