Layered cathode for improving safety of Li-ion batteries

To improve the safety performance of Li-ion batteries using LiCoO2 cathodes without sacrificing battery capacity, a new electrode concept using a multilayered cathode as an alternative to a mixture of different kinds of powder is introduced. Results from a double-layered cathode consisting of a LiCoO2 main layer with a LiFePO4 sublayer on top of an aluminum current collector are presented. The mechanism of how the LiFePO4 layer improves the tolerance of the batteries against overcharging is discussed. (c) 2007 The Electrochemical Society.