Lithium Anode with Silane Protective Layer for Dendrite Suppression
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Solution Overview
Problem
Lithium secondary batteries face challenges with dendrite formation, safety issues, and limited capacity and lifespan when using lithium metal or lithium alloy as an anode active material, and existing anode materials like SiOx and carbon-based materials have limitations in improving charging/discharging cycles and capacity.
Innovation Solution
An anode for lithium secondary batteries is developed using a combination of an electrolytic copper foil current collector, an anode active material layer with lithium powder, and a protective layer formed by silane coupling processing, which suppresses dendrite formation and enhances safety and lifespan, allowing for a high-capacity battery with a large anode width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal or lithium alloy is used as anode active material, then high capacity is achieved, but dendrite formation occurs causing safety issues and reduced lifespan
Solution Approach 1:
A protective layer comprising a silane coupling agent is introduced as an intermediary between the lithium powder and the electrolyte. This protective layer prevents direct contact and reaction between lithium and electrolyte, suppressing dendrite formation while maintaining high capacity. The silane coupling agent forms a stable interface that mediates the interaction between the anode active material and electrolyte.
Solution Approach 2:
The anode is constructed as a composite structure combining copper foil current collector, lithium powder anode active material layer, and silane coupling agent protective layer. This composite material approach integrates the high capacity of lithium with the protective properties of the silane coupling agent, achieving both high capacity and improved safety/lifespan characteristics.
2Reliability
If SiOx is used as anode active material, then safety is improved, but charging/discharging cycle characteristics cannot be sufficiently improved
Solution Approach 1:
The invention changes the key parameter from using SiOx (silicon oxide) to using lithium powder with a silane coupling agent protective layer. This parameter change maintains safety improvements while dramatically enhancing charging/discharging cycle characteristics, achieving over 1000 cycles with less than 20% capacity degradation.
Solution Approach 2:
The silane coupling agent acts as an intermediary protective layer that enables lithium powder to achieve both high safety and excellent cycling characteristics. This mediator prevents direct lithium-electrolyte contact that would otherwise lead to dendrite formation and capacity degradation over cycles.
3Stability of the object's composition
If carbon-based material is used as anode active material, then expansion and contraction are suppressed, but capacity is decreased and initial charging/discharging efficiency is lowered
Solution Approach 1:
The silane coupling agent protective layer serves as an intermediary that enables lithium powder to maintain structural stability during charging/discharging cycles while preserving its high capacity. The protective layer accommodates volume changes and prevents degradation, allowing lithium powder to achieve both stability and high capacity.
Solution Approach 2:
The composite structure of lithium powder combined with silane coupling agent protective layer achieves the benefits of both materials: the structural stability and expansion/contraction suppression of protective coatings, combined with the high capacity of lithium powder, without the capacity limitations of carbon-based materials.
4Reliability
If protective layer is added to suppress dendrite formation, then safety and lifespan are improved, but device complexity increases
Solution Approach 1:
The protective layer is implemented as a thin film coating of silane coupling agent on the lithium powder surface. This thin film approach provides effective dendrite suppression and safety improvement while adding minimal structural complexity and maintaining simplicity in the overall device design.
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 provides a lithium secondary battery with improved energy density, cycling efficiency, and safety, while maintaining a low resistance value over time, and is applicable for various electronic devices with enhanced process efficiency.
Implementation Method 1
a protective layer which is provided while being coated on the anode active material layer
Implementation Method 2
a battery in which lithium ions participate in an oxidation-reduction reaction in an anode
Data Source
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AI summary
The present invention is related to an anode for a secondary battery, a method of manufacturing the same, and a lithium secondary battery using the same, the anode including: an electrolytic copper foil current collector; an anode active material layer which is provided on a single surface or both surfaces of the electrolytic copper foil current collector and includes lithium powder; and a protective layer provided on the anode active material layer, in which a thickness of the electrolytic copper foil current collector is 2 µm to 20 µm, and a thickness of the anode active material layer and the protective layer provided on the electrolytic copper foil current collector is 100 µm or less.