Antimony Telluride as Bifunctional Host Material for Dendrite-Free Sodium Metal Batteries.

The development of the sodium metal anode is hampered by uncontrolled Na dendrite growth and unstable solid electrolyte interface (SEI). Herein, SbTe nanosheets are anchored into the fibers of carbon cloth (CC) to construct SbTe@CC material as Na metal host for sodium metal batteries (SMBs). The alloying product of NaSb with strong sodiophilicity serves as a nucleation seed to induce homogeneous Na deposition and boost the formation of a dendrite-free Na metal anode. Meanwhile, the conversion product of NaTe covers the surface of Na metal to form a robust SEI film. Low current density, uniform Na ionic flux, and suppressed volume expansion can be guaranteed by three-dimensional carbon fibers. Therefore, a Na@SbTe@CC electrode contributes ultrastable cyclic performance for over 1600 h with a low overpotential of 30.5 mV. The assembled Na metal full batteries deliver a high initial energy density of 307.3 Wh kg and superior cycling stability with an ultralong lifespan of over 2000 cycles.