Lithium-Supplementing Composite Diaphragm for In-Situ Battery Pre-Lithiation
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Solution Overview
Problem
Current pre-lithiation methods for lithium-ion batteries are costly, dangerous, and require stringent environmental conditions, leading to reduced production efficiency and poor coulombic efficiency and cycle performance.
Innovation Solution
A lithium-supplementing composite diaphragm is introduced, comprising a diaphragm layer, a lithium metal layer, a first protective layer, and an electronic conductive layer, which provides conductive channels and isolates the lithium layer from the environment, allowing in-situ SEI formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pre-lithiation methods (electrochemical, chemical, lithium foil, or stabilized lithium metal powder) are used, then lithium supplementation is achieved, but production efficiency decreases and costs increase due to added processes and stringent environmental requirements
Solution Approach 1:
The patent combines the pre-lithiation function with the diaphragm structure by depositing lithium metal layer directly onto the diaphragm. This integration eliminates separate pre-lithiation steps while maintaining lithium supplementation effectiveness, thereby preserving production efficiency without requiring additional process steps or stringent environmental controls
Solution Approach 2:
The diaphragm is designed to serve multiple functions simultaneously: it acts as a physical separator between electrodes, provides structural support, and delivers lithium supplementation through the integrated lithium metal layer. This multi-functionality eliminates the need for separate pre-lithiation processes, maintaining high production efficiency while achieving reliable lithium supplementation
2Reliability
If lithium metal is used for pre-lithiation, then lithium supplementation is achieved, but safety risks increase due to flammability and explosiveness
Solution Approach 1:
The patent introduces protective layers as intermediary barriers between the lithium metal layer and the external environment. These protective layers prevent direct contact between lithium metal and air/moisture, eliminating safety hazards while maintaining the lithium supplementation function. The diaphragm structure itself also serves as a protective barrier, further enhancing safety
Solution Approach 2:
The protective layers are applied in advance to the lithium metal layer before the battery is assembled and activated. This preliminary protection prevents harmful reactions between lithium metal and the environment from occurring in the first place, ensuring safety while maintaining lithium supplementation stability
3Reliability
If lithium foil method is used, then pre-lithiation is achieved, but lithium utilization rate decreases due to low efficiency
Solution Approach 1:
The lithium metal layer is deposited directly onto the diaphragm surface in controlled thicknesses, creating a localized and precise lithium source. This ensures that lithium is released exactly where needed (at the electrode-dia phragm interface) in the required amounts, maximizing utilization rate and preventing waste through uncontrolled lithium consumption
4Reliability
If negative electrode pre-lithiation is performed, then initial coulombic efficiency improves, but device complexity increases due to additional processes and environmental controls
Solution Approach 1:
The pre-lithiation function is merged into the diaphragm structure itself through the integrated lithium metal layer. This eliminates the need for separate pre-lithiation equipment, process steps, and environmental control systems, thereby improving initial coulombic efficiency without increasing device or process complexity
Solution Approach 2:
The diaphragm with integrated lithium metal layer automatically provides lithium supplementation during normal battery operation without requiring external intervention or specialized processing equipment. The lithium is released naturally through the diaphragm structure during charging/discharging cycles, improving initial coulombic efficiency through a self-service mechanism that adds no complexity to the manufacturing process
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
Improves initial coulombic efficiency and cycle life of lithium batteries by stable lithium supplementation without altering production processes or environmental requirements, reducing lithium loss and enhancing utilization rates.
Implementation Method 1
an electronic conductive layer, arranged on the side of the lithium metal layer close to the negative electrode layer, and configured to provide an electronic conductive channel between the lithium metal layer and the negative electrode layer
Implementation Method 2
a diaphragm layer, configured to isolate the negative electrode layer and the positive electrode layer
Implementation Method 3
a first protective layer, arranged on the side of the lithium metal layer close to the negative electrode layer
Data Source
AI summary
A lithium-supplementing composite diaphragm for lithium batteries, a lithium battery, and a preparation method thereof are provided. The lithium battery includes negative and positive electrode layers. The lithium-supplementing composite diaphragm is arranged therebetween. The lithium-supplementing composite diaphragm comprises: a diaphragm layer, configured to isolate the negative and positive electrode layers; a lithium metal layer, arranged on the side of the diaphragm layer, and configured to supplement lithium to the negative electrode layer; a first protective layer, arranged on the side of the lithium metal layer; and an electronic conductive layer, arranged on the side of the lithium metal layer, and configured to provide an electronic conductive channel between the lithium metal layer and the negative electrode layer. Among them, the orthographic projections of the electronic conductive layer and the first protective layer on the lithium metal layer do not overlap or partially overlap.