Immobilizing single atom on high-entropy oxides as separator regulators for catalyzing low-temperature lithium-sulfur battery

Abstract

The commercialization of lithium-sulfur batteries suffers from severe polysulfide shuttling, the sluggish kinetics of sulfur redox reaction and large desolvation barrier. Herein, an atom-dispersed Fe immobilized on high-entropy oxides (Cu-Zn-Al-Ce-ZrO) (SA-Fe/HEO@NC) is proposed via electron delocalization engineering, which serves as an efficient separator regulator for catalyzing sulfur cascade redox reactions with enhanced desolvation kinetics This design leverages electron delocalization engineering to enhance sulfur cascade redox reactions and desolvation kinetics, as confirmed by theoretical simulations and comprehensive electrochemical characterizations, including time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and in-situ Raman spectroscopy. Consequently, the cell with SA-Fe/HEO@NC modified separator displays final capacity of 1035 mAh g⁻¹ at 0.2 C after 100 cycles, and stabilizes for 4.1 mAh cm⁻² when increasing areal loading to ∼6 mg cm⁻² at 0.1 C after 200 cycles. Under 0 °C, an outstanding specific capacity of 751 mAh g⁻¹ with the high capacity-retention of 78.3 % after 100 cycles is still achieved at 1 C, verifying the feasibility of integrating single atom catalyst on high-entropy compounds for rapid conversion kinetics.