In-situ assembly of 3D VS2/Reduced 2 /Reduced graphene oxide with superior lithium ion storage performance: The role of heterojunction

VS2 2 is a potential anode material for lithium-ion batteries (LIBs) due to its advantageous properties. Herein, a novel three-dimensional (3D) VS2/reduced 2 /reduced graphene oxide (rGO) heterostructure (VS2-rGO) 2-rGO) was fabricated by in-situ assembly of caterpillar-like VS2 2 nanosheets on rGO. This 3D VS2-rGO 2-rGO with a well-defined heterojunction interface is engineered to mitigate the volumetric expansion of VS2 2 during Li + intercalation/deintercalation cycles. This optimized design promotes enhanced conductivity across the heterojunction, facilitating efficient electron and ion transport. The VS2-rGO 2-rGO electrode shows higher reversible capacity and better rate performance (644.02 mA h g- 1 at 0.1 A g- 1 after 140 cycles, 526.66 mA h g- 1 at 2 A g- 1 ) as compared to the pure VS2 2 electrode (433.69 mA h g- 1 at 0.1 A g- 1 after 140 cycles, 63.91 mA h g- 1 at 2 A g-- 1 ). Ex-situ XRD analysis suggests that the Li + storage mechanism in the VS2-rGO 2-rGO electrode involves the initial intercalation, followed by intercalation and conversion. The lower Li + diffusion barrier within the VS2-rGO 2-rGO heterojunction (0.183 eV) compared to the VS2 2 layers (0.225 eV), as predicted by first-principles calculations, resulting the enhanced Li + transport kinetics and improved cycling performance of the VS2-rGO 2-rGO electrode material. This work offers novel perspectives for the influence of heterojunctions on LIBs.