Electrochemical study of the reaction of lithium with Aurivillius and related phases

Some Aurivillius and Sillen phases have been tested as positive electrode materials for secondary lithium batteries through an electrochemical study. We have carried out an electrochemical and structural study of the lithium reaction with some of the most representative phases of the systems WO3-Bi2O3, MoO3-Bi2O3, and Nb2O5-Bi2O3. Although the amount of lithium atoms incorporated in all cases was large, due to irreversible structural transformations in the matrix of the host, specific capacity of the cells were dramatically lost after the first cycle. On the basis of in situ X-ray diffraction data of lithiated phases, we propose a mechanism of reaction.