A Sodiophilic Interphase-Mediated, Dendrite-Free Anode with Ultrahigh Specific Capacity for Sodium-Metal Batteries

Despite efforts to stabilize sodium metal anodes and prevent dendrite formation, achieving long cycle life with high areal capacities remains difficult owing to a combination of complex failure modes that involve retardant uneven sodium nucleation and subsequent dendrite formation. Now, a sodiophilic interphase based on oxygen-functionalized carbon nanotube networks is presented, which concurrently facilitates a homogeneous sodium nucleation and a dendrite-free, lateral growth behavior upon recurring sodium plating/stripping processes. This sodiophilic interphase renders sodium anodes with an ultrahigh capacity of 1078 mAh g^-1 (areal capacity of 10 mAh cm^-2 ), approaching the theoretical capacity of 1166 mAh g^-1 of pure sodium, as well as a long cycle life up to 3000 cycles. Implementation of this anode allows for the construction of a sodium-air battery with largely enhanced cycling performance owing to the oxygen functionalization-mediated, dendrite-free sodium morphology.