samples were calculated and plotted together with the specific surface bet area of the samples as a function of the grinding time as in fig5 through 12 these data confirm the earlier noted expectation that irreversible capacity loss could be a function of bet surface area since the measured irreversible loss tracks exceptionally well the measured bet surface area for all the carbon samples independently of the type of grinding system used such a correlation is particularly striking for the impact ground graphite samples where both irreversible loss and bet surface reach maxima simultaneously also for such samples another correlation occurs between surface area and structural parameters namely that when the bet surface area goes through such a maximum the d 002 lattice spacing increases rapidly as seen in fig2 and 3 thus it was additionally noted that advantageously the u03b4x rev in contrast to the u03b4x irrev increases with grinding time independently of the bet surface area a significant accomplishment of the present invention is that by mechanical grinding of carbons whether graphite soft carbon coke or hard carbon one can obtain materials which may be incorporated into electrolytic cell electrodes capable of intercalating lithium at an average voltage of 1 v vs li with as little as a 35 irreversible loss during the first discharge yet able to sustain a reversible capacity approaching 2 li per 6 carbons upon subsequent cycling on the other hand the reversible lithium capacity u03b4x rev in contrast to the irreversible capacity u2262 x irrev shows little direct correlation with the bet surface area and will regularly increase with grinding time independently of.