Facilitating Sodium Nucleation in Anode-Free Sodium Batteries

Abstract

Sodium metal batteries (NMBs) have attracted significant attention as next-generation, high energy density battery technologies. However, NMBs are disadvantaged by the excessive Na metal used as the anode, which decreases energy density and safety. So-called anode-free NMBs, where the anode is electrochemically generated during charging, are a promising solution. However, such batteries are still prone to dendrite growth and capacity fade. In this work, we computationally and experimentally screen a range of metals, including Zn, Cu, and α-brass, as current collectors for anode-free NMBs. Our results show that Zn was the best performing current collector material, inducing small nucleation overpotentials of −16.5 mV and increasing cycling stability up to 200 cycles with an average Coulombic efficiency of 98.9%. We propose this high performance is due to high lattice compatibility between Na and Zn as well as the formation of a favorable ZnF 2 -rich interphase. This study offers valuable insight into selecting current collectors and engineering the interfacial chemistry to improve the performance of anode-free NMBs.

Recent Progress and Prospects on Sodium-Ion Battery and All-Solid-State Sodium Battery: A Promising Choice of Future Batteries for Energy Storage

“…The fundamental driving force for metal nucleation is the change in Gibbs free energy. Minimizing the Gibbs energy barrier can improve metal nucleation in anode-free batteries, thereby enhancing the overall battery performance . Haocheng Yuan et al studied an efficient sodium plating technology induced by an in-plane isotropic separator.…”

“…Stages of sodium nucleus formation on a current collector (from left to right). Reproduced with permission from ref . Copyright 2023 American Chemical Society.…”