The LiZnxNi0.5-xMn1.5O4 spinel with improved high voltage stability for Li-ion batteries

• Zn is employed as dopant in LiNi0.5Mn1.5O4.
• The effects of Zn doping on structure and performance are investigated.
• LiZn0.08Ni0.42Mn1.5O4 shows excellent rate capability and cyclic performance.
• The mechanism of performance improvement by Zn doping is examined.

The effects of Zn substitution for Ni on the crystal structure and electrochemical properties of LiZnxNi0.5-xMn1.5O4 (x = 0 − 0.5) are investigated. The LiZnxNi0.5-xMn1.5O4 samples, which were synthesized by a sol-gel method, were analyzed by X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), battery cycling test, cyclic voltammetry (CV), and X-ray photoelectron spectroscopy (XPS). Of the compositions investigated, the LiZn0.08Ni0.42Mn1.5O4 delivered improved cycle-life and C-rate performance even at elevated temperature compared with those of Zn-free LiNi0.5Mn1.5O4. XRD and XPS results show that a thick positive electrode/electrolyte interphase film is formed on the surface of the x = 0.08 electrode, which may prevent the continuous electrolyte oxidation during cycling.