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 MoS₂ with steric effect to achieve differential intercalation of polypyrrole. After annealing, the intercalated MoS₂ 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 MoS₂ heterostructure. This structure integrates the high electrochemical activity of the 1T phase with the excellent stability of the 2H phase. Furthermore, MoS₂ 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-MoS₂@NPC). The synergistic effect of the 1T-2H MoS₂ 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.