Constructing Borate-Doped 3D Flower-Like α-Nickel Hydroxide with High Capacitive Performance

Easily obtainable and low-cost electrodes are highly desirable for the application of supercapacitors. Here, borate-doped three-dimensional (3D) hierarchical flower-like α-nickel hydroxide (B@NOH) with an optimized pore structure was fabricated via a facile solid-state method without any solvent usage. Effects of the reaction time were investigated, and structural characterizations confirmed the formation of the α-Ni(OH)₂ structure and borate doping. The electrode synthesized in 2 h (B@NOH-2) had the best performance with a specific capacitance of 403.6 C/g (1009 F/g) at 1 A/g in a three-electrode system. The reaction time was critical to finding the optimum performance, and it affected not only the morphology of α-Ni(OH)₂ but also the porosity features. Here, for the first time, we demonstrate the use of borate-doped 3D α-Ni(OH)₂ as a low-cost supercapacitor electrode, and these results prove the potential of borate doping as a strategy to enhance the electrochemical performance of other metal hydroxide electrodes.