Understanding the nature of low-potential Li uptake into high volumetric capacity molybdenum oxides

A simple method to prepare (Na0.25MoO3) provides a material that displays very good properties as negative electrodes in lithium-ion batteries. Low- potential Li insertion below 300 mV is associated with dramatic transformation of the initial structure, leading to an amorphous material which exhibits excellent cyclability with a high reversible specific capacity of 940 mA/g in the voltage window of 3.0-0.005 V (volumetric capacity of 4000 mAh/cm(3)). For the first time, two complementary tools, Li-7 nuclear magnetic resonance and X-ray absorption spectroscopy, demonstrate that on Li insertion at low potential, a complex amorphous composite is formed consisting of a LiMo-suboxide in intimate contact with lithium oxide. (C) 1998 The Electrochemical Society. S1099-0062(98)02-049-5. All rights reserved.