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Home  >  Journal list  >  MATERIALS TRANSACTIONS  >  Vol.49  No.4 (2008)  >  pp.824-828

MATERIALS TRANSACTIONS
<<Previous article Vol.49  No.4 (2008)   pp.824 - 828 Next article>>

Synthesis of Spinel-Type Magnesium Cobalt Oxide and Its Electrical Conductivity

Natsumi Kamioka1), Tetsu Ichitsubo1), Tetsuya Uda1), Susumu Imashuku1), Yu-ki Taninouchi1) and Eiichiro Matsubara1)
1) Department of Materials Science and Engineering, Kyoto University

This work devotes to investigate synthesis and electrical properties of spinel MgCo2O4 that is considered as a candidate of the cathode materials of magnesium-ion batteries in future. Samples were synthesized by two types of techniques: solid-state reaction and wet process. The crystal structures of the samples were analyzed by X-ray diffraction, and their electrical conductivities were obtained through the dc resistance and ac impedance measurements. By solid-state reaction, sample of a single MgCo2O4 phase was not obtained; a sample synthesized at 800°C for 24 h after milling of Co3O4 and MgO powder was comprised of dual phases of spinel-type and rocksalt-type structures, and samples synthesized at temperatures higher than 880°C showed a single rocksalt-type phase without electrical conductance. The former sample showed p-type semiconducting behavior as well as spinel-type Co3O4, but its electrical conductivity around room temperature was shown to exceed that of Co3O4. In contrast, a sample consisting of a single spinel-type phase was successfully synthesized by wet process, which exhibited an electrical conductivity of the order 10−2 Scm−1, being much higher than those of the samples synthesized by solid-state reaction. Thus, substitution of Co2+ in Co3O4 with Mg2+ is found to enhance the electrical conductivity of the spinel-type phase.


Keyword:
magnesium-ion batteries, rechargeable batteries, cathode, spinel, magnesium cobalt oxide, crystal structure, X-ray diffraction, electrical conductivity, solid-state reaction, wet process

Received: November 19, 2007
Accepted: January 30, 2008 , Published online: March 25, 2008
Copyright (c) 2008 The Japan Institute of Metals

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