Artificial nucleation sites with stable SEI for Li metal anodes by aggressive Al pulverization

Abstract

Uneven nucleation and fragile solid electrolyte interphase (SEI) restrict the practical application of lithium (Li) metal anode. A versatile strategy to simultaneously overcome these two drawbacks is critical for Li metal batteries (LMBs). Herein we propose an “aggressive aluminum (Al) pulverization” strategy to form abundant artificial nucleation sites and robust SEI films adjacently, leading to homogeneous Li deposition/stripping and high Li Coulombic efficiency. A core-shell structure with Al core and alumina-silica (Al 2 O 3 –SiO 2 ) shell, Al@Al 2 O 3 –SiO 2 (AAS), could be easily synthesized, by modulating the chemical diffusion of silicon (Si) element towards Si–Al alloy surface. The active SiO 2 sites not only contribute to form the robust SEI layer, but also facility the lithiation of the AAS, accelerating the conversion of reversible Li–Al alloy into inert Li 3 Al 2 phase. The as-generated AAS with Li 3 Al 2 and Li 12 Si 7 phases possess negligible Li nucleation over-potential (~0.7 mV), serving as an optimal structure for dendrite-free Li plating/stripping with a prolonged life-span of 6 times longer than that of the unprotected counterpart in carbonate electrolytes. Uniform Li deposition and robust SEI films have been enabled by an Al@Al 2 O 3 -SiO 2 core-shell structure via an aggressive Al pulverization strategy for stable Li metal anodes. • A core-shell structure Al 2 O 3– SiO 2 by modulating the chemical diffusion of Si element towards Si–Al alloy surface. • A structure with abundant artificial nucleation sites and robust SEI films for Li metal protection. • Stable cycling of Li||LiNi 0.88 Co 0.09 Al 0.03 O 2 full cells with a high NCA loading of 5 mAh cm −2 .