Flexible, free-standing and dendrite-free iron metal anodes enabled by MXene frameworks for aqueous Fe metal dual-ion batteries

Iron (Fe) metal batteries have been considered as one of the most promising power sources due to the low cost, abundant resources and safe characters. However, the dendrite growth of Fe metal anode during repeated cycling restricts its performance, which will bring about inner short-cut and many side reactions. To settle these problems, in this study, a new MXene/Fe heterostructure is designed as anode for Fe metal batteries. With the merits of flexibility, hydrophilicity and high electronic conductivity of MXene, the MXene/Fe heterostructure can effectively suppress the generation of Fe dendrite and accelerate the Fe plating/stripping kinetics. The detailed Fe growth mechanism on MXene is further probed. When utilized as anode for Fe metal dual ion batteries, stable cycling life and superior rate capability are obtained. These results may pave an alternative way for developing high performance Fe-based batteries.