Perovskite-type La0.6Sr0.4Co0.2Fe0.8O3−δ as an artificial interphase layer for dendrite-free Li metal anodes

Abstract

Lithium (Li) metal is considered as one of the most exciting anode materials for next-generation batteries because of its high theoretical capacity and lowest reduction potential. However, the uncontrollable dendrite growth associated with uneven deposition and huge volume change during cycling severely hampers its practical application in Li metal batteries. Herein, the lithiophilic perovskite-type La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) oxide is proposed as an artificial interphase layer to decorate copper directly for uniform Li deposition. The positively charged oxygen vacancies (PCOVs) originated from the LSCF can serve as natural electrostatic shield for Li deposition to the adjacent regions in order to achieve a uniform and dendrite-free Li deposition morphology. Moreover, LSCF nanoparticles can firmly affix to Cu foil surface through elements inter-diffusion at the LSCF/Cu interface during heat treatment process, which facilitate Li ion transport and accommodate Li deposition behavior. As a result, the LSCF decorated Cu foil (denoted as LSCF-Cu) exhibits stable Coulombic efficiency (CE) of 98.51% beyond 300 cycles in Li||Cu cells and stable Li plating/stripping for 2850 h with low hysteresis voltage of 15 mV in symmetric cells. Further, the full cell coupled with LiNi0.6Co0.2Mn0.2O2 (NCM) cathode (N/P is 4.17) exhibits a low polarization and prolonged cycle life. Therefore, this strategy will lay the foundation for designing advanced artificial interphase layer for dendrite-free Li and other metal batteries.