Lithiophilic perovskite-CaTiO3 engineered separator for dendrite-suppressing 5 V-class lithium metal batteries with commercial carbonate-based electrolyte

High theoretical specific capacity and the lowest electrochemical potential of Li metal have made it one of the most promising materials for metal anode. Nonetheless, shortened lifespan and even safety issues induced by uncontrollable growth of Li dendrite severely impede the development of lithium metal batteries (LMBs). In this work, a facile and economic strategy is introduced by casting lithiophilic CaTiO3 micro-particles onto the commercial polyethylene separators. The CaTiO3 coating could not only enhance the thermal stability of the separator, but also decrease the nucleation overpotential and facilitate homogeneous Li deposition, finally achieving suppression of the Li dendrite. Consequently, with the CaTiO3-coated separators, the cycling lifespan of Li||Li symmetric cells was remarkably improved to 1500 h in carbonate electrolyte. Moreover, 5 V-class full cells coupled with CaTiO3-coated separators exhibit prolonged lifespan and superior rate performance, indicating the good potential of the modified separators for application. Considering the fabrication of CaTiO3-coated separators is completely industry-available, this work could accelerate the proceeding of practical application of high-energy-density lithium metal battery systems.