DENSITY OF STATES IN GRAPHITE FROM ELECTROCHEMICAL MEASUREMENTS ON LIX(C1-ZBZ)6

Using electrochemical methods we have measured the variation of the chemical potential-mu of intercalated Li in graphite and in boron-substituted graphite as a function of Li concentration x. For small x in Li(x)(C1-zBz)6, mu can be predicted from the density of one-electron levels versus energy, and we find good agreement with the data for pure graphite and for a boron-doped sample. In the rigid-band model, dx/d-mu vs mu is directly proportional to the density of states versus energy, and our measurements of dx/d-mu agree well with empirical tight-binding density-of-states calculations. We show how the values of tight-binding overlap interactions can be directly determined from the electrochemical data.