Structural and electrochemical properties of layered manganese dioxides in relation to their synthesis: classical and sol–gel routes

Abstract

Specific structural, physical and electrochemical features of layered manganese dioxides either containing or not containing sodium, are examined and discussed in relation to their synthesis route: classical (precipitation reactions) and sol–gel. Classical-route compounds give rise to poor electrochemical behaviour, whereas sol–gel-route compounds are among the most promising rechargeable manganese dioxides for lithium batteries. These results are related to the type of symmetry, which results from stacking of the layers, and to the nature of the host site for the interlamellar cationic species. It is shown that the best conditions for lithium electrochemical insertion correspond to the initial existence of a hexagonal structure with trigonal prismatic sites.