3D uniform nitrogen-doped carbon skeleton for ultra-stable sodium metal anode

Sodium metal batteries are arousing extensive interest owing to their high energy density, low cost and wide resource. However, the practical development of sodium metal batteries is inherently plagued by the severe volume expansion and the dendrite growth of sodium metal anode during long cycles under high current density. Herein, a simple electrospinning method is applied to construct the uniformly nitrogen-doped porous carbon fiber skeleton and used as three-dimensional (3D) current collector for sodium metal anode, which has high specific surface area (1,098 m²/g) and strong binding to sodium metal. As a result, nitrogen-doped carbon fiber current collector shows a low sodium deposition overpotential and a highly stable cyclability for 3,500 h with a high coulombic effciency of 99.9% at 2 mA/cm² and 2 mAh/cm². Moreover, the full cells using carbon coated sodium vanadium phosphate as cathode and sodium pre-plated nitrogen-doped carbon fiber skeleton as hybrid anode can stably cycle for 300 times. These results illustrate an effective strategy to construct a 3D uniformly nitrogen-doped carbon skeleton based sodium metal hybrid anode without the formation of dendrites, which provide a prospect for further development and research of high performance sodium metal batteries.