Zinc–air batteries: are they ready for prime time?

Zn–air batteries are under revival. They have large theoretical energy density and potentially very low manufacturing cost compared to the existing Li-ion technology. However, their full potential has not been fulfilled due to challenges associated with air cathodes and Zn anodes. In this minireview, we present the current status and technical hurdles of Zn–air batteries and discuss the possible direction of their future improvements. We show that in contrast to tremendous efforts on the design and development of efficient cathode electrocatalysts over recent years, the pursuit of stable and cyclable Zn anodes is equally important but receives far less attention than deserved. We therefore call for a shift of future research focus from cathode electrocatalysts to Zn anodes in order to make this century old technology a truly commercial reality.