Electrochemical performances of BiSbO4 as electrode material for lithium batteries

We present an electrochemical study of BiSbO₄, an opened layered oxide having a structure related to Aurivillius phases. Li//BiSbO₄ cells show a large specific capacity as high as 1250 mAh g⁻¹ during reduction down to 0.5 V. This reaction involves 18Li atoms per formula unit, pointing it towards a very promising cathode material for primary lithium batteries, in particular for ICD devices. The characterization of the reduction products indicates that the reduction of BiSbO₄ with lithium presumably goes along firstly with the formation of metallic Sb and Bi to follow the formation of the alloys Li₃Bi and Li₃Sb dispersed in a lithium oxide matrix. In situ X-ray diffraction experiments proved the amorphous nature of both metals and final alloys. On the other hand when Li//BiSbO₄ cells are limited to discharge down to 1.2 V, BiSbO₄ reacts with 5Li atoms. After the first discharge, that develops a specific capacity of 350 mAh g⁻¹, high cyclability has been observed.