RETRACTED: Efficient commercial-like fast charging supercapacitor device utilizing N,S- doped carbon nanosheets derived from a Cu 2 Fe(CN) 6 /Cu 7 S 4 /Cu 1.8 S/carbon nanocomposite via a layered nanohybrid precursor

Abstract

The modern world demands more efficient energy storage devices that are not only smaller and lighter but also capable of storing greater amounts of energy. Among these devices, batteries and supercapacitors (SCs) play crucial roles. However, a persistent challenge with real-world commercial carbon-based SCs is their relatively low energy density and capacity. To address this, researchers have explored strategies such as doping carbon materials with heteroatoms and hybridizing or combining carbon with certain metal compounds. In this study, a novel Cu2Fe(CN)6/Cu7S4/Cu1.8S/N,S-doped carbon nanocomposite was developed using a copper hydroxide ferrocyanide nanohybrid as a precursor. Through an acid etching process, the Cu2Fe(CN)6/Cu7S4 and Cu1.8S phases were selectively removed, resulting in Cu1.8S/N,S-doped carbon and N,S-doped carbon nanosheets. This approach sheds light on the critical role of nanocomposite components in achieving enhanced capacity. The specific capacitance (Cs) values for the parent Cu2Fe(CN)6/Cu7S4/Cu1.8S/N,S-doped carbon nanocomposite, the intermediate Cu1.8S/N,S-doped carbon nanocomposite, and the final N,S-doped carbon material were 1000.4, 887.9, and 392.2 F/g, respectively, when utilized as the active material in the three-electrode system. Moreover, a viable commercial-like symmetric SC device was created using N,S-doped carbon nanosheets, designed for rapid charging in practical applications. The device demonstrated a high capacitance value of 32.7 F/g, an energy density of 40.9 Wh/kg, and a power density of 1500 W/kg using a regular slow charge-discharge approach. Furthermore, despite its remarkably fast 2-second charge time, the device maintains a capacitance retention of approximately 94% after 1000 cycles at an operating voltage of 2.8 V.