(P,T) phase boundary in Li-intercalated graphite: Theory and experiment

Abstract
A simultaneous stage change and in-plane order-disorder transition is observed in dilute stage-2 Li-intercalated graphite either at low temperature or high pressure. Classical thermodynamics correctly predicts the observed slope of the equilibrium line in the (P,T) plane, justifying the Bragg-Williams approximation for the configurational entropy.