Structural engineering of MoSe₂ via interfacial effect and phosphorus doping incorporation for high energy density sodium ion storage

Sodium-ion batteries (SIBs) are gaining increasing attention for the development of electrode materials due to their potential to alleviate the safety concerns and resource scarcity associated with lithium-ion batteries (LIBs). Based on this, the present work, built upon the electrospinning preparation of hollow carbon nanofibers (HCNFs), facilitated the in-situ growth of MoSe₂ nanosheets on their surface. Subsequently, an in-situ phosphorization treatment was applied, resulting in phosphorus-doped MoSe₂ (P-MoSe₂)@HCNFs. The dual-channel inner layer of HCNFs in this structure promotes ion transport and directly interfaces with MoSe₂, leading to abundant interfacial effects. The outer layer of MoSe₂ serves as the primary redox-active unit for sodium ions, retaining numerous active sites. P doping further optimizes the overall electronic structure of the material. P-MoSe₂@HCNFs serves as the anode material in SIBs, demonstrating exceptional reversible specific capacity and rate capabilities. It achieves a remarkable 479.17 mAh g⁻¹ over 500 cycles at 1 A g⁻¹ and 397.01 mAh g⁻¹ over 950 cycles at 10 A g⁻¹, showcasing its outstanding performance. These values significantly surpass those of MoSe₂@HCNFs and pure MoSe₂, validating the pronounced advantages of the structure we have constructed. Leveraging the outstanding kinetic performance of P-MoSe₂@HCNFs, when assembled with Na₃V₂(PO₄)₃ as the cathode, the full cell exhibits remarkable sodium storage capability. It achieves a high energy density of up to 194.75 Wh kg⁻¹, providing a feasible solution for the application of transition metal selenides in sodium-ion battery systems.