3D Confinement Strategy for Dendrite‐Free Sodium Metal Batteries

Abstract

Sodium metal batteries (SMBs) are attracting extensive attention for large‐scale energy storage due to the abundant reserves and low cost of sodium. However, the inevitable side reactions and uncontrollable dendrite growth in SMBs result in a continuous deterioration of the electrochemical performance and induce serious safety concerns, which severely restrict its practical application in the future. Among various improvement strategies, the 3D confinement strategy demonstrates great potential for stabilizing the Na anode owing to its optimized ion/electron transportation, lower deposition overpotential, and superior structural stability. Herein, first, the recent progress in SMBs which use the 3D confinement strategy to improve the electrochemical cycling stability of Na anode are outlined, and the potential regulation mechanism, including the transport/deposition behavior of Na+, interface engineering, and some advanced characterization techniques, are summarized. Furthermore, critical challenges and new perspectives are emphasized in detail. This review provides a deeper insight to enable construct ion of more comprehensive and effective Na metal anodes for advanced SMBs.

Atomic Sn–enabled high-utilization, large-capacity, and long-life Na anode

“…The pursuit of future energy-dense low-cost metal-based batteries (e.g., Na) has stimulated tremendous efforts in constructing robust interphases to tackle intrinsic interfacial instability, as ultimately being manifested as uncontrolled dendrite growth with serious performance deterioration ( 1 – 4 ). Approaches including optimizing electrolytes ( 5 , 6 ), constructing solid-state electrolytes ( 7 , 8 ), designing artificial protective layers ( 9 – 11 ), and engineering porous three-dimensional scaffolds ( 12 – 16 ) have thus been developed for various metal anodes. The resulting anodes, Na specifically, demonstrate promising potentials with mitigated dendritic growth and boosted plating/stripping stability ( 4 , 12 ), whereas modulation of sodiophilic nucleation sites has been recognized as one of the most underlying factors for navigating the initial Na nucleation behavior and subsequent growth.…”

Interfacial Protection Engineering of Sodium Nanoparticles toward Dendrite‐Free and Long‐Life Sodium Metal Battery

“…Due to the high theoretical specific capacity (1165 mAh g −1 ) and low standard electrode potential (−2.71 V vs the standard hydrogen electrode) of metallic sodium (Na) anode, sodium metal batteries (SMBs) are regarded as one of the most prospective secondary rechargeable energy‐storage equipment. [ 1 − 3 ] However, the practical application of Na anode is hindered by the following two aspects: 1) Owing to the high chemical reactivity, metallic Na easily reacts with electrolyte to form unstable solid electrolyte interface (SEI). [ 4,5 ] During the repeated plating/stripping processes, the huge volume variety of Na anode unavoidably causes the fracture of SEI layer; thus the newly exposed metallic Na will be consumed in constant contact with the electrolyte, finally leading to the depletion of electrolyte and poor Coulombic efficiency (CE).…”

Low‐Barrier, Dendrite‐Free, and Stable Na Plating/Stripping Enabled by Gradient Sodiophilic Carbon Skeleton

“…One may doubt that enlarging the specific surface area of current collectors to reduce the local current density can significantly lower the nucleation overpotential. [ 31,34–36 ] However, in our case, the specific surface area of CMFS (246.7 m 2 g –1 ) is obviously lower than that of CFS (489.2 m 2 g –1 ), as demonstrated in Figure S10 (Supporting Information). Hence, the optimized nucleation behavior of CMFS is mainly attributed to the improved disorder degree, the increased defect concentration and correspondingly the enhanced “sodiophilic” property of the CMFS electrode.…”