Homogeneous Na Deposition Enabling High‐Energy Na‐Metal Batteries

Abstract

Sodium (Na) metal as an anode is one of the ultimate choices for the high‐energy rechargeable batteries in virtue of its intrinsic high theoretical capacity (1166 mAh g−1) and low redox potential (−2.71V vs standard hydrogen electrode (SHE)), as well as its low cost and broad sources. Nevertheless, the dendrite‐related hazards seriously block its practical application. Na dendrite formation mainly emanates from the uncontrolled Na deposition behavior. Therefore, it seems particularly important to employ appropriate strategies towards the homogeneous deposition of Na for the dendrite‐free metal anode. In this review, the challenge of regulating Na homogeneous deposition for dendrite‐free Na anodes is first discussed. Then, recent advances in the strategies of regulating the Na uniform deposition are summarized, including adjusting Na+ flux near the solid‐liquid interface and improving sodiophilicity on the biphase interface. Lastly, perspectives on further research and important factors toward the practical application of high‐energy‐density Na metal batteries are emphasized in detail.

Kinetics and Pore Formation of the Sodium Metal Anode on NASICON‐Type Na3.4Zr2Si2.4P0.6O12 for Sodium Solid‐State Batteries

“…In particular, to increase the energy density of current sodium-ion batteries huge efforts are made to replace hard carbon (roughly 530 mAh g −1 ) [2] with the sodium metal anode (1165 mAh g −1 ). [3,4] However, side reactions and the formation of dendrites leading to capacity loss, short circuits, and cell failure have so far prevented the use of sodium metal anodes in room temperature liquid electrolyte-based batteries. [5] Inorganic ceramic solid electrolytes (SE) like Na-β″-alumina (BASE) or…”

A sodiophilic VN interlayer stabilizing a Na metal anode

“…In principle, the initial nucleation of Na plays a critically important role for the subsequent depositing behavior and the ultimate morphology characteristics of Na metal. 21,22 Thus, considerable research articles have been dedicated to regulating the initial Na nucleation behavior for dendrite-free SMAs. One of the effective approaches is physical implantation of nucleation seeds which can react with metal Na to form Na-rich alloys, benefiting the initial Na nucleation at specific sites.…”

Functionalized Halloysite Scaffold Controls Sodium Dendrite Growth

“…5,6 However, similar to Li, serious sodium dendrite growth not only causes safety problems but also hinders the practical application of the Na metal battery. 1,7,8 To date, several mechanisms have been proposed to reveal and predict the growth of dendrites. Among them, Sand's time is a well-known classic model for describing the initiation time of dendrite formation, proposed by Sand in 1901.…”

“…The secondary sodium metal battery with sodium as the anode has a far-higher energy density and power density than the conventional lithium-ion battery due to its extremely high theoretical specific capacity (1165 mAh g –1 ) and its appealing redox potential (−2.71 V vs the standard hydrogen electrode). , Meanwhile, Na is cheap, 2-3 orders of magnitude richer than lithium, and has comparable physical and chemical characteristics to Li. , Hence, sodium battery systems are considered a new type of high energy-density battery system, which can supplement or even replace the existing lithium battery system. , However, similar to Li, serious sodium dendrite growth not only causes safety problems but also hinders the practical application of the Na metal battery. ,, …”