xLi2MnO3-yLiMn2O4-(1-x-y)LiNi0.5Mn0.5O2 for Lithium Ion Batteries

Wednesday, 31 May 2017
Grand Ballroom (Hilton New Orleans Riverside)
M. LopezdeVictoria (University of Puerto Rico), S. M. Nieto Ramos (Universidad del Turabo), L. Torres Castro (Sandia Laboratory), V. Dorvilien (University of Puerto Rico), R. K. Katiyar (Dept. of Physics, University of Puerto Rico), B. Tripathi Sr. (Department of Physics, University of Puerto Rico San Juan), G. Morell (University of Puerto Rico, Rio Piedras Campus), and R. S. Katiyar V (Department of Physics University of Puerto Rico San Juan)
Lithium-ion batteries are considered as an important power source for electric and hybrid electric vehicles. Li2MnO3 based composite cathode materials are one of the most investigated cathode materials due to their ability to provide high discharge capacity and excellent rate capability. In this study, we have focused on synthesizing a lithium intercalated cobalt-free layered-layered-spinel composite cathode material xLi2MnO3-yLiMn2O4-(1-x-y) LiNi0.5Mn0.5O2 (LLNMO) by solvothermal synthesis technique. The structure of the compositions was characterized using X-ray Diffraction (XRD) and Raman Spectroscopy; peaks corresponding to layered and spinel structures were identified by both study methods. The surface morphology was studied by Scanning Electron Microscope (SEM). SEM images showed agglomerations of the nano-sized particles as well as the presence of the corresponding transition metals in the compositions which was confirmed with Electron Disperse Spectroscopy (EDS). The electrochemical performance was performed on coin cells, assembled in the Ar- filled glove box; we used Li as counter electrode, spread material as cathode and Celgard as separator. LiPF6 with EC:DMC in the 1:2 ratio was used as the electrolyte. Cyclic voltammogram (CV) was performed using a scan rate of 0.1 mV/s in a voltage range from 2.0-4.8 V. The charge discharge studies were performed using a current density of 10mA/g in the same voltage range. Finally, the Electrochemical Impedance Spectroscopy (EIS) was studied between cycles to understand the effect of cycling in the charge transfer resistance and also the internal resistance of the cells. The CV, charge discharge and EIS studies revealed that the lithium intercalated cathode material developed is a promising, structurally stable material for high energy and high power density applications.