Exploring the supercapacitive and potentiodynamic characteristics of mycologically synthesized ruthenium sulphide nanoparticles

Transition metal dichalcogenides (TMDs) have recently attracted significant attention as electrode materials for electrochemical energy storage devices. In alignment with the growing emphasis on green approaches, we report, for the first time, the synthesis of ruthenium sulphide nanoparticles (RuS₂ NPs) using a fungal-mediated production method involving the endophytic fungus Fusarium oxysporum. The synthesis was carried out at neutral pH, ambient temperature, and pressure, aligning with the key principles of green synthesis. The optical, structural, morphological, and electrochemical properties of the RuS₂ NPs were investigated using various analytical techniques. Electrochemically active working electrodes (WEs) with enhanced anticorrosive properties, electrical conductivity, and hydrophobicity were fabricated by coating RuS₂ NPs onto carbon fabric-supported aluminium substrates, serving as current collectors. The WEs exhibited a specific capacitance (Cₛ) of 97.52 F g⁻¹ at a current density of 0.1 A g⁻¹ in 0.1 M H₂SO₄, with a capacitive retention of 90.5 % after 2000 charge-discharge cycles. Potentiodynamic polarization studies at 5 mV s⁻¹ , supported by scanning electron microscopy, revealed notable anticorrosive behaviour of the WEs, with controlled delamination at a rate of 0.16 mm/yr after 48 hours of immersion in 0.1 M H₂SO₄. These experimental results confirm the potential of Fusarium oxysporum as a promising fungal candidate for developing a novel, green, and sustainable method for synthesizing electrochemically active RuS₂ NPs for corrosion-resistant supercapacitor electrodes.