Suppressing zinc dendrite growth in aqueous battery via Zn–Al alloying with spatially confined zinc reservoirs

Rechargeable aqueous zinc-ion batteries are attractive candidates as energy storage technology, but the uncontrollable Zn dendrite formation and low stripping/plating coulombic efficiency when using bare Zn metal foil as anode have severely limit the battery reliability and energy density. Thus, to develop a more robust ZIB anode with lower extent of dendrite growth, Zn–Al alloy is proposed in this work. The passivating Al2O3 shell formed on the Al phase can provide two key functions; (1) selective electrochemical stripping of Zn due to electrochemically inert Al2O3, and (2) guiding the electrodeposition of Zn on the available Zn sites. The as-prepared Zn–Al alloy anode is able to outperform the bare Zn anode as bare Zn anode shows signs of short circuit after cycling. When paired with V6O13 cathode, the Zn–Al//V6O13 cell delivers enhanced rate performance and a nearly 95% capacity retention after 1000 cycles at 3 A g−1, with a specific capacity of 280 mA h g−1. The strategy demonstrated that Zn–Al alloy is suitable for aqueous zinc-ion batteries due to its low corrosion rate, low dendrite formation, low corrosion current, and high capacity retention.