Anode-Free Lithium Battery Shielding Oxide Layer
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Solution Overview
Problem
Lithium metal batteries face challenges due to the reactivity of lithium, leading to surface oxide layer formation, which reduces electric conductivity and inhibits lithium ion movement, causing increased electric resistance and shortening the battery's service life.
Innovation Solution
An anode-free battery structure is developed where a lithium metal layer is formed on the negative electrode current collector during charging, using a gel polymer electrolyte and a high-irreversible lithium metal compound to prevent exposure to the atmosphere and inhibit oxide layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as a negative electrode to achieve high weight energy density, then the battery capacity is improved, but the reactivity of lithium causes surface oxide layer formation which reduces electric conductivity and increases electric resistance
Solution Approach 1:
A protective layer is introduced as an intermediary between the lithium metal negative electrode and the atmospheric environment. This protective layer prevents direct contact between lithium metal and oxygen/moisture, thereby preventing oxide layer formation while maintaining the high energy density benefits of lithium metal.
Solution Approach 2:
The battery is designed to create an inert atmosphere environment that prevents oxidation of lithium metal. By controlling the internal atmosphere to be free of oxygen and moisture, the lithium metal surface remains clean and conductive, resolving the contradiction between high energy density and maintained conductivity.
2Ease of manufacture
If lithium metal is exposed to atmosphere during battery assembly, then the assembly process is simplified, but surface oxide layer formation occurs which inhibits lithium ion movement and increases electric resistance
Solution Approach 1:
The protective layer is applied to the lithium metal negative electrode before battery assembly. This preliminary action protects the lithium surface during the assembly process, allowing simplified manufacturing procedures while preventing oxide layer formation that would otherwise occur during exposure to atmosphere.
Solution Approach 2:
The protective layer serves as a mediator that enables the lithium metal to be handled and assembled in normal atmospheric conditions without forming harmful oxide layers. This intermediary protection allows ease of manufacture while maintaining lithium ion movement capability.
3Reliability
If vacuum deposition process is used to form lithium negative electrode to reduce oxide layer formation, then reactivity problem is partially improved, but the process complexity increases and oxide layer formation cannot be fundamentally inhibited
Solution Approach 1:
Instead of using complex vacuum deposition equipment, a simple protective layer is applied to the lithium metal surface. This disposable-like protective coating provides sufficient protection during assembly and operation, avoiding the need for expensive and complex vacuum deposition processes while fundamentally preventing oxide layer formation.
Solution Approach 2:
The approach changes from controlling the assembly environment (vacuum deposition) to protecting the lithium surface directly (protective layer). This parameter change in the protection strategy simplifies the process while achieving fundamental prevention of oxide layer formation.
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
This approach shields the lithium metal from atmospheric oxygen and moisture, improving cycle life characteristics and maintaining high energy efficiency by preventing surface oxide layer formation, thus enhancing the battery's performance and service life.
Implementation Method 1
lithium metal is formed on the negative electrode current collector in the negative electrode by moving from the positive electrode through initial charging
Implementation Method 2
the electrolyte is a gel polymer electrolyte and lithium metal is formed on the negative electrode current collector in the negative electrode by moving from the positive electrode through initial charging
Data Source
AI summary
A lithium secondary battery which is made of an anode-free battery and comprises lithium metal formed on a negative electrode current collector by charging. The lithium secondary battery comprises the lithium metal formed in a state of being shielded from the atmosphere, so that the generation of a surface oxide layer (native layer) formed on the negative electrode according to the prior art does not occur fundamentally, thereby preventing the deterioration of the efficiency and life characteristics of the battery.