Negative Electrode Pre-Lithiation Under High-Pressure Electrolyte Control
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Solution Overview
Problem
Existing pre-lithiation methods for negative electrodes in secondary batteries suffer from non-uniform pre-lithiation due to changes in the composition of the pre-lithiation solution caused by solvent volatilization, leading to reduced battery efficiency and cycle lifespan.
Innovation Solution
A pre-lithiation apparatus and method that utilizes a high-pressure chamber surrounding the pre-lithiation reactor to maintain a pressure exceeding atmospheric pressure, preventing solvent volatilization and maintaining a constant solution composition, thereby ensuring uniform pre-lithiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-lithiation is performed using a conventional open reactor, then the pre-lithiation process can be completed, but the solvent in the pre-lithiation solution volatilizes causing non-uniform pre-lithiation and reduced battery efficiency
Solution Approach 1:
The patent applies an inert atmosphere principle by sealing the reactor and maintaining a controlled environment to prevent solvent volatilization. The reactor is equipped with a sealing mechanism that creates a closed system, preventing the pre-lithiation solution from contacting atmospheric conditions that would cause evaporation. This ensures uniform pre-lithiation by maintaining consistent solution composition throughout the process.
Solution Approach 2:
The patent converts the potential harm of solvent volatilization into a benefit by using the volatilization tendency to drive the reaction forward while simultaneously capturing and reusing the solvent vapors. The sealed reactor system allows the solvent to reach equilibrium without loss, and the condensed vapors can be returned to the solution, maintaining constant composition and improving pre-lithiation uniformity.
2Quantity of substance
If pre-lithiation is performed with prolonged reaction time to ensure completeness, then more lithium is inserted into the negative electrode, but solvent volatilization increases causing non-uniform pre-lithiation
Solution Approach 1:
The sealed reactor system maintains an inert, controlled atmosphere that prevents solvent volatilization even during prolonged pre-lithiation reactions. This allows extended reaction times to maximize lithium insertion into the negative electrode without the adverse effect of solvent loss, ensuring both completeness and uniformity of pre-lithiation.
Solution Approach 2:
The patent implements continuous pre-lithiation by maintaining the sealed reactor environment throughout the entire reaction period. The continuous presence of the pre-lithiation solution in contact with the negative electrode, without interruption or solvent replenishment, enables sustained lithium insertion while preventing volatilization losses that would occur in open systems.
3Ease of manufacture
If the pre-lithiation solution is exposed to atmosphere during the process, then the process is simple and open, but the composition ratio of solvents changes due to volatilization
Solution Approach 1:
The patent employs a sealed reactor that creates a controlled, inert environment for the pre-lithiation process. While this adds some complexity compared to open systems, it maintains constant solution composition by preventing atmospheric exposure and solvent volatilization. The sealing mechanism and controlled atmosphere ensure that the solvent composition ratio remains stable throughout the reaction.
4Reliability
If lithium metal is disposed on two surfaces of the negative electrode to pre-lithiate all active material layers, then complete pre-lithiation is achieved, but the device complexity increases
Solution Approach 1:
The patent uses the pre-lithiation solution as an intermediary medium that facilitates uniform lithium distribution across the negative electrode. Instead of requiring complex multi-surface lithium metal disposal, the solution-based approach allows lithium ions to diffuse uniformly through the electrolyte and insert into the negative electrode active material, achieving complete pre-lithiation with simpler electrode structure.
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 effectively prevents non-uniform pre-lithiation, enhancing the initial efficiency and cycle characteristics of secondary batteries by maintaining a stable SEI film formation.
Implementation Method 1
a high-pressure chamber surrounding the pre-lithiation reactor and where an internal air pressure of the high-pressure chamber exceeds an atmospheric pressure
Implementation Method 2
a method of connecting lithium metal with the negative electrode and electrochemically charging the negative electrode
Data Source
AI summary
An apparatus for pre-lithiating a negative electrode includes a pre-lithiation reactor having a pre-lithiation solution accommodated therein, a high-pressure chamber surrounding the pre-lithiation reactor, wherein an internal air pressure of the high-pressure chamber is configured to exceed atmospheric pressure, at least one lithium metal counter electrode disposed in the pre-lithiation solution, the lithium metal counter electrode being disposed to face a negative electrode receivable in the pre-lithiation solution in a state that the lithium metal counter electrode is spaced apart from the negative electrode by a predetermined interval, and a charge and discharge unit being connectable to the negative electrode and the lithium metal counter electrode to provide a circuit.