High-performance Li1.2Mn0.6Ni0.2O2 cathode materials prepared through a facile one-pot co-precipitation process for lithium ion batteries

Abstract

In a quest to produce cathode materials for lithium ion batteries that yield high capacities, the Li1.2Mn0.6Ni0.2O2, lithium-manganese rich cathode materials were synthesized via a facile one-pot co-precipitation process with various ratios of urea at pH 9.0, 9.5, 10.0 and 10.5. The physical properties of the cathode materials were analysed by X-ray diffraction, Brunauer–Emmett–Teller surface area, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma mass spectrometry and energy dispersive spectroscopy. The X-ray diffraction study showed that the prepared materials were crystalline with an ordered layered structure in the respective unit cell parameters being indexed to a monoclinic C2/c space group. Scanning electron microscopy showed that Li1.2Mn0.6Ni0.2O2 particles are agglomerated, however pH 10.0 particles appear less agglomerated and possess a slightly higher surface area. The cathode materials were built into coin cells and displayed exceptional electrochemical performance in delivering more than 200 mAh g-1 at a constant current density of 20 mA g-1 in the voltage range of 2.0 V–4.8 V. In particular the cathode material made at pH 10.0 delivered an initial high discharge capacity of 266 mAh g-1 at 20 mA g-1 current density and maintained a discharge capacity of more than 220 mAh g-1 at 50 mA g-1 after 50 cycles.