The most recent developments in intercalation chemistry concern both f
undamental research and applications. They include the study of new ho
st materials, such as fullerenes and new oxide structures, and of gues
t species, such as peroxides or mercury. They promote a better underst
anding of the intercalation process at the atomic scale. In trying to
define precisely the nature of the charge transfer, an important effor
t has also been devoted to understanding guest-host interactions. Deci
sive progress has been made in the field of applications related to re
chargeable batteries.