Dopant depends on morphological and electrochemical characteristics of LiMn 2– X Mo X O4 cathode nanoparticles

For the first time, solid solutions of LiMn2–X Mo X O4 nanoparticles were synthesized by combustion method at 700 °C in air. The synthesized LiMn2–X Mo X O4 (X = 0.0–0.2) nanoparticles were characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy (FT-IR), Field emission-scanning electron microscopy, and Particle size analysis. The unit-cell constant is increasing from 8.237 to 8.293 A with the increase of Mo, the presence of Mo at X ≤ 0.05 in LiMn2–X Mo X O4 nanoparticles retained the spinel structure (Fd-3m), whereas on increasing the Mo (X ≥ 0.05 %), the ordering of Li+ ions in both octahedral and tetrahedral cationic position leads to the lowering of symmetry (P4132). On increasing the Mo content, prominent peak splitting and broadening are observed at 600–500 and 830 cm−1 for Li–Mn–O and Mo–O respectively in the FT-IR spectra. The TG/DTA spectrum reveals that the convenient formation of Li mangano-molybdate is at 700 °C. The voltammograms of all the samples show two redox peaks centered around 4 V except for the sample with higher Mo doping (X = 0.2). The sample with X = 0.03 shows higher redox peak current values. A marginal increase of 146 Ω R ct value was found for the LiMn1.97Mo0.03O4 nanomaterial after 10th cycle which is rather high for the rest of the materials. A discharge capacity retention of 88 % at 50th cycle is observed for X = 0.03 sample, while the other samples exhibit drastically reduced capacity. The LiMn1.97Mo0.03O4 nanoparticle can able to deliver higher and constant discharge capacity, and it may be a good alternative for the existing cathode materials.