Synthesis and capacitive performance of ZrB2 and its composites as supercapacitor electrodes

Abstract

The possibility of using zirconium diboride (ZrB2) as an electrode for supercapacitor devices has yet to be extensively studied, even though there is a wealth of literature on various properties of ZrB2. In this study, ZrB2 and its composites were directly assembled as electrode materials into symmetric and asymmetric supercapacitor devices. ZrB2 powders were synthesized by using mechanical activation assisted direct synthesis route followed by a purification step. Powders were illustrated with precise size tuning in the 200-500 nm range. Then, the ZrB2-based composite materials containing silicon carbide (SiC) particles were prepared by using a mechanical alloying process. Microstructural and thermal analyses of the particles were carried out and optimum powders were selected for the measurements of electrochemical performance. Both symmetric and asymmetric supercapacitors exhibited excellent cycling performances: After 50 cycles, the devices display 79 and 69% capacitance retention as well as 108 and 123% coulombic efficiency at 0.1 A g-1, respectively for the symmetric ZrB2/ZrB2 and asymmetric ZrB2/ZrB2-15 wt%SiC supercapacitors. The symmetric supercapacitor exhibited higher performance than asymmetric one with a specific energy and power density of 4.2 W h kg-1 and 150 W kg-1, respectively. As a result, high energy density and high capacity values, and excellent cycling performances are obtained, meaning that ZrB2 and its composites are promising materials for energy storage purposes.