Ultrafine beta-FeOOH and Fe3O4 obtained by precipitation method: comparative study of electrical and electrochemical properties
| Autor: | L.V. Mokhnatska, V.O. Kotsyubynsky, V.M. Boichuk, M.L. Mokhnatskyi, Kh.V. Bandura, A.I. Kachmar, M.A. Hodlevska, V.V. Bachuk |
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| Jazyk: | English<br />Ukrainian |
| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Фізика і хімія твердого тіла, Vol 21, Iss 4, Pp 680-688 (2020) |
| Druh dokumentu: | article |
| ISSN: | 1729-4428 2309-8589 |
| DOI: | 10.15330/pcss.21.4.680-688 |
| Popis: | In this work, ultrafine powders of b-FeOOH and Fe3O4 have been obtained by the precipitation method. The values of the specific surface area for materials b-FeOOH and Fe3O4 are 101 and 135 m2/h. Frequency dependences of specific electrical conductivity have been obtained in the temperature range of 20-150 oC. It has been found that the materials show a superlinear dependence (SPL). In addition, the crossover energies from dc to JPL and from JPL to SPL have been calculated: Edc = 0.55eV, Ep1 = 0.51eB, Ep2 = 0.16eB and Edc = 0.22 eV, Ep1 = 0.21eB, Ep2 = 0.1 eB. Potentiodynamic studies have been performed at a scan rate from 1 mV/s to 50 mV/s. The b-FeOOH electrode material showed a specific capacitance value of 80 F/g at a scan rate of 1 mV/s, while the specific capacitance of the Fe3O4 material reached 32 F/g. Galvanostatic measurements have been done for discharge currents of 0.05 A/g, 0.1 A/g - 0.25 A/g. b-FeOOH sample is characterized by the maximum specific energy value of 8 W h/kg at the value of specific power equal to 20 W/kg, and Fe3O4 material is characterized by the maximum specific energy of about 3.5 W h/kg. |
| Databáze: | Directory of Open Access Journals |
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