Organic−Inorganic VEG-VO@MoOSe Electrode for Enhanced Ion Storage in a Hybrid Supercapacitor and Sn-Ion Capacitor

Designing a single high-performance electrode compatible with both hybrid supercapacitors and metal-ion capacitors remains a significant challenge. Here, we present an organic−inorganic hybrid electrode, VEG-VO@MoOSe (VMS), synthesized via a solvothermal approach by in situ coupling of vanadyl ethylene glycolate-assisted vanadium oxide (VEG-VO) with Mo and Se precursors. This integration induces the formation of MoOSe over MoSe2, generating lattice mismatches, rich defect sites, and expanded interlayer spacing. These structural features increase active sites and modulate the electronic environment, collectively promoting efficient ion diffusion and charge storage. The incorporation of vanadium oxide (VO2) extends pseudocapacitive behavior within the electric double-layer (EDL) framework, enabling a hybrid charge storage mechanism combining capacitive, pseudocapacitive, and faradaic processes. The VMS2 electrode exhibits a high specific capacitance of 589.7 F g−1 at 1 A g−1, significantly surpassing that of MoSe2. The VMS2//MnO2 hybrid supercapacitor achieves a power density of 7.99 kW kg−1 at an energy density of 48.33 Wh kg−1, while a Sn-ion capacitor (Sn//VMS2/GF) delivers a specific capacity of 154.1 mAh g−1, with a peak energy density of 141.8 Wh kg−1, retaining 82.4% capacity over 4000 cycles. These results highlight VMS2 as a multifunctional electrode that bridges the EDL and pseudocapacitive storage modes for advanced hybrid energy devices.