Seminaria Naukowe


Wydział Nauk Ścisłych, Przyrodniczych i Technicznych zaprasza do udziału w otwartych Seminariach Naukowych, w trakcie których pracownicy wydziału oraz współpracujący z wydziałem naukowcy prezentują wyniki innowacyjnych i unikatowych badań naukowych


Prelegent: Wissem Zayani

Temat: New nanoparticles of (Sm, Zn)-codoped spinel ferrite as negative electrode in Ni/MH batteries: study of structural, morphological and electrochemical properties

Sterszczenie:

Ni-MH battery has become very important and widely used in our everyday life thanks to its easy storage, and transport as well as its capacity to function during several charge and discharge cycles. Traditional hydrogen storage alloys, comprising AB, AB2, AB3, AB5 (where A is a rare earth element and B is a transition element) and magnesium-based alloys were thoroughly tested as electrode materials for Ni/MH accumulators. To date, Ni-MH battery often only uses AB5 hydrogen storage alloys as anode materials. In these last few years, researchers have tried to develop new materials for hydrogen storage, such as nanotubes and perovskites.

Spinel ferrite nanomaterials with the general formula of MFe2O4 (M = Zn, Ni, Fe, Co, Cu and others) are a new candidates used as anode material in Ni-MH battery, it has a wide range of application in several sectors, such as photocatalysis, magnetic resonance imagery (MRI), gas sensors, nanotechnology and medicine. Spinel ferrites can be prepared using many processes, such as hydrothermal synthesis, sol-gel technique, ceramic method, co-precipitation, thermal decomposition and ball-milling technique. As part of our work, we are looking for new materials that are less expensive than metal alloys used as negative electrodes in Ni-MH batteries with similar performance. For this reason, a new simple technique of synthesis, such as the sol-gel method is considered for ionic compounds, which is much more economic compared to those applied for intermetallic compounds, like induction furnace melting and mechanosynthesis.

present report the usefulness of choosing this family of inorganic compounds is discussed. Both, elaboration methodology, structural and morphological characterizations will be approached. The experimental details of all the used electrochemical techniques will have also been introduced.

In this presentation the effort is focused on the effect of the partial substitution of zinc (II) by a trivalent Sm cation for the bond of a divalent cation on the spinel structure and its implications on electrochemical cycling, catalytic activity and composite electrode stability in strong alkaline solution. An attempt will be made to find a correlation between the evolution of the different functional parameters of ferrite spinel based electrode (exchange current density of H2O/H2 system, Nernst potential, atomic hydrogen diffusivity and electrochemical discharge capacity) as a function of the number of charge/discharge cycles in view of stability (cycle life) of the ionic electrode material.

In a second step, the degradation process of the ferrite-based electrode will be highlighted and capacity fade compared with LaNi5-type compound, which is the alloy most widely used as an anode material in the Ni-MH battery. This comparison is carried out to establish whether the spinel family is a good candidate as anode material in terms of its corrosion resistance and the catalytic activity towards H2O/H2 redox system.

Seminarium odbędzie się 17.03.2021 o godzinie 11:30

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