Insertion/extraction of lithium and sodium in transition metal oxides and chalcogenides

Abstract

Lithium and sodium can be reversibly inserted into a variety of transition metal oxide and chalcogenide hosts at low temperatures. The reaction is essentially topochemical involving electron-transfer and accompanying diffusionless transformation of the anion array in many cases. Alkali metal insertion/extraction reactions provide new routes for the synthesis of novel solids exhibiting unusual structure and properties. It appears that while the structure of the insertion compound is determined by the host structure and the size of the alkali metal ion, the extent of insertion/extraction is decided by the redox characteristics and electronic conductivity of the host.