Sodium‐Ion Battery Full‐Cell Study with a Pseudocapacitive MoSe₂‐Porous N‐Doped Carbon Composite Anode and Intercalated Sodium Vanadium Fluorophosphate Cathode

Abstract Despite higher conductivity and larger d‐spacing (0.65 nm) of MoSe₂ compare to its analogous MoS₂ and higher theoretical capacity (∼422 mA h g⁻¹) compare to commercially available graphite, it experiences high volume expansion, sheets agglomeration during cycling, which limits their capacities and high rate application. Herein, we have shown interest in MoSe₂ materials as analogous to MoS₂ anode and grown MoSe₂ nanosheets on the nitrogen‐doped carbon followed by covered with reduced graphene oxides sheets (NC@MoSe₂@rGO) composite through a simple solvothermal synthesis followed by annealing treatment. The porous NC compound could bring several advantages like, it can reserve a sufficient amount of electrolyte for easy access of Na‐ion diffusion. Increasing the conductivity by introducing the doping of nitrogen on the NC structure and simultaneously rGO can reduce the volume expansion of MoSe₂ during the cyclic performance. Ex‐situ XANES and XPS technique explored the sodiation mechanism of the NC@MoSe₂@rGO composite. It has been found the irreversible conversion of MoSe₂ after 1^st cycle by converting the discharged products of Mo and Na₂Se. The NC@MoSe₂@rGO anode is connected with electrolyte and a high potential Na₃V₂O₂(PO₄)₂F (NVOPF) to acquire potential applications′ approval cathode material. The full‐cell delivers a voltage of operation at 2.1 V with high specific capacity of ∼176 mA h g⁻¹ (current rate of 0.05 A g⁻¹) with an energy density of ∼369.6 W h/kg _anode at 20 °C.