Suppressing Al dendrite growth towards a long-life Al-metal battery

Great progress has been made in the development of cathode materials for Al-metal batteries . However, the in-depth study of Al anodes, especially the battery instability caused by Al dendrite growth, has not received much attention. In this work, we have identified the in-situ formation of Al dendrite growth, which is proved to bottleneck the practical use of Al-metal batteries. The dendrite formation severely affects battery performance, such as voltage and efficiency fluctuations, unstable cycling, etc. To further demonstrate the detailed growing process of dendrites, we make a comprehensive investigation into the interfacial chemistry of Al anode. We have found that the naturally formed Al 2 O 3 surface film is dissolved in the ionic liquid electrolyte during Al plating, accompanied by the formation of solid-electrolyte interphase containing Al-Cl and Al-O like species on the anode surface before dendrite growth. To suppress this dendrite growth, we propose the use of porous Al, which provides a homogeneous ion flux and decreases the local current density. As a result, the porous anode maintains stable cycling over a wide range of current densities and areal capacities. The Al-graphite battery shows stable cycling up to 18000 times without capacity decay. This work suggests the significance of suppressing dendrite growth for the real applications and commercialization of Al-metal batteries and will draw attention to the battery design from the anode side .