Influence of post-annealing in N2 on structure and electrochemical characteristics of LiNi0.5Mn1.5O4

LiNi0.5Mn1.5O4 prepared by a spray drying method was re-treated in N2 at 500, 600 and 700 °C, respectively. Their structural and electrochemical properties were studied by means of Fourier transform infrared(FTIR), X-ray diffraction(XRD), and charge-discharge tests. The space group of the LiNi0.5Mn1.5O4 transforms from P4332 to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Fd\bar 3m$$\end{document} at an annealing temperature of 700 °C. The electrochemical characteristics of the treated samples are closely related to the annealing temperature. The sample treated in N2 at 500 °C shows both an improved rate capability and cyclic performance at a high temperature compared with the as-prepared sample, while the sample treated in N2 at 700 °C shows dramatically decrease in its reversible capacity.