  This work aims to study the insertion of AlCl_4^- anion in the crystalline
structure of oriented pyrolytic graphite (PG) at the point of view of the anion
itself. The electronic and atomic structures of the anion at different
intercalation stages are studied. In particular double-edge (bicolor) X-ray
absorption spectroscopy at the Al and Cl K-edges is carried out, highlighting a
contraction of the anion bonding at the highest intercalation degree obtained
electrochemically (stage 3), while the electronic population changes for both
the edges upon cycle.
