Photon Prelithiation of Graphite Anodes Without Copper Corrosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion battery cells face issues such as irreversible capacity loss during the first charge/discharge cycle, copper corrosion due to overcharging, handling difficulties with lithium-rich anodes, and the inability to reuse lithium-coated anodes due to lithium plating, which complicates the fabrication process and increases costs.
Innovation Solution
A method for prelithiating an anode using a lithium reservoir and photon irradiation, where positively charged lithium ions are intercalated into the graphite structure through a combination of Lorentz force and electron emission, forming covalent bonds, thereby avoiding copper corrosion and enabling anode reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional prelithiation processes utilize excess lithium metal incorporated into the active anode material, then the lithium reservoir is formed, but process costs increase and handling becomes difficult due to high reactivity requiring dry environment
Solution Approach 1:
The patent introduces a polymer electrolyte as an intermediary layer between the lithium metal and the anode active material. This mediator allows lithium ion transport while preventing direct contact between lithium metal and the environment, eliminating the need for dry room conditions and simplifying handling procedures
Solution Approach 2:
The patent replaces the mechanical handling requirements for lithium metal (which necessitates dry environment and special precautions) with a chemical/electrochemical system where lithium ions are transported through a polymer electrolyte. This substitution eliminates the need for complex environmental controls and special handling procedures
2Quantity of substance
If lithium metal is used for prelithiation, then lithium reservoir is achieved, but the entire electrode fabrication process including coating must take place in a dry environment, increasing energy costs
Solution Approach 1:
The polymer electrolyte acts as a protective intermediary that allows the lithium metal to be handled and processed in normal atmospheric conditions. This eliminates the need for energy-intensive dry room environments during electrode fabrication, coating, and assembly processes
3Quantity of substance
If anode is overcharged to create lithium reservoir, then lithium is available, but copper substrate corrodes leading to pitting and reduced adhesion and conductivity
Solution Approach 1:
The polymer electrolyte serves as a protective intermediary layer that prevents direct contact between the lithium metal and the copper current collector. This intermediary layer allows lithium ion transport while preventing electrochemical reactions that would cause copper corrosion and pitting
Solution Approach 2:
The patent applies a preliminary protective action by placing the polymer electrolyte layer between the lithium metal and copper substrate before any corrosion can occur. This preliminary protection prevents the harmful electrochemical reactions that would otherwise damage the copper current collector
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 method reduces irreversible capacity loss, prevents copper corrosion, simplifies handling, and allows for the reuse of lithium-coated anodes by converting lithium into covalent bonds, enhancing Coulombic efficiency and anode capacity.
Implementation Method 1
Prelithiation is carried out by photon irradiation. During photon irradiation, electrons are ejected from the metallic lithium of the lithium reservoir, while the positively charged lithium ions remain.
Implementation Method 2
The anode is moved through a magnetic field during pre-lithiation, generating a Lorentz force acting on the anode. This force separates the electrons to the outer surface of the anode exposed to photon irradiation.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a method for prelithiating an anode or anode precursor (10) for a lithium-ion battery cell, which is formed from a current collector foil (11) and an active material layer (13) coated thereon, wherein the active material layer (13) comprises a lithium reservoir (19) containing metallic lithium for carrying out the prelithiation, and wherein, during the prelithiation, positively charged lithium ions intercalate from the lithium reservoir (19) into the graphite structure of the active material layer (13). According to the invention, prelithiation is carried out by photon irradiation (24) onto the lithium reservoir (19), whereby electrons are released from the lithium reservoir (19), leaving behind positively charged lithium ions that intercalate into the relatively negative graphite structure of the anode material layer (13).