Improving electrochemical performances of LiNi0.5Mn1.5O4 by Fe2O3 coating with Prussian blue as precursor

Abstract

LiNi0.5Mn1.5O4 (LNMO) cathodes always suffer from severe capacity fading because of the oxidization of electrolyte and the dissolution of transition metal. Surface modification has been widely recognized as one of the most effective approaches. Herein, a uniform Fe2O3 layer was coated on LNMO via a simple solid-state method with Prussian blue as precursor. The SEM, TEM, XPS, and XRD results show that the Fe2O3 layer was effectively coated on the surface of LNMO. Fe2O3 layer not only increased the specific capacity of Li/LNMO@Fe2O3–0.65% (more than 120 mAh g−1, 2 C) but also improved the capacity retention (more than 90% after 300 cycles at 25 °C). While those of LNMO are about 94 mAh g−1 and 74%, respectively. These are owing to the successful suppression of side reactions and the dissolution of Mn and Ni. Therefore, this long-term cycling coated material is a promising candidate for high-energy lithium-ion batteries.