Lithium Secondary Battery with In-Situ Lithium Metal Anode Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium metal batteries face challenges due to lithium's high reactivity, leading to surface oxide layer formation and dendrite growth, which decreases electric conductivity and battery lifetime, especially during assembly when lithium is exposed to the atmosphere.
Innovation Solution
A lithium secondary battery design featuring a negative electrode current collector with a lithium metal layer formed by lithium ion migration from the positive electrode after charging, and an electrolyte system with two layers of differing ion conductivity to suppress dendrite growth and prevent atmospheric exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as a negative electrode material, then weight energy density and capacity are improved, but surface oxide layer formation occurs due to high reactivity with atmosphere
Solution Approach 1:
The patent applies preliminary action by forming a protective coating layer on the lithium metal surface before battery assembly. This coating is applied in advance to prevent atmospheric exposure and oxide layer formation during subsequent handling and operation, thereby preserving the high energy density benefits while eliminating the reactivity problem.
Solution Approach 2:
The patent creates an inert environment by using a protective coating that acts as a barrier between the reactive lithium metal and the atmospheric environment. This coating establishes an inert interface that prevents oxygen and moisture from reaching the lithium surface, thus preventing oxide layer formation while maintaining the electrode's high capacity.
2Object-affected harmful factors
If vacuum deposition process is used to form lithium negative electrode, then surface oxide layer formation is partially improved, but fundamental suppression is still impossible due to atmospheric exposure during assembly
Solution Approach 1:
The patent applies preliminary action by pre-coating the lithium metal with a protective layer before assembly. This preliminary protection eliminates the need for complex vacuum deposition processes during assembly, as the oxide prevention is already in place, thereby reducing process complexity while maintaining protection effectiveness.
Solution Approach 2:
The protective coating acts as an intermediary layer between the lithium metal and the atmospheric environment. This mediator prevents direct contact between lithium and atmosphere during assembly operations, eliminating the need for complex vacuum processes while fundamentally suppressing oxide layer formation.
3Ease of manufacture
If lithium foil is attached on current collector, then negative electrode structure is formed, but manufacturing and use are difficult due to lithium reactivity
Solution Approach 1:
The protective coating serves as an intermediary layer that is applied to the lithium foil before attachment to the current collector. This coating reduces lithium reactivity with atmosphere and other components, making the manufacturing process easier and safer while maintaining the electrode structure formation capability.
Solution Approach 2:
The protective coating creates an inert environment around the lithium foil, preventing reactive interactions with atmospheric oxygen and moisture during manufacturing and use. This enables easier handling and assembly operations while maintaining the functional integrity of the negative electrode.
4Reliability
If oxide layer is present on lithium surface, then electric conductivity decreases, but this is caused by insulator film formation
Solution Approach 1:
The patent applies preliminary anti-action by preventing the formation of the harmful insulator film through pre-application of a protective coating. This coating prevents the chemical reactions that would form oxide layers, thereby maintaining electric conductivity from the outset rather than attempting to remove or penetrate existing insulator films.
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 design effectively blocks surface oxide layer formation and significantly reduces dendrite growth, enhancing battery cycle lifetime and performance by maintaining lithium metal in a stable, conductive state within the battery.
Implementation Method 1
lithium ions migrate from the positive electrode after charging to form a lithium metal layer on the negative electrode current collector
Implementation Method 2
the electrolyte comprises a first electrolyte layer and a second electrolyte disposed on the first electrolyte layer, wherein the first electrolyte layer has higher ion conductivity than the second electrolyte layer, and dendrite growth is suppressed by a difference in the ion conductivity
Data Source
AI summary
A lithium secondary battery including a positive electrode, a negative electrode comprising a negative electrode current collector, and an electrolyte disposed between the positive electrode and the negative electrode; and a lithium metal layer on the negative electrode current collector in the negative electrode. The electrolyte includes a first electrolyte layer and a second electrolyte disposed on the first electrolyte layer, wherein the first electrolyte layer faces the negative electrode, and the second electrolyte layer faces the positive electrode. The first electrolyte layer has higher ion conductivity than the second electrolyte layer, and wherein the lithium metal layer is formed by migration of lithium ions from the positive electrode after charging.