Li6Zn3(BO3)4: a new zincoborate featuring vertex-, edge- and face-sharing LiO4 tetrahedra and exhibiting reversible phase transitions

Abstract

A new lithium zincoborate Li₆Zn₃(BO₃)₄ has been successfully prepared via a high-temperature solution method. Li₆Zn₃(BO₃)₄ is composed of LiO₄ and ZnO₄ tetrahedra, and nearly coplanar BO₃ units. A face-sharing LiO₄ configuration was found in the title compound, and a comparison of Li–O configurations was systemically investigated for all Li-containing borates. Interestingly, Li₆Zn₃(BO₃)₄ has two reversible phase transitions at about 341 and 706 °C, which implies that Li₆Zn₃(BO₃)₄ is a potential candidate as a phase change material. In situ high-temperature X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis were used to verify the two reversible phase transitions. The linear optical properties were researched in detail using ab initio density functional theory (DFT).