Electrochemical performance of pseudo-capacitor electrodes fabricated by Electrophoretic Deposition inducing Ni(OH)2 nanoplatelets agglomeration by Layer-by-Layer

Abstract

The electrochemical behaviour of ceramic semiconductors not only depends on the characteristics of the electroactive material but also on the processing method, the nanoparticles arrangement and the consolidation degree of the formed microstructure. In this sense, the use of nanoparticles with plane morphologies (disc, platelets, etc.) results interesting due to the formation of conduction pathways produced as a consequence of their laminar structures. Electrophoretic Deposition (EPD) is a shaping methodology which allows achieving high degrees in nanoplatelets packing by controlling their alignment during the coating process specifically over 3D substrates. In this work, we have studied the effect of a moderate nanoplatelets 2 agglomeration, by tuning their surfaces with a polyelectrolyte multilayer following a Layer-by-Layer (LbL) methodology and fixing the electric conditions of the EPD process. Overcoming the destructive effects of the full agglomeration of nanoplatelets, NiO films with a stable and extremely open macroporous structure were processed to coat Ni foams, improving the capacitive performance of pseudocapacitors leading to values of specific capacitances of 650 F/g. Results collected in this work also evidence that an efficient ordering and orientation of nanoplatelets in EPD mainly depends on tuning the suspension parameters (solid contents, conductivity, electrophoretic mobility, etc.) to avoid the massive flux and interactions among interparticles and electrohydrodynamic forces, as well as the interference of collateral electrode phenomena.

Electrophoretic deposition of RGO-NiO core-shell nanostructures driven by heterocoagulation method with high electrochemical performance

“…In addition, it is noteworthy to mention that the relaxation time constants corresponding to the 3D foam coated with thinner and more homogeneous layers (RGO/NiO0.7 and RGO/NiO1.5) maintain low values (< 9 ms) as NiO-bare electrode, exhibiting a more effective profiting of the electrochemical performance although the capacity behavior decay (reflected by lower values of CPE-P and Φ MAX ). Consequently we can conclude that the improvement of the RGO/NiO capacitance is mainly due to the faster electron transfer through the hybrid structure, contrarily that occurs in a pseudocapacitor, where the capacitance is strongly dependent on the exposed surface area as it has been reported for the NiO films modified by a layer-by-layer system of polyelectrolytes, and deposited by EPD in similar conditions [30].…”

“…The modification of the solid content of the suspension, the deposition time or the applied potential is enough to vary the thickness of the deposited electroactive layer. This technique allows the total and homogeneous coating of complex shapes on the whole exposed surface [30,31]. However, until now, the RGO/NiO films prepared by EPD are still a challenge.…”

A colloidal approach to prepare binder and crack-free TiO2 multilayer coatings from particulate suspensions: Application in DSSCs

“…This is a key step to break down weak agglomerates, stabilize and facilitate powders mixing, removing heterogeneities and defects that degrade relevant properties [21]. Moreover, it is critical to fit processing additives that modify the viscosity, flow, surface tension, wettability, etc., adapting the rheological behavior to the manufacturing technique [22] and controlling the particles assembly [23].…”

Framework of ruthenium-containing nickel hydrotalcite-type material: preparation, characterisation, and its catalytic application

“…Currently, there are many studies on the facile fabrication of bimetallic nickel systems that present potential alternatives for noble metal catalysts, which are expensive, in terms of the catalytic activity and stability. 23,[33][34][35][36][37][38][39][40][41][42] Thus, it will be interesting to introduce a small amount of trivalent ruthenium ions, which possess excellent activity in various organic transformations such as hydrogenation, C-C coupling, and metathesis, to the monometallic nickel HT-type materials. In this work, we intend to prepare HT-type a-Ni(OH) 2 containing ruthenium ions by using a simple coprecipitation method and used as a potential catalyst for the hydrogenation of nitro compounds to corresponding anilines.…”