High-Entropy Sulfide Nanoarchitectures with Triple-Shelled Hollow Design for Durable Sodium-Ion Batteries

Metal sulfides are promising anode candidates for sodium-ion batteries (SIBs) due to their high theoretical capacities. However, their practical application is limited by significant volume extension and sluggish Na⁺ diffusion during cycling, which lead to rapid capacity degradation and poor long-term stability. In this work, we report the rational design of a hollow triple-shelled high-entropy sulfide (NaFeZnCoNiMn)₉S₈, synthesized through sequential templating method under hydrothermal conditions. Transmission electron microscopy confirms its well-defined three-shelled architecture. The inter-shell voids effectively buffer Na⁺ insertion/desertion-induced volume extension, while the tailored high-entropy matrix enhances electronic conductivity and accelerates Na⁺ transport. This synergistic design yields outstanding performance, including a high initial Coulombic efficiency (ICE) of 94.1% at 0.1 A g^-1, low charge-transfer resistance (0.32~2.54 Ω), fast Na⁺ diffusion efficiency (10^-8.5-10^-10.5 cm² s^-1), and reversible capacity of 582.6 mAh g^-1 after 1600 cycles at 1 A g^-1 with 91.2% capacity retention. These results demonstrate the potential of high-entropy, multi-shelled architectures as a robust platform for next-generation durable SIB anodes.