LiNi(0.5)Mn1.5O(4-delta) (LNMO) as Co-free cathode for lithium ion batteries via solution-gel synthesis: Particle size and morphology investigation

Abstract

LiNi0.5Mn1.5O4-delta (LNMO) is a potential candidate for high voltage Co-free cathodes in lithium-ion batteries. In this study, pre-calcination temperature, time, and oven type are showcased as important parameters influencing the particle size and morphology of the LNMO powder synthesized from the aqueous citric acidacetates-NH3 based method. These parameters determine the amount of organic residues in the precursor powder. A superior initial discharge capacity and capacity retention are obtained by an optimum combination of the particle size and morphology for the Li vertical bar LNMO coin cells. Pre-calcination in a forced convection oven at 200 degrees C for 40 h results in a voluminous and foam-like LNMO precursor powder morphology with the lowest amount of organic residue, leading to a similar to 1-4 mu m powder with well-defined facets. Applying 24 h pre-calcination at 170 degrees C in a natural convection oven results in large LNMO aggregates of similar to 70 mu m. Ballmilling of the crystalline LNMO powder is effective to reduce the agglomeration and particle size but deteriorates the electrochemical performance. An initial discharge capacity of 121 mA h g(-1) at 0.2 C and a capacity retention of 90% after 400 cycles at 2 C are obtained from the samples prepared by 40 h pre-calcination at 200 degrees C in a forced-convection oven. (C) 2021 Elsevier B.V. All rights reserved.