Preparation of (VNbTaZrHf)C high-entropy carbide nanoparticles via electro-deoxidation in molten salt and their supercapacitive behaviour
Yang Yu, Buxin Chen, Junyu Chen, Liwen Hu, Meilong Hu
Abstract
Nanoscale (VNbTaZrHf)C high-entropy carbide (HEC) powders were prepared by electrochemical reduction in CaCl2 molten salt at 1173 K using the mixture of the individual metal oxides and graphite. The product of (VNbTaZrHf)C HEC powders with a face-centred cubic (fcc) structure can be prepared by this method and the particle size is below 100 nm. The moderate processing temperature is beneficial to prevent the in-situ sintering growth of the ultra-high melting HEC particles. The supercapacitive behaviour of the prepared HEC is evaluated in a three-terminal electrochemical cell with the intention of exploring the potential of supercapacitor applications. The specific capacitance of 50 F/g is achieved at a scan rate of 10–100 mV/s in 1 M KOH, and the capacity retention is 89% after 2500 full cycles. This excellent supercapacitive behaviour makes (VNbTaZrHf)C HEC a promising candidate for supercapacitor applications due to its high entropy effect and nanoscale structure.