Towards High Capacitive Performance of Chemically Deposited β-Ni(OH)2 Nanolamellae Electrode Films.

Abstract

Nickel hydroxide β-Ni(OH)2 nanolamellae with high aspect ratios were grown via chemical bath deposition (CBD) on both smooth and textured nickel foil. Depending on bath composition and/or the presence of an additive, thin foam-like nanolamellae to stacked lamellae were obtained. The used CBD method is highly cost-effective, as it is faster and requires less chemicals than typical hydrothermal methods, and it is readily implementable for large-scale production. The influence of surface texture on the final morphology and its effect on capacitive performance was investigated. Herein, we show how subtle changes in the concentration can drastically influence the morphology, which, in turn, drastically impacts the supercapacitive performance of the electrode. Also, the use of a textured surface significantly impacts the morphology, with vastly better cycling performance than samples made on a relatively smooth substrate. The measured specific capacitance values of the best sample were 1961 Fg-1 at 5 mVs-1 and 1998 Fg-1 at 1 Ag-1 under potentiostatic and galvanostatic conditions, respectively. This sample also retained 100% of its initial specific capacitance when discharged at a very high current density of 40 Ag-1. These values are substantially enhanced compared to previously reported data using a nearly analogous method (CBD with higher reagent conc.), with our method, cost-wise, offering economic advantages relative to results obtained with similar materials and other methods (e.g., hydrothermal).