Browsing by Author "Jijie, Roxana"

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    High performance silicon nanowires/ruthenium nanoparticles micro-supercapacitors
    (Elsevier, 2019) Bencheikh, Yasmina; Harnois, Maxime; Jijie, Roxana; Addad, Ahmed; Roussel, Pascal; Szunerits, Sabine; Hadjersi, Toufik; Abaidia, Seddik-El-Hak; Boukherroub, Rabah
    The continuous increase of small electronic devices calls for small energy storage components, commonly known as micro-supercapacitors, that can ensure autonomous operation of these devices. In this work, we propose a simple and straightforward method to achieve high energy and power densities of a silicon-based micro-supercapacitor, consisting of silicon nanowires decorated with ruthenium nanoparticles (Ru/Si NWs). The Si NWs are obtained through the common vapor-liquid-solid (VLS) growth mechanism, while a simple electroless process is used to deposit Ru nanoparticles. While silicon nanostructuration allows to increase the surface area, coating with Ru NPs introduces a pseudocapacitance necessary to attain high energy and power densities. The Ru/Si NWs micro-supercapacitor exhibits a specific capacitance of 36.25 mF cm−2 at a current density of 1 mA cm−2 in a neutral Na2SO4 electrolyte and a high stability over 25 000 cycles under galvanostatic charge-discharge at 1 mA cm−2. A solid state supercapacitor is then fabricated with symmetric electrodes separated by a polyvinyl alcohol/sulfuric acid electrolyte. The device displays a specific capacitance of ∼18 mF cm−2 at a current density of 1 mA cm−2 and a specific power density 0.5 mW cm−2. This solid-state nanowire device also exhibits a good stability over 10 000 galvanostatic charge-discharge cycles