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

Abstract

An ordered and homogeneous deposition of sodium metal is pivotal in achieving reversible and long‐term stability of the metal battery. The sodium deposition critically depends on the local interfacial properties of the anode/electrolyte interface. Due to the hostless nature of sodium metal anode, the integrity of the interface deteriorates rapidly, leading to a rise in stripping/plating overpotential or premature cell failure. Herein, well‐ordered microarchitectures of carbon nanotubes (MACNTs) as a potential host for reversible and highly stable stripping/plating of sodium metal are reported. Besides accommodating sodium metal, the MACNT host facilitates the formation of inorganic‐rich solid–electrolyte interphase over the sodium metal anode. As a result, it can achieve stripping/plating reversibility for 1200 h at a current of 1 mA cm−2. An overpotential of about 30 mV occurs for the stripping/plating process, indicating uniform and compact deposition of sodium. Moreover, when applying to a room‐temperature Na–FeS2 battery, the MACNT host achieves stable cycling for over 200 cycles at 200 mA g−1 and delivers a capacity of about 210 mA h g−1.

Patterned interlayer enables a highly stable and reversible sodium metal anode for sodium-metal batteries

“…A decrease in stripping/plating overpotential can be achieved; 12 however, long-term stability of the sodium metal anode remains challenging due to the formation of a thick SEI. 13 While the extrinsic approach leads to long-term stability of the sodium metal anode, it is not able to ensure smooth and uniform sodium stripping/plating 14–16…”

“…A decrease in stripping/plating overpotential can be achieved; 12 however, long-term stability of the sodium metal anode remains challenging due to the formation of a thick SEI. 13 While the extrinsic approach leads to long-term stability of the sodium metal anode, it is not able to ensure smooth and uniform sodium stripping/plating [14][15][16] While the strategies mentioned above are designed to either stabilize the SEI or control the sodium metal stripping/plating process, they are primarily focused on sodium metal and electrolytes. To date, only a handful of attempts have been made to address or stabilize the alkali metal anode by modifying the anode/separator interfacial region.…”