Optimizing the supercapacitive performance of MoS₂ by multivalent tungsten ion doping

This study examined the effect of tungsten doping on the structural and electrochemical performance of molybdenum disulfide (MoS₂) in symmetric supercapacitor devices. MoS₂ nanoflowers with different W contents (0-1%) were synthesized by a hydrothermal method and characterized using XRD, Raman, PL, EPR, SEM, and BET analysis. Tungsten incorporation induced lattice distortions, sulfur vacancies, and enhanced defect-assisted charge transport, while retaining the layered morphology. Electrochemical measurements revealed a combination of electric double-layer and pseudocapacitive behavior with the MoS₂:W0.7 electrode material delivering the highest performance. This device achieved a specific capacitance of 848 F g^-1 at 10 mV s^-1, an energy density of 117.8 Wh kg^-1, a power density of 2121 W kg^-1, and excellent cycling stability, retaining 97% of its capacitance. The results demonstrate that W doping introduces additional electroactive sites and improves conductivity, highlighting a simple strategy to enhance the energy-storage capability of MoS₂-based materials for supercapacitor applications.