A new strategy to quickly synthetize true nanoparticles of the spinel LiMn2O4 by using a microwave-assisted hydrothermal route

Based on a microwave-assisted hydrothermal reaction, a new route is proposed to prepare highly pure true nanoparticles (≤15 nm) of the single-phase spinel LiMn 2 O 4 (LMO) at a low temperature (140 °C) and short reaction time (5 min), using exclusively water-soluble reagents. The obtention of this material was confirmed by using different techniques such as X-ray diffractometry, Rietveld crystal structure refinement, inductively coupled plasma-atomic emission spectroscopy and high-resolution transmission electron microscopy. Electrochemical evaluations were performed by using cyclic voltammetry and galvanostatic charge and discharge tests. Only electrodes prepared from spinel LMO nanoparticles with an average size of ~15 nm showed electrochemical activity. From charge and discharge tests at a constant rate of C/5, the electrodes prepared from this active material exhibited an initial specific capacity of 128 mA h g –1 with a capacity retention of 95% after the 27 th cycle. The hallmark of the synthesis route here described is the saving of energy while preparing truly nanoparticulate LMO with excellent chemical, structural and promising electrochemical properties. • Highly pure nanoparticles (≤15 nm) of LiMn 2 O 4 (LMO) are prepared by a new route. • The LMO preparation is based on a microwave-assisted hydrothermal reaction (MWH). • Low temperature, short time and water-soluble reagents are used in the MWH reaction. • LMO nanoparticles show excellent chemical, structural and electrochemical properties.