we would like to introduce for you our nano SILICON particle which could be used in the negative material of the lithium battery. Compared with other negative materials such as graphite, mesocarbon microbeads, petroleum coke which have been in commercialized use, the alloy Si-Li, Sn-Li, Al-Li has much more higher lithium storage than graphite which has theoretical value 372 mAh/g. The value of alloy Sn-Li is 990 mAh/g, Al-Li 990 mAh/g, Si-Li 4200 mAh/g. Now the alloy as negative material of the secondary lithium battery becomes popular research point. I believe that your company must make research in this area and I am sure that the particle size of silicon you use is about 1um.
Our company is the leading manufacturer of nano carbide and nano nitride particles. We have our own proprietary technology of production-----plasma arc vapor synthesis method. We use H2 to react SiCl4, then we get nano SILICON which is single- phase. Our product SILICON has four features of high purity, small particle, uniform diameter distribution, high surface activity, large specific surface area. At present in the world, we are the only one which realizes the industrial production of SILICON below 100 nm.
The specific parameter of our product SILICON is as followings:
Chemical formula: Si
APS: 50 nm
SSA: 80 m2 /g
Bulk density: 0.08 g /cm3
Color: Brown yellow
Shelf time: 24 months
Crystal types: Amorphism and crystalloid
The decrease of the size of silicon particle (below 100nm) could effectively decrease the expansion resulting from silicon absorbing the lithium ion, reduce the loss of silicon, and improve the recycle capacity. With the vapor method, the nano silicon particle has higher surface activity, easily to match with many kinds of material to form composite materials. As that it is more flexible in applications.
The way now in China to apply silicon particle in the negative material of lithium battery is : coat the surface of silicon with carbon material, then form Si-C composite material. As the matrix, the carbon not only could be embedded with Lithium, but also the transmission channel of electron and atom. Si-C composite material, the carbon matrix is unformly embedded in nano SILICON., and the crystal does not change before and after forming the composite material. Nano Si-C composite material not only has high recycle and stability character as the same with the carbon material, which could prevent the silicon material from activity loss of lithium embedded due to volume expansion and migration, but also has the feature of high specific capacity as the same with Si material.