Electrochemical investigation of uncapped AgBiS2 (schapbachite) synthesized using in situ melts of xanthate precursors

Abstract

In this study, a facile and potentially scalable synthesis of AgBiS₂ (schapbachite) using melts of metal xanthates is presented; AgBiS₂ is both a significant mineral and a technologically important material. This ternary material was synthesized by a novel and low-cost solventless route using simple ethyl xanthate complexes of silver and bismuth. p-XRD analysis indicates that the synthesized ternary material is highly crystalline and belongs to the cubic phase (schapbachite). The electrochemical properties of the material were tested; the potential of the synthesized material for application in charge storage shows a high specific capacitance of 460 F g⁻¹ at 2 mV s⁻¹. A capacitance retention of 83% with a 100% coulombic efficiency was observed after 3000 cycles. The charge storage potential, analysed by fabricating actual symmetrical devices, shows a specific capacitance of 14 F g⁻¹ at 2 mV s⁻¹. An energy density of 26 W h kg⁻¹ and a power density of 3.6 kW kg⁻¹ were observed. Besides, the potential for the oxygen evolution reaction was also studied. An overpotential of 414 mV and a Tafel slope of 134 mV dec⁻¹ were obtained for water oxidation. The fabrication of an electrolyzer cell using the synthesized material as the cathode indicates that a current of 10 mA cm⁻² can be achieved at a potential of 1.63 V.