Electrochimica Acta, Vol.81, 191-196, 2012
Facile synthesis of micrometer Li1.05Mn1.95O4 and its low temperature performance for high power lithium ion batteries
Micrometer Li1.05Mn1.95O4 has been synthesized by solid state reactions with the nano-Mn3O4 as a precursor. X-ray diffraction, scanning electron microscopy and laser particle sizer are employed to investigate the structures. morphologies and particle size distributions of the powder. The micrometer Li 1.05Mn1.95O4 exhibits good rate performance at room temperature with a specific capacity of 98.4 mAhg(-1) at 5 C. The Li1.05Mn1.95O4/Li half cell also shows good cycling performance at elevated temperature with 90.5% of its initial capacity retained after 100 cycles at 1C. At -20 degrees C, the Li1.05Mn1.95O4 delivers a stable cycling performance with a specific capacity of 84.5 mAh g. 84.1% of the capacity at room temperature. The cyclic voltammetry (CV) and rate performance measurements illustrate an increasing polarization with decreasing the temperature. In addition, the diffusion coefficients of lithium ions (DLi+) in Li1.05Mn1.95O4 at various temperatures (25, 0, -10 and -20 degrees C) are determined to be in the magnitude of 10(-10) to 10(-12) cm(2) s(-1) by cyclic voltammetry (CV) method. (c) 2012 Elsevier Ltd. All rights reserved.