Pre-Lithiated Negative Electrode with Concave Pattern for Low Initial Loss
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Solution Overview
Problem
Lithium secondary batteries face significant initial irreversible capacity loss due to the formation of a solid electrolyte interface (SEI) on the negative electrode, which reduces the battery's electrochemical performance and cycle life, and existing pre-lithiation methods are inefficient and costly for mass production.
Innovation Solution
A method of producing a negative electrode with a line-and-space lithium metal pattern that is ionized and diffused into the negative electrode active material layer, creating line-shaped concave portions, enhancing initial reversibility and impregnability of the electrolyte solution, using a pre-lithiation solution containing an ionizable lithium salt and organic solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-lithiation is performed by depositing lithium on the negative electrode, then initial irreversible capacity loss is reduced, but manufacturing cost increases and workability deteriorates
Solution Approach 1:
The patent applies preliminary action by forming a lithium metal pattern on the negative electrode before battery assembly. This pre-lithiation is performed during the electrode manufacturing process itself, allowing the lithium to be present and ready to compensate for SEI formation losses from the first charge cycle, thereby reducing initial irreversible capacity loss without requiring separate post-assembly treatment steps
Solution Approach 2:
The patent extracts the pre-lithiation function from complex deposition apparatus and separates it into a simple lithium metal pattern layer that can be applied during standard electrode manufacturing. By taking out the essential function of adding lithium and implementing it through a simple patterned layer rather than complex deposition, the method maintains high initial reversibility while dramatically improving ease of manufacture
2Reliability
If pre-lithiation is performed by directly contacting lithium with the negative electrode, then initial irreversible capacity loss is reduced, but manufacturing time increases
Solution Approach 1:
The patent merges the pre-lithiation step with the standard electrode manufacturing process. The lithium metal pattern is formed and contacted with the negative electrode active material layer during the same manufacturing sequence, eliminating the need for separate pre-lithiation treatment steps and maintaining high manufacturing speed while still achieving the benefit of reduced initial capacity loss
3Reliability
If conventional pre-lithiation methods are used, then initial capacity loss is addressed, but device complexity and cost increase
Solution Approach 1:
The patent uses a simple lithium metal pattern that can be easily applied and discarded during manufacturing. The lithium metal is placed in a patterned form on the electrode surface and serves its purpose of compensating for initial capacity loss, then remains as part of the electrode structure without requiring recovery or complex handling, thereby reducing both device complexity and manufacturing cost
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 approach improves the initial reversibility and electrochemical performance of lithium secondary batteries by reducing irreversible capacity loss and enhancing electrolyte impregnability, leading to better cycle characteristics and capacity retention.
Implementation Method 1
lithium metal ions are diffused into the negative electrode active material layer
Implementation Method 2
pre-lithiation solution containing an ionizable lithium salt and organic solvent
Data Source
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AI summary
The present invention relates to a negative electrode for a lithium secondary battery, a method of producing the negative electrode, and a lithium secondary battery including the negative electrode. Specifically, the negative electrode of the present invention can reduce the initial irreversibility of the negative electrode because lithium metal ions are diffused into the negative electrode active material layer by pre-lithiation, and the negative electrode active material layer into which the lithium metal ions are diffused includes a plurality of line-shaped concave portions, so that when the lithium secondary battery is produced later, the concave portion keeps an electrolyte solution therein well to improve the impregnability of the electrolyte solution, thereby ultimately improving the electrochemical performance of the lithium secondary battery.