According to reports, Hitachi uses a newly developed silicon-based material to form the battery's negative electrode, which can double the battery density. At the Second Wearable Expo in Tokyo from January 13 to 15, 2016, Hitachi will showcase lithium-ion batteries made with new technology.
Hitachi calls the new technology "ULSiON", which uses "SiO-C" as the negative electrode active material. SiO-C is a composite material coated with a carbon coating on the surface of SiO. For a long time, the use of silicon as a negative electrode active material has faced a problem. It will expand and contract during charging and discharging. The task of researchers is to reduce its expansion and contraction to a certain level. Hitachi has now solved this problem.
By using new materials, Hitachi can compress the width of lithium-ion batteries to 13 millimeters or less. Under the same size, the energy density of new batteries is twice as high. The new battery can also be charged at different voltages. Hitachi predicts that the end-of-discharge voltage of the battery will be reduced to 2.0V. Under low voltage, the discharge curve of the battery made with the new technology is more stable. The lower the end-of-discharge voltage of the battery, the more power it can hold and the better its performance.
Hitachi has put new batteries into commercial products, such as smart phones. The new battery can also be used in wearable devices as a laminated battery. Only small batteries can be used in some compact devices, and the market demand for new Hitachi batteries will become very large in the future.