of the mcmb graphite active material the graphite electrode was fabricated by solvent casting a slurry of mcmb2528 graphite binder and casting solvent mcmb2528 is a mesocarbon microbead material supplied by alumina trading which is the u s distributor for the supplier osaka gas company of japan this material has a density of about 2 24 grams per cubic centimeter a particle size maximum for at least 95 by weight of the particles of 37 microns median size of about 22 5 microns and an interlayer distance of about 0 336 as in the case of the cathode the binder was a copolymer of polyvinylidene difluoride pvdf and hexafluoropropylene hfp in a wt ratio of pvdf to hfp of 88 12 this binder is sold under the designation of kynar flex 2801 u00ae showing it 39 s a registered trademark kynar flex is available from atochem corporation an electronic grade solvent was used the slurry was cast onto glass and a free standing electrode was formed as the casting solvent evaporated the electrode composition was approximately as follows on a dry weight basis 85 graphite 12 binder and 3 conductive carbon a rocking chair battery was prepared comprising the anode the cathode and an electrolyte the ratio of the active cathode mass to the active anode mass was about 2 14 1 the two electrode layers were arranged with an electrolyte layer in between and the layers were laminated together using heat and pressure as per the.