Simple Co-precipitation Synthesis of Truncated-Octahedral LiNi0.5Mn1.5O4 Cathode Materials for Li-ion Batteries

Abstract

Spinel LiNi0.5Mn1.5O4 (LNMO) is a potential candidate of cathode material for high-energy lithium-ion batteries because of its high operating voltage, three-dimensional Li+ diffusion network, and cobalt-free composition. However, its electrochemical performance is strongly influenced by particle morphology. In this study, a truncated-octahedral LNMO cathode was synthesized via a simple co-precipitation method. The crystal structures and morphologies were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the electrochemical properties of LNMO were evaluated using galvanostatic charge–discharge measurements and electrochemical impedance spectroscopy (EIS). The LNMO sample exhibited a cubic spinel structure with the Fd-3m space group. SEM observations confirmed that the LNMO sample exhibits a truncated octahedral morphology, exposing both {111} and {100} facets. Electrochemical impedance spectroscopy revealed that the LNMO sample exhibited charge-transfer resistance (100.3 Ω), indicating favorable interfacial charge-transfer kinetics. In addition, the LNMO cathode maintained approximately 80% capacity after 49 cycles at a high current density.