Heteroelement Y-doped α-Ni(OH)2 nanosheets with excellent pseudocapacitive performance

Abstract

Doping is an efficient method to promote the electronic conductivity and improve the capacitive performance of electrodes for further energy conversion. Herein, by doping heteroelement metal ions, an ultrathin Y (yttrium)-doped α-Ni(OH)₂ nanosheet electrode with a large surface area and hierarchical porous structure is fabricated via a facile approach. The Y-doped α-Ni(OH)₂ nanosheets exhibit a high specific capacitance of 1860 F g⁻¹ at a current density of 1 A g⁻¹ mainly due to the increased electronic conductivity of the increased Ni³⁺ species, as evidenced by density functional theory calculations. As a result, the asymmetric supercapacitor device based on the Y-doped α-Ni(OH)₂ nanosheet electrode demonstrates both a remarkably high energy density (58.4 W h kg⁻¹) and power density (754.56 W kg⁻¹).