Guiding Uniform Sodium Deposition through Host Modification for Sodium Metal Batteries

Abstract

Room‐temperature Na metal batteries represent an emerging energy storage technology beyond Li‐ion batteries, owing to the high specific capacity and high natural abundance of Na. However, Na metal anodes are plagued with multiple challenges including unstable solid electrolyte interphase, undesirable dendrite growth, and large volumetric expansion, leading to low Coulombic efficiency during Na plating and stripping. To this end, mechanically stable and sodiophilic hosts with nano‐ or micro‐structured materials have been investigated to accommodate Na in the structured spacing or gaps for enhanced cyclability. In this concept, we will discuss the key concepts and latest developments in guiding uniform Na deposition through host modification, especially carbon, inorganic and polymeric materials. Future prospects and outlook will also be provided, including artificial interphase design, solid‐state electrolytes, and precise nanoscale characterization to improve our fundamental understanding of Na deposition and spur this burgeoning field in Na metal batteries.

Progress in the development of solid-state electrolytes for reversible room-temperature sodium–sulfur batteries

“…67,68 Stable interfaces provide uniform deposition of sodium, which mitigates dendritic growth over the anode. 69 The stability of the SEI is related to the chemical nature of electrolytes; the chemical composition of products formed at the interface decides the electrochemical performance and life of a cell. 22,70 It has been reported that Na-S batteries with organic solvent-free solid-state electrolytes, having a wide electrochemical stability window, can effectively prevent diffusion and shuttling of sodium polysulfide to the anode while inhibiting the dendrite growth.…”

“…67,68 Stable interfaces provide uniform deposition of sodium, which mitigates dendritic growth over the anode. 69 The stability of the SEI is related to the chemical nature of electrolytes; the chemical composition of products formed at the interface decides the electrochemical performance and life of a cell. 22,70…”

Exploration of the Unique Structural Chemistry of Sulfur Cathode for High‐Energy Rechargeable Beyond‐Li Batteries

“…[78,79] In contrast, RT-Na/S delivers a high theoretical specific energy density of 1230 Wh kg À1 with long-term sustainability and safety besides low cost and abundance. [80][81][82][83] The viability of RT-Na/S batteries is severely challenged by the highly corrosive nature of its discharge products, which are identified to be more alkaline than their Li counterparts. [84] In addition to that, the shuttle phenomena are exacerbated in RT-Na/S battery, resulting in higher volumetric fluctuations, i.e., about 170% (in contrast to 70% of volumetric changes in the Li/S system).…”

Microarchitectures of Carbon Nanotubes for Reversible Na Plating/Stripping Toward the Development of Room‐Temperature Na–S Batteries

“…[14,15] The hostless nature of the sodium metal anode causes volume change upon stripping/plating, leading to repeated loss of the metal anode and electrolyte inventory. [16] The dendrite growth, which is associated with local current density variation at the surface, is also affected by the hostless nature of the sodium metal anode. Unlike lithium metal dendrites, the sodium dendrites are much weaker, dissociate from the metal surface, and affect the Na metal inventory, causing a sharp decay of the CE.…”

“…Besides that, the sodium metal anode can be stabilized through 3D hosts or current collectors, which can alter the local deposition to control dendrite growth. [16,23] The carbon-based materials have widely been examined as the potential host for the sodium metal anode. [24,25] Many other 3D porous carbon-based materials, for instance, carbon paper with N-doped CNT, [26] carbon fibers, [27] carbon felt, [28] reduced graphene oxides, [29] SnO 2 -CNF, [30] and rGO with MXene, [31] DOI: 10.1002/ente.202200742 An ordered and homogeneous deposition of sodium metal is pivotal in achieving reversible and long-term stability of the metal battery.…”