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. Staying on the ground: A stable sodium anode with ultra‐high specific capacity (1078 mAh g−1) is achieved by accommodating metallic sodium into a sodiophilic interphase based on oxygen‐functionalized carbon nanotube networks. The interphase renders the Na anode with a homogeneous nucleation process and a lateral plating behavior, which thermodynamically contrasts with regular vertical Na growth (dendrites).