Aluminum dendrite suppression by graphite coated anodes of Al-metal batteries

Rechargeable aluminum batteries (RABs) are regarded as a promising energy storage system considering the high safety, rich abundance, and high capacity of aluminum. One of the critical challenges for RABs is the dendrite growth of Al, which arouses significant stability and safety issues. In this work, we demonstrate that a graphite coating layer can effectively protect the Al anode against dendrite growth. The Al metal batteries with graphite-coated Al anodes display lower overpotential (43 mV) and better cycling stability (400 h) than those with bare Al. Based on spike-like voltage profiles, metallic Al is found to be preferentially plated on the graphite layer rather than the Al substrate. In addition, the rough graphite coating layer with abundant interspace further regulates the plating/stripping behavior and accommodates the volume change of the Al anode. The dendrite growth of Al is significantly suppressed by graphite coating, which also favors high-performance RABs with a graphite cathode. This study sheds light on the facile and efficient suppression of Al dendrite growth toward RABs. A graphite coating layer can effectively protect the Al anode against dendrite growth, exhibiting much enhanced cycle stability and reduced overpotential.