Sodiophilic Decoration of a Three-Dimensional Conductive Scaffold toward a Stable Na Metal Anode

Although Na metal is regarded as one of the most promising anode materials for Na-based batteries because of its high specific capacity (1166 mA h g(-1)) and low redox potential (-2.71 V versus the standard hydrogen electrode), many issues, such as dendrite-induced safety concerns, low efficiency, and poor cyclability, severely impede its practical application. Herein, to alleviate the abovementioned problems, a nitrogen-doped graphene-modified three dimensional nickel foam framework was constructed as the host material for Na plating. The sodiophilic Ncontaining functional groups in the graphene structure can effectively reduce the nucleation overpotential of Na, guide the homogeneous Na-ion flux, regularize the electric field distribution, and eventually inhibit Na dendrite formation. As a result, the Na composite metal anode can be cycled reversibly free from dendrite obsessions with a high Coulombic efficiency exceeding 99% at 0.5 mA cm(-2) , 1 mA h cm(-2) for at least 800 cycles and 99% at 1 mA cm(-2) , 2 mA h cm(-2) for at least 200 cycles. Based on this anode, a symmetric cell with ultralow voltage polarization (similar to 11 mV) and long-running lifespan (1000 h at 1 mA cm(-2) for 1 mA h cm(-2)) can be realized. Furthermore, a full cell coupled with a Na3V2 (PO4)(3) cathode delivers a prolonged lifespan (250 cycles at 2 C) and excellent rate performances, demonstrating a facile but effective avenue to achieve Na metal anode stabilization.