MLi₂Ti₆O₁₄ (M = Sr, Ba, and Pb): new cathode materials for magnesium-lithium hybrid batteries

Magnesium-lithium hybrid batteries (MLHBs) are playing an increasingly important role in energy storage systems owing to their abundant raw materials and favorable safety characteristics. Consequently, MLi2Ti6O14 (M = Sr, Ba, and Pb) compounds have been synthesized via a sol-gel method, followed by calcination. For the first time, as cathodes for MLHBs, MLi2Ti6O14 (M = Sr, Ba, and Pb) showed good electrochemical properties. For example, at 50 mA g-1, the specific capacities of MLi2Ti6O14 (M = Sr, Ba, and Pb) after 300 cycles are 75.6, 68.2 and 76.3 mA h g-1, respectively. In addition, MLi2Ti6O14 (M = Sr, Ba, and Pb) also possess outstanding rate performances. Importantly, the ion storage mechanism of MLi2Ti6O14 (M = Sr, Ba, and Pb) compounds in MLHBs was studied with PbLi2Ti6O14 as the representative. These results reveal that MLi2Ti6O14 (M = Sr, Ba, and Pb) have good electrochemical reversibility, and can be used as cathodes for MLHBs.