posted on 2023-11-13, 18:07authored byEmily
R. Cooper, Ming Li, Qingbing Xia, Ian Gentle, Ruth Knibbe
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 ZnF2-rich interphase. This study offers valuable insight into
selecting current collectors and engineering the interfacial chemistry
to improve the performance of anode-free NMBs.