Studies on electrochemical magnesiumintercalation in molybdenum trioxide

Abstract

Electrochemical magnesium ion intercalation chemistry of MoO3 has been studied in this work. Submicron-sized MoO3 has been synthesized from commercial micron-sized MoO3 by a facile oxalic acid method, which was confirmed by SEM and XRD. A beaker-type three-electrode measurement cell was designed using activated carbon as the counter electrode, which enabled the test of magnesium intercalation into the host material at the working electrode without problem when conventional organic electrolytes are used. The electrochemical magnesium intercalation into MoO3 has been confirmed by cyclic voltammetry, galvanostatic discharge/charge, powder XRD and EDS measurements. Reversible reduction and oxidation peaks were obseved in cyclic voltagramms as well as discharge/charge cycles, corresponding to magnesium insertion and deinsertion, respectively. The reversibility was also confirmed by XRD measurement which also showed that a new phase is formed during the discharge and the discharge/charge processes are a pseudo two-phase reaction. With cycles, a degradation in crystallinity was observed. ⓒ 2014 DGIST