Transfer Laminate Pre-Lithiation for Silicon Anode Cycle Life
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Solution Overview
Problem
The pre-lithiation process for silicon-containing negative electrodes in lithium secondary batteries faces challenges such as high initial irreversible capacity, volume change, and surface side reactions, leading to reduced battery capacity and cycle life, with existing methods like electrochemical pre-lithiation posing safety risks and increasing production costs.
Innovation Solution
A transfer laminate with a base layer, a release layer, and a lithium metal layer is used, where the release layer thickness is between 0.1 μm and 10 μm, and the average surface roughness of the base layer is 50 nm or greater, facilitating efficient and uniform lithium transfer and pre-lithiation without lithium loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-containing negative electrode active material is used to improve energy density, then capacity is improved, but initial irreversible capacity increases and cycle life is reduced
Solution Approach 1:
The patent applies preliminary action by performing pre-lithiation of the silicon-containing negative electrode active material before battery assembly. This is achieved through contact with a lithium metal-containing transfer laminate during electrode manufacturing, which adds lithium reserves to compensate for the initial irreversible capacity loss. This preliminary lithium addition ensures that sufficient lithium remains available for subsequent charging-discharging cycles, thereby improving cycle life while maintaining the high energy density benefit of silicon-containing materials.
2Quantity of substance
If electrochemical pre-lithiation method is used to reduce initial irreversible capacity, then battery capacity is improved, but safety risks increase due to fire and explosion hazards
Solution Approach 1:
The patent uses an intermediary approach by introducing a lithium metal-containing transfer laminate as a mediator between the silicon-containing negative electrode active material and the electrolyte. This transfer laminate enables lithium transfer through a physical contact method during electrode manufacturing, avoiding the need for electrochemical reactions in the electrolyte. This intermediary mechanism achieves the desired pre-lithiation effect while eliminating the safety risks associated with electrochemical pre-lithiation methods.
3Manufacturing precision
If electrochemical pre-lithiation is performed to control initial irreversible capacity, then capacity uniformity is improved, but production cost increases
Solution Approach 1:
The patent employs a cost-effective approach by using a disposable lithium metal-containing transfer laminate that can be integrated into the electrode manufacturing process. This transfer laminate serves as a single-use pre-lithiation tool that can be applied during standard electrode production, eliminating the need for additional expensive electrochemical pre-lithiation equipment and processes. The method achieves uniform capacity control while maintaining production cost efficiency.
4Quantity of substance
If lithium metal transfer process is used for pre-lithiation, then initial irreversible capacity is reduced, but lithium metal safety and transfer difficulty increase
Solution Approach 1:
The patent uses the transfer laminate as an intermediary carrier that simplifies lithium metal transfer. Instead of directly handling and transferring reactive lithium metal, the lithium is deposited on the transfer laminate in a controlled manner during manufacturing. The transfer laminate acts as a safe intermediary that enables controlled lithium transfer to the negative electrode while minimizing safety risks and operational difficulties associated with direct lithium metal handling.
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 enables more efficient and uniform pre-lithiation of the negative electrode active material layer, reducing lithium loss and improving battery capacity and cycle life while ensuring safety and reducing production costs.
Implementation Method 1
a friction coefficient between the release layer and the base layer is 0.05 or less
Implementation Method 2
transferring a lithium metal layer by laminating the transfer laminate onto a surface of the negative electrode active material layer
Data Source
AI summary
The present application relates to a transfer laminate, a negative electrode for a lithium secondary battery, a method for manufacturing a lithium secondary battery, and a lithium secondary battery.