Li-Ion Negative Electrode with Pre-Lithiated Conductive Layer
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Solution Overview
Problem
Lithium ion secondary batteries face issues of decreased adhesion of the negative electrode plate and low first discharge capacity due to uneven lithium precipitation and undesired reactions, which are not effectively addressed by direct pre-lithiation of the negative electrode current collector.
Innovation Solution
Incorporating a pre-lithiated conductive layer between the negative electrode active material and the current collector, with a thickness of 1 to 50 μM, composed of pre-lithiated materials like carbon black or lithium foil, to enhance adhesion and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct pre-lithiation of the negative electrode current collector is adopted, then lithium dendrite formation is reduced, but adhesion of the negative electrode plate decreases and first discharge capacity is reduced
Solution Approach 1:
The invention segments the pre-lithiation function by introducing a separate pre-lithiation layer between the current collector and the negative electrode active material layer. This layer contains lithium powder that can be released to prevent dendrites, while the adhesive layer maintains strong bonding between components. The segmentation allows each layer to perform its specific function without compromising overall electrode integrity.
Solution Approach 2:
The invention introduces an intermediary pre-lithiation layer that mediates between the current collector and the negative electrode active material. This intermediate layer contains lithium powder that reacts with the electrolyte to form SEI and release lithium ions, preventing dendrite formation on the current collector, while the adhesive layer ensures strong mechanical bonding. The intermediary structure resolves the conflict between dendrite prevention and adhesion maintenance.
2Stability of the object's composition
If direct pre-lithiation of the negative electrode current collector is adopted, then lithium ion distribution is improved, but first discharge capacity is reduced
Solution Approach 1:
The pre-lithiation layer performs preliminary lithium ion release before the negative electrode active material is fully utilized. The lithium powder in the pre-lithiation layer reacts with the electrolyte during initial cycles to form SEI and release lithium ions, ensuring proper lithium ion distribution. This preliminary action compensates for lithium loss without consuming the active lithium in the negative electrode material, thereby preserving first discharge capacity.
Solution Approach 2:
The invention applies local quality by concentrating the lithium powder specifically in the pre-lithiation layer rather than uniformly distributing it throughout the entire negative electrode. This localized placement ensures that lithium ions are released at the critical interface between the current collector and electrolyte where dendrites form, while the negative electrode active material retains its full lithium content for high discharge capacity.
3Strength
If a pre-lithiated conductive layer is introduced, then adhesion and conductivity are enhanced, but electrode structure complexity increases
Solution Approach 1:
The invention merges multiple functions into a single pre-lithiated conductive layer that combines both conductive material and lithium powder. This integrated layer simultaneously provides electrical conductivity for electron transport and lithium ion release for dendrite prevention, while the adhesive properties ensure strong bonding. The merging approach simplifies the overall electrode structure compared to having separate layers for each function.
Solution Approach 2:
The pre-lithiated conductive layer serves multiple functions: it provides electrical conductivity through the conductive material, releases lithium ions through the lithium powder to prevent dendrites, and ensures mechanical adhesion between the current collector and negative electrode active material. This multi-functional design reduces the number of separate components needed while maintaining all essential electrode functions.
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 pre-lithiated conductive layer improves the adhesion and conductivity of the negative electrode, resulting in enhanced first discharge capacity and initial cycle efficiency of the lithium ion secondary battery.
Implementation Method 1
the pre-lithiated conductive layer comprises a lithium diffusion region
Implementation Method 2
coating the conductive material slurry on the negative electrode current collector, and curing to form a pre-lithiated conductive layer
Data Source
AI summary
The present invention provides a negative electrode of lithium ion secondary battery, a preparation method thereof and a lithium ion secondary battery. The negative electrode of the lithium ion secondary battery comprises a negative electrode active material, a pre-lithiated conductive layer and a negative electrode current collector. By using the negative electrode of lithium ion secondary battery, the preparation method thereof and the lithium ion secondary battery of the present invention, technical effects of excellent electrochemical performance, especially excellent first discharge capacity and first time efficiency are achieved, and excellent negative electrode plate binding force is achieved.