Microwave-assisted hydrothermal synthesis of electrochemically active nano-sized Li2MnO3 dispersed on carbon nanotube network for lithium ion batteries

Electrochemically active Li2MnO3 nanoparticle dispersed on carbon nanotube (CNT) network has been successfully synthesized by microwave-assisted hydrothermal (MAH) process. To the best of our knowledge, this is the first report showing the formation of Li2MnO3 nanoparticle on CNT network using MnO2-coated CNT composite. Appearance of superlattice peak in X-ray diffraction (XRD) pattern and Raman-active modes near the lower wavelength region of Raman spectra reveals the structure transition from spinel LiMn2O4 to layered-type Li2MnO3 phase. The X-ray absorption near edge spectra (XANES) shows increase in average oxidation state of Mn ion from 3.5+ to 4+, and Mn-O and Mn-Mn peak intensity variations observed from extended X-ray absorption fine structure (EXAFS) are well evidenced for the formation of ordered Li2MnO3 structure. Electrochemical performance of Li2MnO3 nanocomposite electrode material prepared from higher LiOH concentration shows much higher capacity than spinel component alone. This synthetic strategy opens a new way for effective synthesis of electrochemically active Li2MnO3 on CNT network, making it suitable for advanced lithium ion battery. (C) 2014 Elsevier B. V. All rights reserved.