Open AccessUltrafine beta-FeOOH and Fe3O4 obtained by precipitation method: comparative study of electrical and electrochemical properties
Author(s) -
L. V. Mokhnatska,
Volodymyr Kotsyubynsky,
Volodymyr Boichuk,
M. L. Mokhnatskyi,
Khrystyna Bandura,
Andrii Kachmar,
Myroslava Hodlevska,
V.V. Bachuk
Publication year - 2020
Publication title -
fìzika ì hìmìâ tverdogo tìla
Language(s) - English
Resource type - Journals
eISSN - 2309-8589
pISSN - 1729-4428
DOI - 10.15330/pcss.21.4.680-688
Subject(s) - materials science , horizontal scan rate , capacitance , electrochemistry , analytical chemistry (journal) , precipitation , specific surface area , electrical resistivity and conductivity , electrode , supercapacitor , specific energy , chemistry , thermodynamics , electrical engineering , chromatography , cyclic voltammetry , physics , meteorology , biochemistry , engineering , catalysis
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.