Atomistic Modelling of the Lithium-Based NASICON-Type Electrolyte LiZr2(PO4)3

LiZr2(PO4)3 (LZP) is a promising solid-state electrolyte for lithium-ion batteries owing to its structurally stable NASICON-type framework and potential for rapid Li-ion conduction. In this study, classical atomistic simulations were employed to investigate intrinsic defect formation, Li-ion migration and dopant incorporation in LZP. The Li Frenkel defect was found to be the most energetically favourable intrinsic defect process, with a formation energy of 0.40 eV. The next most favourable process was the Li–Zr antisite cluster, in which Li and Zr ions exchange their lattice positions, with an energy of 1.67 eV. A very low migration activation energy of 0.05 eV was calculated for Li-ion transport within the (bc) plane, indicating potentially high ionic mobility. Among the isovalent dopants examined, Na and Ce were the most favourable substitutions at the Li and Zr sites, respectively. Moreover, substitution of Ca or Y at the Zr site promotes the formation of charge-compensating Li interstitials, which could increase the concentration of mobile Li ions and thereby enhance ionic conductivity.