Carbon‐Insertion‐Engineered WS ₂ Hierarchical Heterostructure Enabling Superior Sodium‐Ion Storage

ABSTRACT Tungsten disulfide (WS 2 ) is considered a promising anode material for sodium‐ion batteries (SIBs). However, its practical application is hindered by poor electrical conductivity, large volume changes during cycling, and sluggish ion diffusion kinetics, which lead to unsatisfactory electrochemical performance. To address these challenges, we develop a sustainable WS 2 ‐based anode through the strategic intercalation of oxygen‐doped carbon layers (OC) between WS 2 sheets. This strategy constructs a three‐dimensional (3D) nanoarchitecture featuring expanded interlayers and overlapped heterointerfaces, where single‐layer WS 2 and carbon are alternately stacked. The resulting 2H‐WS 2 @OC composite offers enhanced structural stability, more active sites, and accelerated charge transport for both electrons and ions. Consequently, the 2H‐WS 2 @OC‐16 anode for SIBs delivers a high rate capacity of 125.5 mAh g −1 at 8 A g −1 and retains 84.0% of its capacity after 200 cycles at 1 A g −1 , significantly outperforming pristine 1T‐WS 2 . Furthermore, the Na 3 V 2 (PO 4 ) 3 /C//2H‐WS 2 @OC‐16 full cell for SIBs achieves a reversible capacity of 235.5 mAh g −1 at 50 mA g −1 and maintains 109.7 mAh g −1 at 1 A g −1 after 200 cycles. Meanwhile, we also verify the effectiveness of our 2H‐WS 2 @OC in potassium‐ion batteries. It is believed that our approach of optimizing the structure of layered materials by controlling the carbon intercalation process brings a new inspiration to accurately regulate the electrodes for battery applications.