Al3+-Induced growth of α-Co(OH)2 nanoplates as high-capacity supercapacitors and water oxidation electrocatalysts

Abstract

In this paper, we report a metal ion-induced synthesis of α-Co(OH)₂ nanoplates as high-capacity supercapacitors and water oxidation electrocatalysts, which were synthesized by using metal ions of Al³⁺ as a structure-inducing agent through hydrothermal treatment. When used as electrode materials in supercapacitors, α-Co(OH)₂ nanoplates exhibit good capacitive properties of 709.1 F g⁻¹ at a current density of 1 A g⁻¹, maintaining 95.8% of the initial capacity at the current density of 5 A g⁻¹ after 1000 cycles. The α-Co(OH)₂ nanoplates can effectively oxidize water, showing excellent OER activity with a small overpotential of 348 mV at the current density of 10 mA cm⁻² and a large mass activity of 28.2 A g⁻¹, much higher than that of the β-Co(OH)₂ particle electrocatalyst (0.2 A g⁻¹). These results provide a new and facile approach to fabricating high-performance electrodes for supercapacitors and water oxidation electrocatalysts.