Improving the specific capacity of nickel hydroxide nanocrystals via yttrium doping for application in hybrid supercapacitors

Abstract

Herein, Y-doped Ni(OH)₂ composites were successfully fabricated via a simple hydrothermal process. The specific surface areas were significantly improved when Y³⁺ ions were incorporated into the Ni hydroxide lattice. The Y-doped Ni(OH)₂ electrode exhibited the remarkable specific capacity of 735.46 C g⁻¹ at 1.5 A g⁻¹ and ultrahigh rate performance with 71.36% capacity retention at 20 A g⁻¹. The optimum Y-doped Ni(OH)₂ electrodes were further evaluated for application in an asymmetric supercapacitor, demonstrating the maximum energy density of 55.49 W h kg⁻¹ at the power density of 843.31 W kg⁻¹ as well as satisfying cycling performance with 85.8% retention after 7000 cycles.