Engineering copper doped MoS2 nanoflowers anchored on graphene oxide for ultra-stable sodium-ion storage

Sodium-ion batteries (SIBs) are critical for sustainable large-scale energy storage, yet their deployment is severely constrained by the intrinsic sluggish kinetics and structural fragility of high-capacity anodes. To address these bottlenecks, we propose a synergistic strategy integrating atomic orbital engineering with a macroscopic conductive network. A Cu-doped MoS 2 composite anchored on graphene oxide (Cu-MoS 2 /GO) was synthesized via a facile one-step hydrothermal method. In this architecture, the atomic-level Cu incorporation acts as an orbital modulator to intrinsically tune the d -band center of MoS 2 , optimizing the electronic configuration of Mo atoms and thereby weakening the energy barrier for Na⁺ adsorption/desorption. Simultaneously, the graphene oxide matrix constructs a robust 3D conductive skeleton, which not only facilitates electron transport and exposes abundant active sites but also effectively buffers the volume expansion. Benefiting from this low-barrier kinetic design and structural reinforcement, the Cu-MoS 2 /GO nanocomposite exhibits remarkable electrochemical performance. It delivers high reversible capacities of 493.8 and 446.9 mAh g −1 at 0.5 and 2.5 A g −1 , respectively, demonstrating excellent rate capability. Furthermore, it shows outstanding long-term cycling stability, retaining 377.0 mAh g −1 after 1000 cycles at 2 A g −1 . When assembled in a full cell with a Na 3 V 2 (PO 4 ) 3 cathode, it maintains 93.4 mAh g −1 after 200 cycles at 1 A g −1 . This work highlights the pivotal role of d -band center modulation in awakening the latent capabilities of conversion-type materials for advanced sodium-ion storage.