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.