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 (Sb_1.6Bi_0.1Sn_0.1Mn_0.1Co_0.1Te₃, 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.