Salt-Bridge Pre-Lithiation for SEI-Safe Lithium Ion Supply
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Solution Overview
Problem
The direct contact between a lithium source, such as a lithium metal sheet or lithium metal powder, and an electrolyte solution during pre-lithiation leads to the production of byproducts that cause damage to the solid electrolyte interphase (SEI) layer on the negative electrode, resulting in side reactions and degradation of the lithium secondary battery's cycle capacity retention.
Innovation Solution
A pre-lithiation apparatus is designed with two reaction vessels connected by a salt bridge containing a high-concentration electrolyte and organic solvent, separating the lithium source and the negative electrode, preventing byproducts from contaminating the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lithium source is dipped in an electrolyte solution for pre-lithiation, then lithium ions can be supplied to the negative electrode, but byproducts are produced that damage the SEI layer and cause side reactions
Solution Approach 1:
The pre-lithiation apparatus is divided into two separate reaction vessels: a first reaction vessel containing the negative electrode and electrolyte solution, and a second reaction vessel containing the lithium source and electrolyte solution. The vessels are connected by a salt bridge, allowing lithium ions to transfer from the second vessel to the first vessel without direct contact between the lithium source and the negative electrode, thereby preventing byproduct formation while maintaining lithium ion supply.
Solution Approach 2:
A salt bridge serves as an intermediary component connecting the two reaction vessels. It allows lithium ions to pass through from the lithium source vessel to the negative electrode vessel while preventing direct contact between the lithium source and negative electrode, thus eliminating the harmful byproduct generation pathway while preserving the beneficial lithium ion transfer.
2Manufacturing precision
If a lithium source is in direct contact with the negative electrode in electrolyte solution, then pre-lithiation can be performed, but the SEI layer on the negative electrode surface is damaged
Solution Approach 1:
The system separates the pre-lithiation process into two spatially distinct reaction vessels connected by a salt bridge. This segmentation allows controlled lithium ion transfer to achieve pre-lithiation while preventing direct contact that would damage the SEI layer, thus maintaining both manufacturing precision and electrode reliability.
Solution Approach 2:
The salt bridge acts as an intermediary that enables controlled lithium ion transfer for pre-lithiation while preventing direct contact between the lithium source and negative electrode. This intermediary mechanism preserves SEI layer integrity while achieving the desired pre-lithiation effect.
3Productivity
If byproducts are produced during pre-lithiation, then lithium ions are supplied to the negative electrode, but side reactions occur during charge/discharge cycles
Solution Approach 1:
By segmenting the pre-lithiation system into two separate reaction vessels connected by a salt bridge, the invention enables efficient lithium ion supply to the negative electrode while preventing the formation of byproducts that would cause side reactions during subsequent charge/discharge cycles, thus improving cycle capacity retention.
Solution Approach 2:
The salt bridge serves as an intermediary that facilitates lithium ion transfer for efficient pre-lithiation while blocking the pathway for byproduct formation and subsequent side reactions, thereby maintaining high productivity and improving battery reliability over multiple cycles.
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 prevents the degradation of the negative electrode's SEI layer, enhancing the lithium secondary battery's performance by maintaining higher initial coulombic efficiency and capacity retention over multiple cycles.
Implementation Method 1
the electrolyte solution of the first reaction vessel and the electrolyte solution of the second reaction vessel are linked to each other by a salt bridge, the salt bridge includes an electrolyte and an organic solvent
Data Source
Figure 1~2
AI summary
Provided is a pre-lithiation apparatus which prevents an electrode from being damaged by the byproducts produced by contact between a lithium source, such as a lithium metal sheet or lithium metal powder, and an electrolyte for pre-lithiation. The pre-lithiation apparatus includes two reaction vessels of a first reaction vessel and a second reaction vessel, wherein the electrolyte solution of the first reaction vessel and the electrolyte solution of the second reaction vessel are linked to each other by a salt bridge, a negative electrode to be pre-lithiated is dipped at least partially in the electrolyte solution of the first reaction vessel, and a lithium source capable of supplying lithium ions is dipped at least partially in the electrolyte solution of the second reaction vessel.