Trimetallic Hybrid Sulfides Embedded in Nitrogen-Doped Carbon Nanocubes as an Advanced Sodium-Ion Battery Anode

Metal sulfides are promising anodes for sodium-ion batteries because of their high theoretical capacities. However, they also suffer from the limitations of poor cycling stability and rate performance caused by volumetric strain. Here, trimetallic hybrid sulfide (Ni, Fe, Co)S-x nanocrystals embedded into nitrogen-doped carbon nanocubes are successfully obtained with abundant channels for ion diffusion, high specific surface area for a pseudocapacitive effect, and enough voids to buffer volumetric strain. As anode material for a sodium-ion battery, the hybrid sulfides exhibit highly reversible specific capacity, good rate capability, and cycling performance. Such mixed-metal sulfides with novel physical or chemical properties may also be extended to other emerging fields.