Facile synthesis of nanocrystalline high-entropy diboride powders by a simple sol-gel method and their performance in supercapacitor

A sol-gel method was employed for the synthesis of new High-entropy boride (HEB) powders, (Hf0.2Nb0.2Cr0.2Ta0.2Mo0.2)B2, with nanoscale. The as-synthesized powders were obtained at a relatively low temperature of 1650 degrees C, and had small average particle size of 62.09 nm. X-ray diffraction confirmed that the (Hf0.2Nb0.2Cr0.2Ta0.2Mo0.2)B2 powders were hexagonal single-phase without any oxide impurities. In particular, electrochemical performance of the (Hf0.2Nb0.2Cr0.2Ta0.2Mo0.2)B2 powders with multiphase and high-entropy single phase were investigated using a three-electrode system. The improved electrochemical performance of the HEB powders is realized, with 27% higher in specific capacitance compared to the powders with multiphase. The HEB powders electrode exhibits a high capacitance retention of 97.03% after 5000 cycles.

Automated summary

A new nanoscale high-entropy boride (Hf0.2Nb0.2Cr0.2Ta0.2Mo0.2)B2 was synthesized using the sol-gel method, with a low temperature of 1650 degrees C and an average particle size of 62.09 nm. X-ray diffraction confirmed its hexagonal single-phase structure without oxide impurities. The electrochemical performance of the HEB powders with multiphase and high-entropy single phase was studied, showing a 27% increase in specific capacitance compared to the multiphase powders. The HEB powders electrode exhibited a high capacitance retention of 97.03% after 5000 cycles.