Bulk metal hexacyanoferrate (MHCF) has been synthesized within the porous microstructure of conductive composite materials using a simple chemical procedure. The composite materials consist of micrometer-size graphite particles encapsulated in a SiO2 solid matrix using a sol-gel technique. A strong electrochemical signal from the chemically treated composites is associated with electrochemically switched alkaline-cation exchange. The exchange capacity of these composite electrodes exceeds by more than two orders of magnitude that of thin-film MHCF electrodes of comparable dimensions. The effects of some fabrication parameters on the cation-exchange capacity and on the distribution of the hexacyanoferrate within the composite electrodes are presented. (C) 2004 The Electrochemical Society.