Bronzes show promise for use as cathodes in lithium batteries

Phosphate tungsten bronzes have been tested as cathodes in electrochemical lithium insertion cells

Since their discovery in 1830 the tungsten bronzes have been extensively studied due to their interesting chemical, electrical and optical properties. An interesting structural feature at the molecular level is the presence of long, empty tunnels. These tunnels can have other ions inserted into them to enhance and alter the properties of the base material.

This study, published in AZojomo*, by A. Martínez-de la Cruz, F. H. Guillén Garza, U. Ortiz Méndez and Leticia M. Torres-Martínez from Universidad Autónoma de Nuevo León, looked at the electrochemical insertion of lithium into the tunnels of some diphosphate tungsten bronzes. This was done in order to assess their potential as cathodes for use in lithium batteries.

An electrochemical study of the lithium insertion through potentiostatic and galvanostatic experiments was carried out. Due to the high oxidation state of the tungsten in the oxides the amount of lithium inserted in alkali phosphate tungsten bronzes was large, but due to irreversible processes, specific capacity of the cells were dramatically lost after the first cycle. Taking this behaviour into account it is suggested that these bronzes can be considered as a cathode in primary lithium batteries.