Lithium Active Material Composite Shell
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Solution Overview
Problem
Lithium metal in batteries is highly reactive, requiring stringent storage and operation conditions to prevent oxidation-reduction reactions, which increases costs and risks combustion, and existing solutions like lithium carbonate shells or low-polarity solvents pose environmental and health hazards.
Innovation Solution
A composite layer comprising a protection layer that alloys with lithium and a structural layer with high structural strength and conductivity, which isolates lithium from moisture and oxygen, allowing normal storage and operation conditions while maintaining electrical and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as active material to achieve high energy density, then power supply capability is improved, but chemical stability deteriorates causing oxidation reactions with oxygen and moisture
Solution Approach 1:
The patent applies composite materials by creating a core-shell structure where lithium metal core is coated with a protective shell material. This composite structure combines the high energy density of lithium metal with the chemical stability of the shell material, resolving the contradiction between energy density and chemical stability.
Solution Approach 2:
The protective shell material creates an inert environment around the lithium metal, preventing direct contact between lithium and reactive substances (oxygen and moisture) in the surroundings. This inert barrier maintains chemical stability while preserving the energy density benefits of lithium metal.
2Productivity
If lithium particle size is reduced to micrometer or nanometer scale to increase reaction surface area, then electrochemical performance is improved, but reactivity with oxygen and moisture increases severely
Solution Approach 1:
The patent employs a thin film protective shell that conforms to the reduced-scale lithium particles. This flexible shell provides comprehensive coverage over the high-surface-area particles, preventing harmful reactions while maintaining the electrochemical advantages of small particle size.
Solution Approach 2:
The core-shell composite structure is particularly effective for small particles, where the shell-to-core ratio provides adequate protection without significantly increasing overall particle size, thus maintaining high surface area while suppressing reactivity with oxygen and moisture.
3Reliability
If lithium metal is covered with lithium carbonate shell to prevent reactions, then storage and operation safety is improved, but environmental harm and health hazards increase due to required low-polarity solvents
Solution Approach 1:
The patent changes the chemical composition parameters of the protective shell, moving from lithium carbonate to alternative materials that enable the use of environmentally friendly, high-polarity solvents. This parameter change in shell material composition resolves the contradiction by eliminating the need for harmful low-polarity solvents while maintaining safety.
Solution Approach 2:
The protective shell acts as a sacrificial or consumable barrier that can be replaced or degraded without affecting the core lithium metal. This approach allows for safer, more environmentally compatible materials in the shell that may be less durable but eliminate harmful solvent requirements.
4Reliability
If stringent storage and operation conditions are maintained to prevent oxidation reactions, then chemical stability is improved, but process cost increases
Solution Approach 1:
The protective shell is applied in advance during the manufacturing process, creating a permanent barrier against oxidation and moisture. This preliminary protective action eliminates the need for costly ongoing storage and operation controls, resolving the contradiction between chemical stability and process cost.
Solution Approach 2:
The protective shell provides self-service protection to the lithium metal, making the system inherently stable without requiring external control systems or monitoring. This self-protecting mechanism maintains chemical stability while minimizing additional process costs.
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
Enables safe and efficient storage and operation of lithium batteries under normal conditions, reducing costs and preventing structure breakdown, while maintaining reversible efficiency and conductivity.
Implementation Method 1
a protection layer which is disposed next to the outer surface of the lithium active material and entirely covers the lithium active material, wherein the protection layer comprises a metal which is capable of alloying with the lithium metal or the lithium ions
Implementation Method 2
The composite layer effectively blocks the lithium active material from the surroundings so that the moisture and the oxygen would not contact with the lithium active material
Implementation Method 3
a structural layer which at least partially covers the outer surface of the protection layer, wherein the structural layer comprises a material having no moisture and no oxygen
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3C
AI summary
An active material is disclosed in the present invention. The active material includes a lithium active material and a complex shell which completely covers the lithium active material. The complex shell includes at least one protection covering and at least one structural stress covering. The protection covering is a kind of metal which may alloy with the lithium ion. The structural stress covering dose not alloy with the lithium active material. The complex shell efficiently blocks the lithium active material out of the moisture and the oxygen so that the lithium active material is able to be stored and operated in the general surroundings. The structural stress provided via the structural stress covering may keep the configuration of the active material unbroken after the repeating reactions.