Valence‐Adaptable Ni/Co Catalysis for High‐Rate Sodium–Sulfur Batteries with Wide‐Temperature Operation from −20 to 50 °C

Abstract

Abstract To address the challenges posed by diverse global climates, the development of wide‐temperature‐operable batteries is essential. Here Ti 3 C 2 O x is used as inner sheets to support the growth of NiCo‐LDH wrinkles, forming a unique cavity‐structured sulfur host. The resulting cathode demonstrates state‐of‐the‐art high‐rate performance, delivering a remarkable capacity of 1130.7 mAh g −1 at 5 A g −1 over 1200 cycles. It also exhibits outstanding wide‐temperature operation, maintaining capacities of 1150.0 mAh g −1 at 50 °C (5 A g −1 ) and 969.1 mAh g −1 at −20 °C (1 A g −1 ) after 600 cycles. This exceptional performance across temperatures is attributed to the reversible redox behavior of the Ni 2.32+ ↔ Ni 2.54+ and Co 2.46+ ↔ Co 2.84+ redox couples. These transition metals from NiCo‐LDH act as electron donors during discharge (from S 8 to Na 2 S) and as electron acceptors during charge (from Na 2 S to S 8 ), thereby accelerating electron transfer and enabling efficient polysulfide conversion even at low temperatures. Furthermore, adsorption experiments and density functional theory (DFT) calculations reveal that NiCo‐LDH preferentially adsorbs short‐chain polysulfides (Na 2 S/Na 2 S 2 ), while Ti 3 C 2 O x exhibits stronger affinity for long‐chain polysulfides (Na 2 S 4 /Na 2 S 6 ). This synergistic adsorption behavior enhances polysulfide retention and mitigates the shuttle effect, contributing to excellent performance stability even at high temperatures.