Interface Design and Engineering for Sodium Metal Anode
Abstract
High theoretical capacity, low electrochemical potential, and abundant resources of metallic Na make it an appropriate candidate as the anode material in Na metal batteries (NMBs) and show its potential to complement Li-ion batteries. However, like its Li counterpart, the Na metal anode suffers from uneven plating/stripping behavior leading to dendrite growth, “dead Na” formation and even cell interior short-circuit. Another issue is the low Coulombic efficiency (CE) which results from the formation of unstable solid electrolyte interphase (SEIs) and continuous consumption of the electrolyte. This thesis mainly proposes an effective strategy to overcome the above shortcomings through the improvement of the Na electrode/electrolyte interface stability. Two types of hybrid artificial organic/inorganic SEI layers were developed on the surface of the Na metal anode using advanced atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques. The hybrid SEI can efficiently restrain the growth of Na dendrite and greatly improves the cycling stability performance. This thesis opens a new window to design the nanostructure interfaces for Na metal anodes for the next-generation NMBs.