Authors: B Das M V Reddy G V Subba Rao B V R Chowdari
Publish Date: 2007/11/13
Volume: 12, Issue: 7-8, Pages: 953-959
Abstract
The mixed oxide containing the triangular molybdenum clusters LiHoMo3O8 is prepared from the component oxides by onestep carbothermal reduction reaction at 750 °C It was characterized by powder Xray diffraction XRD scanning electron microscopy SEM and highresolution transmission electron microscopy HRTEM techniques Electrochemical studies were carried out at 24 °C and at 50 °C by galvanostatic cycling range 0005–30 V vs Li at 30 mA/g and cyclic voltammetry CV The firstcycle charge capacities at 24 °C and 50 °C after deep discharge to 0005 V are 180 and 315 ±5 mAh/g respectively corresponding to ∼35 and ∼60 moles of Li per mole of LiHoMo3O8 Cycling up to 70 cycles at 24 °C shows a gradual increase in the reversible capacity and finally reaches 290 ±5 mAh/g ∼56 moles of Li When cycled at 50 °C the reversible capacity reaches 470 ±5 mAh/g ∼91 moles of Li at the 40th cycle The coulombic efficiency ranged from 96 to 98 30–70 cycles 24 °C The differential capacity–voltage curves and the CV data show that the average potentials for the discharge and charge process occur at 10 V and 22 V respectively The observed exsitu XRD and HRTEM data on the electrodes in the discharged/charged states have been interpreted and a plausible reaction mechanism is proposed
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