Anode-free Na metal batteries developed by nearly fully reversible Na plating on the Zn surface.

The anode-free battery architecture has recently emerged as a promising platform for lithium and sodium metal batteries as it not only offers the highest possible energy density, but also eliminates the need for handling hazardous metal electrodes during cell manufacturing. However, such batteries usually suffer from much faster capacity decay and are much more sensitive to even trace levels of irreversible side reactions on the anode, especially for the more reactive Na metal. This work systematically investigates electrochemical interfaces for Na plating and stripping and describes the use of the Zn surface to develop nearly fully reversible Na anodes with 1.