Lithium Transport in Solid Conductors

Lithium ion batteries (LIBs) have received increasing attention during the past decades due to their high energy density and low self-discharge, and have become the dominant power source for portable electronics. However, LIBs today still suffer from safety issues, one of which being the flammability of typical organic liquid electrolytes. This is a serious concern for electrical vehicles. Generally, replacing liquid electrolytes with inorganic solid electrolytes may solve this problem. However, the ionic conductivities of most solid electrolytes are several orders of magnitude lower than that of liquid electrolytes, limiting their practical use. In our group, we use atomistic simulation techniques (e.g. density functional theory, ab initio/classical molecular dynamics) to investigate the transport of defects in ionic conductors. Under the framework of density functional theory, we are able to calculate defect formation energies, migration barrier, and extract information from electronic structures. We also simulate larger systems and obtain self-diffusivity of Li ions via classical molecular dynamics simulations. By combining the two techniques, we aim at gaining better understanding into the ion conduction as well as develop large-scale material pre-screening methods to save cost and labor for experimentalists.

Reference:
Z. Lu, C. Chen, Z.M. Baiyee, X. Chen, C. Niu, and F. Ciucci. Defect Chemistry and Lithium Transport in Li3OCl Anti-Perovskite Superionic Conductors. Physical Chemistry Chemical Physics, 17, 32547-32555 (2015) link