Mediated by Polymer Intercalation Differential: Molecule Steric Hindrance Triggers 1T‐2H MoS ₂ Heterostructures for Ultrafast and Ultrastable Li ⁺ /Na ⁺ Storage

The organic molecule of phytic acid is innovatively utilized to block the edges of partial MoS 2 with steric effect to achieve differential intercalation of polypyrrole. After annealing, the intercalated MoS 2 nanosheet retains the 1T phase with a large spacing of 0.98 nm, while the unintercalated regions transform into the 2H phase with a small spacing (0.62 nm), thus forming a 1T‐2H MoS 2 heterostructure. This structure integrates the high electrochemical activity of the 1T phase with the excellent stability of the 2H phase. Furthermore, MoS 2 nanosheets are anchored by nitrogen‐doped carbon (NC) nanotubes and coated with a N/P co‐doped carbon (NPC) protective layer, forming a unique sandwich hierarchical structure (NC@T/H–MoS 2 @NPC). The synergistic effect of the 1T‐2H MoS 2 heterostructure and the unique hierarchical structure enhances ion diffusion kinetics and structural integrity. This electrode demonstrates remarkable cycling life, with 8 000 cycles at 10 A g −1 in Li‐ion batteries and 15 000 cycles at 5 A g −1 in Na‐ion batteries. The 1T and 2H phases exhibit different storage Na + /Li + behaviors under ex situ X‐ray diffraction tests. The density functional theory results reveal the heterostructure and NC layer modulate the Fermi level, reducing Li + /Na + migration energy barrier and optimizing energy storage.