Nanostructured electrodes

Nanostructured electrodes for lithium ion batteries provide rapid battery recharge in a few minutes and a lifetime estimated to be more than twelve years. For electric vehicles, they enable rapid acceleration with an inherently safe design. Innovative nanostructured materials include lithium titanate spinel anode materials and manganate oxide spinel cathode materials. The spinel minerals are a class conforming to the MgAl2O4 crystal structure (from which the class is derived) and have the generic formula XY2O4. When placed together in a battery, they provide power and long life. Figure 1 compares the specific energies of standard lithium ion batteries, lead acid batteries, and batteries with nanostructure electrodes as a function of power density. For applications such as hybrid electric vehicles, electric vehicles, and power tools, the ability to deliver power is of critical importance. Experts have recognized for years the advantages of lithium ion technology over traditional power batteries, particularly those based on lead acid chemistry The prime advantage is that the lithium ion chemistry provides much higher energy density over lead acid. The rate of charging or discharging a battery at room temperature under constant current is expressed as total capacity, or C, divided by the time in hours. For example: 1C indicates that the battery is completely charged or discharged in one hour. In the same way, 0.2C indicates that the battery is completely charged or discharged in five hours. Up to now, for power applications (rates between 10 and 100 C) energy density has been severely reduced at high discharge rates for reasons explained below. However, the nanostructured electrode materials now offer, for the first time, a power-dense solution for passenger vehicles and other power applications.