Search for content and authors

Synthesis of Micro- and Nano-Sized LiNi0.5Mn1.5O4 and LiNi0.5Mn0.5O2 Materials and Studies of Their Electrode Behavior in Li-Ion Cells

Yosi Talyosef 1Daniela Kovachevab Ronit Lavi Emilia V. Pecheva 2Nila Gorovab Radoseima Stoyanova Judi Grinblat Boris Markovsky 

1. Bar-Ilan University, Ramat-Gan 52900, Israel
2. Institute of Solid State Physics, Bulgarian Academy of Sciences (ISSP-BAS), 72, Tzarigradsko Chaussee blvd., Sofia 1784, Bulgaria


In the present work, we compare the electrochemical behavior of LiNi0.5Mn1.5O4 and LiNi0.5Mn0.5O2 electrodes prepared from micro- or nano-particles of the active material, in Li-ion cells. The electrochemical performance in terms of capacity, rate capability, electrode impedance, stability at elevated temperature, and ageing of the nano-materials in solutions, was compared to that of micro-particles. Nano-particles of the layered LiNi0.5Mn0.5O2 and spinel LiNi0.5Mn1.5O4 materials were synthesized by a modified self-combustion reaction, and micron sized particles were prepared via a solid-state reaction method.

It was established that stable electrochemical behavior could be obtained during prolonged cycling of these electrodes even at elevated temperatures (600C) in LiPF6/alkyl-carbonates solutions. We have found that nano-LiNi0.5Mn0.5O 2 and nano-LiNi 0.5Mn1.5O4 electrodes demonstrate a faster kinetics, more reversible electrochemical behavior, and superior capacity retention at high rates compared to their micro-sized counterparts.

We proposed that a stable electrochemical behavior of nano-LiNi0.5Mn0.5O2 electrodes under conditions of high temperature cycling/ageing and high oxidation potentials (> 4.5 V), may be related, in part, to stabilization of the electrode/solution interphase by developing surface films. The latter contain polycarbonates, LiF, Ni and Mn oxides and fluorides. An important finding is nearly constant impedance of nano- and micro-LiNi0.5Mn0.5O2 electrodes during ageing and cycling after these electrodes being stabilized at elevated temperatures. It was demonstrated that ageing of nano-particles proceeded with a partial Ni and Mn dissolution from LiNi0.5Mn1.5O4, as a result of which the complex domain structure of nano-particles is changed in terms of a more homogeneous Ni2+-to-Mn4+ distribution. For micro-particles, the partial dissolution of Ni and Mn was found to be limited.


Legal notice
  • Legal notice:

Related papers

Presentation: Poster at E-MRS Fall Meeting 2007, Symposium D, by Yosi Talyosef
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-21 16:18
Revised:   2009-06-07 00:44