## 3 Results
The potential window is mainly determined according to the range where effective faradaic reactions occur. At a defined scan rate, the specific capacitance is correlated with the curvilinear integrated area positively based on CV evaluation [43]. Clearly, the maximum area of the CV curve is achieved at a Ni:Co ratio of 5:5. Figure 4b displays the CV curves of the Ni\({}_{0.5}\)Co\({}_{0.5}\)(OH)\({}_{2}\) electrode, tested at scan rates of 2, 5, 10, 20, and 50 mV/s. The coupled redox peaks in the CV curves shift positively or negatively with increased scan rates. The classical phenomenon also confirms the pseudocapacitive property of the obtained material [55]. Besides, the relationship of peak currents and the square root of the scan rates delivers a linear response with a steep slope, as described in the inset of Figure 4b. The distortion of the CV curves, obtained from 2 to 50 mV/s, is almost negligible. The characteristics above illustrate the excellent reversibility and rapid response of the Ni\({}_{0.5}\)Co\({}_{0.5}\)(OH)\({}_{2}\) electrode, promisingly leading to a desirable rate capability [56]. The GCD tests through the same three-electrode system were conducted on the binary hydroxide electrodes to demonstrate the electrochemical properties further. The GCD curves of the Ni\({}_{1-x}\)Co\({}_{x}\)(OH)\({}_{2}\) electrodes, measured at current densities of 1, 2, 5, 10, and 20 A/g in a potential range of 0-0.5 V (vs. Ag/AgCl), are shown in Figure 5a-e, respectively. As expected, all non-linear curves deliver well-defined plateaus, arising from redox reactions, also suggesting the pseudocapacitive features of the synthesized materials [54]. What is more, the plateaus are still dimly visible, even at a current density of 20 A/g, which implies a slight decay of the specific capacitance at high current density could possibly be reached. In GCD measurements, the specific capacitance is proportional to the discharge time [43]. Figure 5f intuitively depicts that the proposed Ni\({}_{0.5}\)Co\({}_{0.5}\)(OH)\({}_{2}\) electrode takes the longest time to complete one discharge process, which is in good agreement with the CV results exhibited in Figure 4a. Figure 4: (a) Cyclic voltammetry (CV) curves of the Ni\({}_{1-x}\)Co\({}_{x}\)(OH)\({}_{2}\) electrodes at scan rate of 2 mV/s. (b) CV curves of the Ni\({}_{0.5}\)Co\({}_{0.5}\)(OH)\({}_{2}\) electrode at scan rates from 2 to 50 mV/s. The specific capacitances based on the GCD tests were determined according to Equation (1). The calculated values as a function of current densities for all as-prepared electrodes are plotted in Figure 6a. All of the function graphs show a similar attenuation tendency, namely, the produced specific capacitances decrease accompanied by the boost of current densities. Admittedly, the unsatisfying fade is inevitable, owing to the limited diffusion of electrolyte ions (OH- in this work). Briefly, in comparison with low current density, the time for OH- transfer is inadequate at high current density, leading to the fact that involved active material in redox reactions is also insufficient [57]. The specific capacitance becomes greater with the content of Co in the binary hydroxide until the intermediate ratio. Beyond this ratio, a decrease in capacitive performance appears. This phenomenon is consistent with previous literature [58, 59, 60, 61, 62]. The Ni\({}_{0.5}\)Co\({}_{0.5}\)(OH)\({}_{2}\) electrode delivers high specific capacitances of 2807, 2751, 2622, 2444, and 2222 F/g at current densities of 1, 2, 5, 10 and 20 A/g, which is attributed to the integrated nanosheet/nanowire geometry and broadened redox behavior at a Ni:Co ratio of 5:5. The specific capacitance, reached as an important parameter for supercapacitors, manifests in the great application prospect of the obtained Ni\({}_{0.5}\)Co\({}_{0.5}\)(OH)\({}_{2}\) electrode.