High-Entropy Telluride as Multifunctional Host Material with Synergistic Conversion-Alloying Chemistry of Dendrite-Free Sodium Metal Anode for Quasi-Solid-State Batteries

The development of sodium metal anodes is hampered by uncontrolled dendritic growth, severe volume variation, and a fragile solid electrolyte interface (SEI). Herein, a high-entropy telluride (Sb1.6Bi0.1Sn0.1Mn0.1Co0.1Te3, HET) anchored onto carbon cloth served as host material (HET@CC) of a Na metal anode for quasi-solid-state batteries. High-entropy composition provides abundant sites for favorable interfacial kinetics, dendrite-free Na metal deposition, and enhanced structure stability. The yielded multiple alloying phases (Na3Sb, Na3Bi, and Na15Sn4) with great sodiophilicity significantly reduce the Na nucleation barrier, the conversion products (Co and Mn) serve as electron-conducting networks to enable uniform charge distribution, and Na2Te contributes to forming a robust SEI. Consequently, Na@HET@CC achieves high Coulombic efficiency exceeding 99.5% over 2000 h in an asymmetric cell and ultralong lifespans of 2000 h with a low overpotential of 5.8 mV. The quasi-solid-state Na metal full batteries deliver a high initial energy density of 367.4 Wh·kg–1 and superior cyclic stability with an ultralong lifetime over 1500 cycles.