High performance 5 V LiNi0.5Mn1.5O4 spinel cathode materials synthesized by an improved solid-state method

The high-performance LiNi0.5Mn1.5O4 has been prepared by an improved solid-state method, which is calcined in nitrogen at the first stage and in air at the second stage. The reaction process between nickel atoms and manganese atoms was changed by the improved solid-state method. The final product is a high purity cubic spinel structure (Fd3m) with high crystallinity, little impurities and excellent electrochemical performances. The EDX demonstrates that there is slightly lower nickel content and carbon content on the crystal surfaces. It shows a discharge capacity of 138 mAh/g at the first cycle and 133.9 mAh/g after 100 cycles at 0.1C rate. It also can deliver a discharge capacity of 111.3 mAh/g at 5C rate. The discharge capacity of the cathode at 55 degrees C is up to 124 mAh/g with capacity retention of 96.1% after 100 cycles. These results show that the improved solid-state method has potential application for the large-scale synthesis of LiNi0.5Mn1.5O4 in high power Li-ion batteries. (C) 2015 Elsevier B.V. All rights reserved.