Boosting the Power-Generation Performance of Micro-Sized Al-H2O2 Fuel Cells by Using Silver Nanowires as the Cathode

Abstract

Micro-sized fuel cells represent one of the pollution-free devices available to power portable electronics. However, the insufficient power output limits the possibility of micro-sized fuel cells competing with other power sources, including supercapacitors and lithium batteries. In this study, a novel aluminum-hydrogen peroxide fuel cell is fabricated using uniform silver nanowires with diameters of 0.25 µm as the catalyst at the cathode side. The Ag nanowire solution is prepared via a polyol method, and mixed uniformly with Nafion and ethanol to enhance the adhesion of Ag nanowires. We carry out electrochemical tests, including cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization, to characterize the performance of this catalyst in H 2 O 2 reduction. The Ag nanowires exhibit a high effectiveness and durability while catalyzing the reduction of H 2 O 2 with a low impedance. The micro-sized Al-H 2 O 2 fuel cell equipped with Ag nanowires delivers a power density of 43 W·m −2 under a low concentration of H 2 O 2 (0.1 M), which is substantially higher than the previously reported devices. Energies 2018, 11, 2316 2 of 10 However, the practical energy density of Al-H 2 O 2 FCs was still insufficient for powering practical micro-sized devices, due to their limited H 2 O 2 catalytic area, poor activity of H 2 O 2 catalyzation, self-decomposition reactions of hydrogen peroxide, as well as aluminum corrosion [9]. Among the above limitations, the cathode performance related to the H 2 O 2 catalyzation plays a vital role in determining the overall fuel cell performance [10-12]. Extensive studies have been carried out in exploring suitable cathode catalysts and architectures for catalyzing H 2 O 2 reduction reactions. Patrissi et al. employed a textile flocking technique to fabricate a microfiber carbon electrode coated by a layer of alloy of Pd and Ir as the cathode [13]. Yang et al. synthesized nano-island-shaped silver particles [2]. The cathode material was achieved by electrodepositing the metallic Ag catalyst on a Ni-foam substrate. Even though Al-H 2 O 2 fuel cells equipped with these cathodes exhibited high power densities, the techniques and materials demonstrated in these works were typically expensive and time-consuming.Here, silver nanowires (Ag NWs) were synthesized and utilized for the first time as the hydrogen peroxide reduction reaction catalyst. The morphology and structure of the Ag NWs coated on carbon paper (denoted as Ag NW//CC hereafter) were characterized using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). Electrochemical testing methods, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization curve, were carried out to investigate its catalytic activity and stability. Finally, we designed and fabricated a microfluidic Al-H 2 O 2 FC, and characterized its power-generation performance. Results and Discussions Characterization of Electrode SurfaceThe morphologies of Ag NW//CC were firstly ...

Study of a Thin Film Aluminum-Air Battery

“…Reaction (4) is easier to realize than Reaction (2) because it is a two-electron process and necessitates a less efficient electrocatalyst, even though it corresponds to a smaller V OC . Subsequent reduction of H 2 O 2 , for example, by the following reaction [11,12]…”

Biological Hair-Inspired AgNWs@Au-Embedded Nafion Electrodes with High Stability for Self-Powered Ionic Flexible Sensors

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