How to improve the performance of lithium batteries through sandwich and drilling processes?

　　Through the improvement of the two processes of sandwiching and drilling, the energy density of the lithium battery can be greatly increased, and the power storage and charging speed can be increased by ten times.

　　Northwestern University professor Dr. Harold Kong once published an article in "Advanced Energy Materials" magazine, giving a detailed introduction to the "sandwich" and "drilling" technologies to improve the energy storage and charging efficiency of lithium batteries.

　　Sandwich technology improves energy storage efficiency

　　Lithium ions in lithium-ion batteries are located between the "graphene" of the battery's positive electrode material. "Graphene" is a layer of stacked carbon atoms, and lithium ions are located between these carbon layers. Lithium battery charging is the process of sending lithium ions to the positive electrode of the battery. The opposite is true when discharging or working. Therefore, the storage capacity of a lithium-ion battery is determined by the number of lithium ions that can reach the positive electrode.

　　Generally speaking, in traditional "graphene" lithium-ion batteries, every six carbon atoms can hold one lithium atom. In order to increase energy storage, scientists have tried to replace carbon with silicon. Because every four silicon atoms can hold one lithium atom, in theory, replacing carbon with silicon can achieve more than 30% of the energy storage.

　　But silicon has a shortcoming, that is, it will expand and contract during charging and discharging, and it may break when the power is high, which will damage the battery and cause the battery to lose power quickly.

　　Sandwich technology came into being, its method is: small silicon clusters are sandwiched between two carbon layers, thereby generating new "graphene" containing silicon atoms. The result is that the carbon layer of graphene and silicon clusters expand and contract together during charging and discharging, without breaking, which effectively increases the energy density of the battery, so that the storage capacity can be increased under the premise of stable battery structure.

　　Drilling technology improves charging efficiency

　　Charging is the process in which lithium ions enter the center of the positive graphene sheet, that is, the shorter the time the lithium ions are in place, the faster the charging and the higher the efficiency. Therefore, it is the shape of the graphene that affects the charging efficiency.

　　The traditional graphene sheet is a thin-film structure with a thickness of only one atom, which makes its area very large. When charging a lithium battery, lithium ions must move forward from the edge of the graphene to climb between the two graphene sheets, that is, the two carbon layers. If a large number of lithium ions crawl to the middle zone at the same time, it will inevitably cause congestion, which will affect the extension of the charging time.

　　Drilling technology is to open up multiple paths for these lithium ions by drilling holes in graphene, and one more channel will double the efficiency. The specific method is to drill millions of small holes with a diameter of 10-20 nanometers in the carbon layer. Due to oxidation, lithium ions can pass through the battery more freely without blocking, thereby improving the charging efficiency .

　　Through the improvement of the above two processes, the energy density of the lithium battery can be greatly increased, and the power storage and charging speed can be increased ten times.