## 3 Results and Discussion
### Characterization of the Prepared Nanopowder
The appearance of the resulting sample allows one to observe the formed ordered array of miniature planar nanostructures (\"pixels\") with a distance of 300 \(\upmu\)m between their centers (Figure 5b,c), which additionally testifies to the high addressability of material deposition and reproducibility of the electrode structure formation process using printing technologies. Figure 4: Microstructure of the obtained nanopowder (according to SEM data). Figure 5: The microplotter printing of functional film (**a**) and the appearance of the resulting miniature planar nanostructure array on a Ni substrate (**b,c**). When studying the microstructural features of the printed film by SEM, maps of element (Ni, Co, and O) distribution over the studied sample surface were built (Figure 6). The results clearly demonstrate the reduced content of nickel in the formed miniature planar nanostructures compared to the substrate surface. In the electrode \"pixels\" area, the presence of cobalt and increased oxygen concentration compared to the surface of the metal substrate are also observed. A more detailed analysis of the printed film microstructure showed that the diameter of individual miniature planar structures is about 140 \(\upmu\)m (Figure 7a). As can be seen from the micrograph of an individual \"pixel\", the gradient of particle distribution over the surface (coffee stain effect) is almost absent (Figure 7b). The main area of printed planar structures is a thin film of individual nanorods with periodic inclusions of larger spherical hierarchically organized formations (Figure 7c). Therefore, the microstructural features of the (M(CO3)0.5(OH)-0.11H2O)/(NiCo-LDH) (where M is Ni\({}^{2+}\) and Co\({}^{2+}\)) composite powder are preserved during functional ink preparation and electrode film application. Thus, the spherical formations, as in the case of the powder, consist of nanorods orthogonally arranged to their outer surface (Figure 7d-f), and the individual nanorods covering the main surface of the electrode \"pixels\" are 10-50 nm thick (Figure 7g-i). The results of AFM analysis of the film surface (Figure 8a,b) show that the main surface of the formed miniature planar nanostructures consists of anisotropic one-dimensional particles with a thickness of about 35 nm and a submicron length (400-1200 nm). At the  
Figure 6: Printed film microstructure and element distribution maps (Ni, Co, and O) on its surface. \[\mathrm{H_{2}O}+\mathrm{CO_{2}}\rightarrow\mathrm{2H^{+}}+\mathrm{CO_{3}}^{2-} \tag{4}\]0 Microstructure of the printed film (according to SEM data). same time, there is a tendency for the combination of the particles by side faces, forming agglomerates in the shape of \"stacks\". This film microstructure agrees well with the SEM results. In order to visualize the obtained film topography, the corresponding 3D images are given in Figure 8e,f. The mean square roughness of the material surface is 28 nm (for a pure substrate, this parameter is 8 nm). This value is close to the thickness of one-dimensional particles, which indicates the formation of an active electrode layer with a thickness comparable to that of a single particle. During the study of the film surface, its local electrophysical properties were also studied (Figure 8c,d). Thus, the surface potential distribution map (Figure 8c) shows areas with markedly higher values of this parameter (\(\sim\)0.1 eV). This may indicate that the film has insufficient conductivity (probably related to the lack of dense contact between the particles) for a uniform distribution of charges over its surface, resulting in the formation of areas with strongly prominent surface charges. On the map of capacitance gradient distribution over the material surface of the \"probe tip--sample microregion\" capacitor (Figure 8d), the boundaries between particles are practically not distinguished, which can also indicate a slightly reduced electronic conductivity or that its intergrain character is not strongly pronounced.