Dendrite like nanorod bundles of cobalt phosphate electrodes for efficient water splitting and energy storage applications

The design of multifunctional cost-effective electrode materials for energy storage and conversion are the most attractive and promising technologies for producing sustainable and clean energy. Herein, the cobalt phosphate electrodes are synthesized using a Successive Ionic Layer Adsorption and Reaction (SILAR) method on a nickel foam substrate with different cycle numbers such as 20, 40, 60, and 80. For comparison, we also fabricated pure cobalt hydroxide electrodes using similar experimental conditions. The electrochemical supercapacitor and oxygen evolution reaction electrocatalysis properties of these electrodes are systematically studied. The highest specific capacity of the optimized cobalt hydroxide and cobalt phosphate electrodes are found to be 455 and 895 F/g at a current density of 5 mA/cm 2 . Moreover, these electrodes also showed enhanced electrocatalytic activity for cobalt hydroxide and cobalt phosphate with overpotentials of 448 mV and 361 mV at a current density 20 mA/cm 2 respectively. The lower Tafel slope of 116 and 81 mV/dec 1 of cobalt hydroxide and cobalt phosphate indicated the faster reaction kinetics for oxygen evolution reaction. The experimental technique studied in this work provides insights onto the fabrication of the thin film electrodes via simple, easy, and cost-effective ways for energy generation and storage applications. • Interconnected sheets of cobalt phosphate hydrates are used for energy storage and generation. • The effect of different SILAR cycles is investigated for supercapacitor and OER study. • The bifunctional material showed excellent specific capacity of 895 Fg −1 . • The lowest overpotential of 361 mV is obtained at a current density 20 mA/cm 2 . • The samples have high durability and lowest Tafel slope of 81 mV dec −1 .