Advanced Nanoporous Separators for Stable Lithium Metal Electrodeposition at Ultra-High Current Densities in Liquid Electrolyte

Abstract

Lithium (Li) metal is considered as the ultimate anode material for the development of next-generation batteries.1 However, Li metal electrode forms dendritic structure after cycling which causes an internal short circuit.2, 3 In this work, we grew mesoporous silica thin film (MSTF) with perpendicular nanochannels and ultra-small pore diameter (~5 nm diameter) onto the anodic aluminum oxide (AAO) membrane as the MSTF⊥AAO separator. The nanoporous MSTF⊥AAO separator with novel inorganic structures shows stable Li deposition for more than 1600 h of operation in Li-Li cells under a very high current density and capacity of 10 mA cm–2 and 5 mAh cm–2. The separator gives improved rate capability in Li-NMC batteries. The excellent performance of the MSTF⊥AAO nanoporous separator is due to good wetting of electrolytes, straight nanopores, uniform deposition of Li and blocking the finest dendrite. Our designed separators provide a groundbreaking model to regulate Li plating/stripping behavior. References Cheng, X.-B.; Zhang, R.; Zhao, C.-Z.; Zhang, Q., Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review. Chem. Rev. 2017, 117 (15), 10403-10473.Xu, W.; Wang, J.; Ding, F.; Chen, X.; Nasybulin, E.; Zhang, Y.; Zhang, J.-G., Lithium metal anodes for rechargeable batteries. Energy Environ. Sci. 2014, 7 (2), 513-537.Zhang, S. S., A review on the separators of liquid electrolyte Li-ion batteries. Power Sources 2007, 164 (1), 351-364.