Crystalline Structure and Lithium-Ion Channel Formation in Self-Assembled Di-lithium Phthalocyanine:  Theory and Experiments

The crystalline Structure of di-lithium phthalocyanine (Li2Pc) is analyzed via a sequence of theoretical methods starting with ab-initio optimizations of a single molecule and dimers, followed by a series of classical molecular dynamics simulations that emulate four alternative crystalline structures. Calculated X-ray spectra are compared with those from experiments, and the results suggest that the features correspond to a dominant beta-phase, although similarities in the calculated spectrum of alternative phases may imply the possible existence of polymorphism in this material. Since Li2Pc has been proposed as a solid electrolyte for lithium-ion batteries, the existence of ion-conducting channels is examined through the analyses of the simulated structures. Dynamical properties Such as the lithium-ionic diffusion coefficient are determined through the velocity autocorrelation function and compared to experimental values.