1.Composite material structure
Lithium-carbon composite material (Li-CNT) is based on lithium metal and CNTs, in which lithium metal is impregnated in CNT particles that are as the framework.
The surface passivated lithium-carbon composite material (SP@Li-CNT) has a hydrophobic and oxygen-repellent layer, and its processibility is improved. The material can be used safely in a dry room.
Compared with lithium foil, Li-CNT or SP@Li-CNT can provide more lithium plating and stripping sites, inhibit the formation of dendrites, and ease the volume change of the electrode. The CNT framework provides a stable support for SEI, so the anode has better cycle performance.
2.Physical and chemical properties：
CNT is the common commercial multi-walled carbon nanotubes, and lithium is battery-grade metallic lithium and various lithium alloys. The particle size, D50=9 microns, is basically the same as commercial graphite and silicon carbon anode materials.
3.Sample application examples
Li-CNT or SP
@ Li-CNT are mixed with binder and conductive agent, and then coated on Cu foil to prepare electrodes.
The SP@Li-CNT obtained by OPA passivation is paired with lithium iron phosphate to form a full cell, with an anode excess of 50%. The cell can be cycled stably for 250 times. The coulombic efficiency of the anode is 98.8%.
The SP@Li-CNT with optimized passivator constitutes a full cell with lithium iron phosphate. The anode is 50% excessive; the lifetime is improved to more than 300 cycles; and the coulombic efficiency is increased to 99.25%.
On the basis of optimizing the passivating agent, adjusting the electrolyte additives can further improve the cycle performance and rate performance of the anode. The coulombic efficiency can reach 99.3%, and the 10C rate charge and discharge still maintain good capacity performance.
4. Emergency measures
Lithium has high chemical activity and burns violently when exposed to water. Li-CNT is a micron-level particle with stronger reaction activity and will spontaneously ignite in air. SP@Li-CNT after passivation is still flammable and cannot be stored in air or used in non-dry air. If there is a fire, only use fire-fighting sands and fire blankets to extinguish the fire (see MSDS for details).
5. Sample provision method
A small amount of sample is currently available.
The glass bottle is filled with argon and sealed. Then the bottle is sealed in the iron cans and aluminum plastic bags. Filled the bag with foam, and shipped in wooden boxes or iron drums.
7. Safety instructions
7.1 Operating environment:：
Lithium-carbon composite material: only allowed to be used in an argon glove box (water content ≤1ppm, oxygen content ≤1ppm).
Surface passivated lithium-carbon composite material: only allowed to be used in dry room with dew point≤-45℃ or in argon glove box (water content≤1ppm, oxygen content≤1ppm).
7.2 Safety rules for personnel
Protective equipment such as masks, dry nitrile gloves, dry protection suits and dry protective goggles should be worn when handling samples.
7.3 Transfer sample to argon glove box
Remove the express cartons, iron cans and fillings, and transfer the remaining parts directly to the glove box through the transition bin.
When pumping and filling in the transition bin, it is necessary to reduce the pumping vacuum (-0.5MPa is sufficient) and increase the pumping and filling
times (6-10 times) to prevent the package from breaking.
After transferring to the glove box, continue to remove the aluminum-plastic bag.
7.4 Storage of remaining samples
The remaining samples are sealed and stored in an argon glove box.
7.5 Waste disposal
Wear protective equipment when disposing of waste. The nitrile gloves, dust-free paper and other items used in the operation shall be fully immersed with water in an open space or in a fume hood. After the metal lithium and water have completely reacted, make sure that no hydrogen bubbles will be generated; then dispose the solid and liquid waste.