Electrochemical Performance and Phase Transitions between 1.5 and 4.9 V of Highly-Ordered LiNi0.5Mn1.5O4 with Tailored Morphology: Influence of the Lithiation Method

We report about the electrochemical performance in the potential range 1.5 to 4.9 V of highly ordered, stoichiometric LiNi0.5Mn1.5O4 with spinel structure and tailored morphology. Structural and morphological parameters are optimized for obtaining maximum energy density in Li-ion cell applications. The effect of the discharge cutoff on the cathode capacity, cycling stability and coulombic efficiency is discussed. Li-rich structures with composition Li1+xNi0.5Mn1.5O4 (0 < x < 1) obtained via electrochemical lithiation are investigated via ex-situ XRD and SEM analysis. The results are compared with those obtained via a chemical lithiation method, showing that the phase transition from cubic LiNi0.5Mn1.5O4 to tetragonal Li2Ni0.5Mn1.5O4 occurs via a two-phase mechanism with no evidence of intermediate phases. The superior electrochemical performance of the synthesized cathode material is ascribed to its specific morphology that provides suitable properties for reduced side-reactions with the electrolyte and low impact of the volumetric changes during cycling. (C) The Author(s) 2016. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. All rights reserved.