Pre-Lithiation Chamber Water Capture for SEI Protection
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Solution Overview
Problem
The challenge in the field of lithium secondary batteries is controlling the water content in the pre-lithiation atmosphere to prevent damage to the solid electrolyte interphase (SEI) film on the negative electrode, which is difficult due to high water content in dry rooms, leading to unwanted reactions and loss of lithiated state.
Innovation Solution
A pre-lithiation reaction chamber apparatus is designed with a water-capturing vessel containing water-capturing powder and a position-changing member, such as a rotating shaft or agitation fan, to maintain water content below 10 ppm, ensuring effective pre-lithiation of the negative electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-lithiation is carried out in a dry room atmosphere, then the pre-lithiation process can be performed, but the water content cannot be controlled below 10 ppm due to atmosphere introduction processes
Solution Approach 1:
A water-capturing vessel containing water-capturing powder is introduced as an intermediary substance between the dry room atmosphere and the pre-lithiation reaction vessel. This mediator actively removes water molecules from the atmosphere through adsorption, enabling the pre-lithiation process to proceed with water content controlled below 10 ppm despite the challenges of atmosphere introduction
Solution Approach 2:
The physical state and concentration parameters of water in the pre-lithiation atmosphere are changed by introducing water-capturing powder. The powder adsorbs water molecules, transforming the atmosphere from a high-water-content state to a controlled low-water-content state (below 10 ppm), thereby resolving the contradiction between maintaining pre-lithiation reliability and controlling water content
2Ease of operation
If water content in the atmosphere is above 10 ppm, then the atmosphere is easier to maintain, but the SEI film on the negative electrode is damaged and lithium ions are oxidized
Solution Approach 1:
The water-capturing powder acts as an intermediary that selectively removes water from the atmosphere without interfering with the pre-lithiation reaction. This allows the atmosphere to be easily maintained while simultaneously protecting the SEI film by keeping water content below the damaging threshold of 10 ppm
Solution Approach 2:
The water-capturing powder creates an inert-like environment by actively removing water molecules that would otherwise react with the SEI film and lithium ions. This transformed atmosphere protects the sensitive electrochemical components while remaining easy to maintain
3Quantity of substance
If water reacts with lithium salt in the electrolyte, then the electrolyte can function, but byproducts such as PF5 are formed that break the SEI film
Solution Approach 1:
The water-capturing powder performs preliminary anti-action by removing water from the atmosphere before the water can react with the lithium salt in the electrolyte. This preventive measure stops the formation of harmful byproducts like PF5 before they can break the SEI film, while still allowing necessary lithium salt dissolution to occur
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 solution effectively inhibits damage to the SEI film, resulting in improved initial coulombic efficiency and cycle capacity retention for lithium secondary batteries by maintaining a controlled water environment during pre-lithiation.
Implementation Method 1
a water-capturing vessel, the water-capturing vessel including water-capturing powder
Data Source
AI summary
A pre-lithiation reaction chamber apparatus including a pre-lithiation reaction vessel which can prevent harmful effects caused by water that may be generated during pre-lithiation is provided. The pre-lithiation reaction vessel includes an electrolyte including a lithium salt, a negative electrode for a lithium secondary battery and a lithium ion-supplying member. Each of the negative electrode for the lithium secondary battery and the lithium ion-supplying member is at least partially in contact with the electrolyte. The pre-lithiation reaction chamber apparatus further includes a water-capturing vessel. The water-capturing vessel includes water-capturing powder, a container configured to receive the water-capturing powder, and a position-changing member configured to change a position of the water-capturing powder in the container.