3D mixed ion/electron-conducting scaffolds for stable sodium metal anodes

Abstract

Sodium (Na) metal batteries represent an optimal choice for the forthcoming generation of large-scale, cost-effective energy storage systems. However, Na metal anodes encounter several formidable challenges during the Na plating...

Unveiling the recent advances in micro-electrode materials and configurations for sodium-ion micro-batteries

“…Additionally, it can control the nucleation process of Na + to achieve more stable sodium deposition and growth. 88,117,118 The high specific surface area of the 3D porous framework can scatter the local current density and prevent the growth of mossy Na + /Na dendrites. 119 In the plating process, the distribution of Na + flux can be effectively controlled by adding a sodiophilic interface layer to the surface of the 3D framework.…”

Spatially Confined in Situ Formed Sodiophilic-Conductive Network for High-Performance Sodium Metal Batteries

“…Sodium (Na)-ion batteries (SIBs) face an energy density limitation (<200 Wh kg –1 ) − when utilizing hard carbon anodes. A Na metal anode with a low redox potential of −2.71 V offers a high theoretical specific capacity of 1166 mAh g –1 , promising a substantial improvement in the energy density of SIBs. − Nevertheless, challenges associated with Na metal anodes, such as uneven Na deposition, dendrite growth, and volume expansion, pose significant threats to the battery’s Coulombic efficiency (CE), reversible capacity, and cyclic stability. − …”

“…The huge volume expansion results in rupture of the SEI film, leading to disrupted Na + flux in the vicinity and consequently causing uneven Na deposition and dendritic Na growth. In contrast, 3D EC scaffolds with abundant pore structure have sufficient internal space and can serve as a host to buffer the volume deformation of deposited Na during cycling. ,, Regrettably, the intrinsic “sodiophobicity” of the scaffolds results in poor Na affinity, typically manifesting a high Na nucleation barrier, which adversely affects uniform Na nucleation and deposition. − Currently, the incorporation of Na-alloying metals like Sn, Sb, and Zn into the scaffolds has been reported to significantly enhance their affinity for Na (“sodiophilicity”). ,,− Nevertheless, the composite Na/scaffold anode still demonstrates an unsatisfactory cycle life owing to the blocked ion diffusion pathways within the EC scaffolds. , Sluggish ion diffusion kinetics may lead to the preferential Na + deposition on the top surface of the scaffolds rather than being densely filled, which undermines the structural benefits of the 3D scaffolds in regulating Na nucleation and spatial confinement, a situation exacerbated at high current densities. Therefore, constructing an ideal 3D scaffold with both Na affinity and robust ion transport capabilities is crucial for achieving a highly reversible dendrite-free Na metal anode.…”