<p>Electrode is one of the components that play a crucial role in determining the electrochemical performance of energy storage devices (ESDs). Traditional electrode typically incorporates an insulating binder that adds dead weight to the electrode, resulting in poor conductivity. A viable solution would be to introduce the active material directly grown on conducting substrate surface to boost the performance of ESD. Herein, a microwave-assisted hydrothermal approach was utilized to prepare the binder-free nickel–cobalt phosphate electrode for ESD applications. The optimized synthesis parameters, e.g., temperature, reaction time, and Ni:Co precursor ratio, were statistically predicted by using optimal (custom) design in the Design of Experiment (DoE) software. The optimized binder-free nickel–cobalt phosphate electrode (Ni-Co-P electrode) with the highest performance was fabricated at 123.5&#xa0;°C for 10.5&#xa0;min with 1:1 ratio of Ni:Co. XRD and FESEM showed the successful growth of crystalline Ni–Co–P active material with flower- and flake-like morphologies on the nickel foam surface. The crystalline structure had a higher structural stability, making the Ni–Co–P active material challenging to damage during the electrochemical reactions. Besides, the combination of flower- and flake-like structures offered a large surface area for electrochemical reactions. The binder-free Ni-Co-P electrode exhibited higher specific capacity (2328.0&#xa0;C&#xa0;g⁻¹) and areal capacity (0.81&#xa0;C&#xa0;cm⁻²), excellent cycling stability (91.5%), and lower resistances. The incorporation of Ni and Co in the Ni–Co–P promotes more electroactive sites for electrochemical reactions, providing superior electrochemical performance. Hence, these results make Ni–Co–P electrode an excellent candidate as a battery-type electrode for ESD applications.</p> Graphical Abstract <p></p>