Abstract
Sodium (Na)-metal batteries have emerged as a promising alternative to lithium-metal batteries for next-generation batteries due to the low cost and natural abundance of Na. However, high reactivity of Na metal and uncontrollable growth of Na dendrites hinder the safe operation of Na-metal batteries. Several studies have been conducted to resolve those problems and regulating the initial Na nucleation is one of the promising methods for dendrite-free Na-metal anodes. Previous studies reveal that sodiophilic metal nanoparticles (Au, Ag, Sn, Sb, etc.) embedded 3D structures can induce the homogeneous initial Na nucleation and further guide uniform Na deposition. Herein, we newly develop a 3D nanostructured porous carbon particle containing carbon-shell-coated Fe nanoparticles (PC-CFe) as a highly reversible Na-metal host.1 PC-CFe delivers excellent cycling stability in asymmetric cells over 500 cycles with an average Coulombic efficiency of 99.6% at 10 mA cm-2 with 10 mAh cm-2 and in symmetric cells over 14,400 cycles at 60 mA cm-2. The role of carbon coating on Fe nanoparticles for enhanced sodiophilicity is also investigated by DFT calculations. Furthermore, the anode-free Na-metal batteries with a PC-CFe host and a high-loading Na3V2(PO)4 cathode shows an excellent capacity retention of 97% after 100 cycles at 1 mA cm-2. This work provides a novel approach toward the rational design of 3D hosts for next-generation Na-metal batteries.
References:
1. Lee, K.; Lee, Y. J.; Lee, M. J.; Han, J.; Lim, J.; Ryu, K.; Yoon, H.; Kim, B.-H.; Kim, B. J.; Lee, S. W. A 3D Hierarchical Host with Enhanced Sodiophilicity Enabling Anode-Free Sodium-Metal Batteries. Adv. Mater. 2022, 34, 2109767.