Dual-Scale Al2O3 Particles Coating for High-Performance Separator and Lithium Metal Anode

Herein, the polyethylene (PE) separators are coated by micro/nanoalumina particles. The alumina particles with different sizes play different roles. The microalumina mainly enhances the thermal stability of the polyolefin separator and provides large channels for lithium-ion diffusion. The nanoalumina particles are helpful in improving the lithium-ion transference number by increasing the contact interface area of electrolyte/alumina. The lithium-ion transference number of the separators with different coatings increases from 0.32 to 0.40, mainly due to the ratio of micro/nanoalumina particles. Meanwhile, ion conductivity increases from 0.30 to 0.40 mS cm −1 . As a result, the cycling stability of the lithium metal anode is greatly improved by the synergetic effect of microsized alumina particles and nanosized alumina particles.