New Synthesis Approach for High-Voltage Spinel LiNi0.5Mn1.5O4 a High Performance Positive Material for Lithium-Ion Batteries

Abstract

With the demand for increasing the energy and power, a lot of attention has been attracted by the LiNi0.5Mn1.5O4 (LNMO) spinel cathode material for lithium ion batteries, as it can be operated at a high voltage of ~ 4.7 V (versus Li+/Li) with offering 3-dimensional lithium-ion diffusion channels, allowing fast intercalation/deintercalation of lithium ions. However, it still remains challenging to get excellent rate capacity and cycling stability for LNMO material, especially at elevated temperature, due to the complex influencing factors and the undesired side reactions with the electrolytes. [1-5] Various synthesis techniques, material modifications, and morphology control for high-voltage spinel LNMO have been reported to improve the electrochemical performance.[4-7] Such as cation doping, surface coating, and creating nanostructures. Meanwhile, the particle morphology of the material, especially the surface crystallographic planes, can also have an obvious influence on the electrochemical properties of material itself.Herein, a new synthesis approach, allowing shorter material processing, will be presented, which leads to an achievement of special morphology of LNMO cathode material. The obtained LNMO material was characterized by means of X-rays diffractions (XRD), Raman spectrum, electron microscopy (SEM), and electrochemical measurements (CV, EIS, and galvanostatic charge-discharge test). The special morphology enables high-rate performance and cycle life simultaneously. The electrochemical performance was improved remarkably. Detailed discussion will be presented.