Preparation and Electrochemical Performance of Nano-LiNi0.05Mn1.95O4 Cathode Materials by a Low-Temperature Molten-Salt Combustion Method

Nano-LiNi 0.05 Mn 1.95 O 4 cathode materials with nano-sized particles were successfully synthesized by a low temperature molten-salt combustion method at 400 °C for 1 h and then two-stage calcination at 600 °C for 3 h. The crystal structures and morphologies of nano-LiNi 0.05 Mn 1.95 O 4 were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). All obtained samples with good crystallinity were identified as the cubic spinel structure of LiMn 2 O 4 . The lattice parameters and the particle size of samples decreased as the Ni doped. The effects of Ni 2+ ion doping on the electrochemical properties of nano-LiNi 0.05 Mn 1.95 O 4 were investigated by a galvanostatic charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the nano-LiNi 0.05 Mn 1.95 O 4 sample exhibited the initial discharge capacity of 112.4 mAh g -1 with capacity retention of 80.7% after 1000 cycles at 1.0 C (1 C = 148.0 mAh g -1 ). In addition, the nano-LiNi 0.05 Mn 1.95 O 4 sample exhibited good rate capabilities at different current densities from 0.5 C to 5.0 C. These improvements are attributed to the synergistic effects of the nano-structure and nickel doping of the LiNi 0.05 Mn 1.95 O 4 sample.