Criticality of the phase transition on stage two in a lattice-gas model of a graphite anode in a lithium-ion battery.

Herein, a Monte Carlo study within the canonical assembly has been applied to elucidate the lithium-ion phase transition order of a stage II lithium-graphite intercalation compound (LiC12 ) around the critical point. The results reveal a weakly first-order phase transition at 354.6 ± 0.5 K via measurements that follows the power laws with effective exponents. The graphite-lithium system was emulated within a lattice-gas model, comprising specific insertion sites arranged in four parallel planes with a triangular geometry. Moreover, two different types of energetic interactions were used: a Lennard-Jones potential, for particle interactions in the same plane, and a power law potential that decreased with distance, for particles in different planes. The energy per site and order parameter distribution were used to classify the order of the transition. Furthermore, the order parameters, susceptibility, and heat capacity were computed and analyzed.