| dc.description.abstract | Abstract
As fossil fuel reserves dwindle, the quest for sustainable energy solutions has become a global priority. Among the most promising approaches are energy storage technologies and electrochemical-based energy conversion devices. These methods are efficient, environmentally friendly, free from radiation hazards, and capable of delivering high performance. Key innovations include converting electrochemical energy into usable forms through electrochemical cells like fuel cells and storing it in batteries or electrochemical supercapacitors. Central to the efficiency of these technologies is the architecture of the electrodes within electrochemical cells, which conduct electrons from one half-cell to another which is produced by chemical reactions in the system. Over the past decade, researchers have made significant strides in developing highly porous architectures for electrocatalyst and electrochemical electrodes. These designs boast large surface areas, enhanced stability, and improved charge transport pathways, significantly boosting the performance of electrochemical cells.
In energy storage, our previous study focused on enhancing the performance of 3D all-solid-state micro-supercapacitors by utilizing nickel oxide (NiO) as a current collector within commercial nickel foam. This study introduces an innovative and straightforward method for producing electrodes with a large specific surface area, optimizing the application of active materials. The process exploits the commercial nickel foam, which is laser-cut into an interdigitated structure and then filled with Ni-based powder using dip coating techniques. Various chemical reactions were employed to coat the nickel foam with the nano-active material MnO2. This resulted in a novel current collector, NF-V2, with a 200-600 nm porosity range. Compared to commercial nickel foam (NF), this new structure offers a 30-fold increase in specific surface area and a substantial rise in active material loading (> 20 mg/cm2, up from less than 1 mg/cm2). Experiments on these highly porous 3D architectural electrodes demonstrate remarkable results, including an energy density of 671 µW h/cm2, which is 25 times higher than electrodes without filler, an area capacity of 19.34 F/cm2, and capacitance retention exceeding 95% at 5 mA/cm2. Furthermore, in the field of solid-state applications for micro-supercapacitors (MSCs), the highly porous electrode achieves a commendable areal capacity of 7.22 F/cm2 and an energy density of 263.9 µW h/cm2, making it appropriate for MSCs applications.
In energy conversion, our recent endeavor has yielded a breakthrough: creating a highly porous Ni electrode adorned with Fe3O4 for the Oxygen Evolution Reaction (OER). This undertaking is driven by the ambition to bolster the efficiency of water electrolysis through meticulous adjustments to the electrode′s porosity and the integration of active catalyst materials. Two distinct types of electrodes were meticulously crafted for the electrolysis process: self-manufactured nickel foam (NF-V3) and commercial nickel foam (NF), serving as a benchmark for comparison. Employing a dip coating process, the Ni porous structures were embellished with iron (II, III) oxide (Fe3O4), followed by a meticulous calcination process utilizing laser technology, culminating in the creation of Fe3O4/NF-V3 electrodes. Electrochemical tests unveiled the pivotal role of Fe3O4 in enhancing reaction kinetics. In a 1 M KOH solution at a current density of 10 mA, the Fe3O4/NF-V3 electrode exhibited an overpotential of 217.3 mV, significantly lower than its counterpart lacking Fe3O4, which registered an overpotential of 361.4 mV under identical conditions. Moreover, despite minor disparities in mass loading—less than 5 mg—the variances in porosity exhibited negligible effects on the electrode′s functionality. Notably, chronoamperometry tests conducted for 5 hours at a 155 mV overpotential underscored the stability and enduring performance of Fe3O4/NF-V3 electrodes. | en_US |