Self‐Assembling of Conductive Interlayer‐Expanded WS2 Nanosheets into 3D Hollow Hierarchical Microflower Bud Hybrids for Fast and Stable Sodium Storage

Abstract Transition‐metal dichalcogenides have emerged as promising anodes of sodium ion batteries (SIBs). Their practical SIB application calls for an easy‐to‐handle synthetic technique capable of fabricating favorable properties with high conductivity and stable structure. Here, a solvothermal strategy is reported for bottom‐up self‐assembling of nanoflowers' building block, i.e., conductive interlayer‐expanded 2D WS 2 nanosheets thanks to in situ interlayer modification by nitrogen‐doped carbon matrix, into 3D hollow microflower bud‐like hybrids (H‐WS 2 @NC). The 3D nano/microhierarchical hollow structures are constructed by conductive interlayer‐expanded WS 2 nanosheets' building blocks, providing abundant channels facilitating mass transport/electrons transfer, robust protection layer to avoid the direct contact between WS 2 nanosheets and electrolyte, sufficient inner space for accommodating volume variation, and decreased ions diffusion energy barrier for accelerating electrochemical kinetics, as revealed by density functional theory calculations. As such, the 3D H‐WS 2 @NC hybrids exhibit quite attractive sodium storage performance with high reversible capacity, superior rate capability, and impressively long cycling life. The 3D H‐WS 2 @NC is further verified as anode of sodium‐ion full cell pairing with Na 3 V 2 (PO4) 3 /rGO cathode, delivering a stable reversible capacity of 296 mAh g −1 at 0.5 A g −1 with high energy density of 128 Wh kg −1 total at a power density of 386 W kg −1 total .